SubGraphs, Views, Shadows, and more

Cargo.toml

@@ -29,6 +29,7 @@ default = [
   "bevy_wgpu2",
   "bevy_sprite2",
   "bevy_render2",
+  "bevy_pbr2",
   "bevy_winit",
   "render",
   "png",
@@ -54,6 +55,7 @@ bevy_winit = ["bevy_internal/bevy_winit"]
 bevy_wgpu2 = ["bevy_internal/bevy_wgpu2"]
 bevy_render2 = ["bevy_internal/bevy_render2"]
 bevy_sprite2 = ["bevy_internal/bevy_sprite2"]
+bevy_pbr2 = ["bevy_internal/bevy_pbr2"]
 
 trace_chrome = ["bevy_internal/trace_chrome"]
 trace = ["bevy_internal/trace"]
@@ -142,6 +144,10 @@ path = "examples/2d/texture_atlas.rs"
 name = "3d_scene"
 path = "examples/3d/3d_scene.rs"
 
+[[example]]
+name = "3d_scene_pipelined"
+path = "examples/3d/3d_scene_pipelined.rs"
+
 [[example]]
 name = "load_gltf"
 path = "examples/3d/load_gltf.rs"

crates/bevy_ecs/src/archetype.rs

@@ -25,6 +25,11 @@ impl ArchetypeId {
         ArchetypeId(0)
     }
 
+    #[inline]
+    pub const fn invalid() -> ArchetypeId {
+        ArchetypeId(usize::MAX)
+    }
+
     #[inline]
     pub const fn resource() -> ArchetypeId {
         ArchetypeId(1)

crates/bevy_ecs/src/entity/mod.rs

@@ -26,6 +26,12 @@ pub struct Entity {
     pub(crate) id: u32,
 }
 
+pub enum AllocAtWithoutReplacement {
+    Exists(EntityLocation),
+    DidNotExist,
+    ExistsWithWrongGeneration,
+}
+
 impl Entity {
     /// Creates a new entity reference with a generation of 0.
     pub fn new(id: u32) -> Entity {
@@ -242,11 +248,8 @@ impl Entities {
     }
 
     /// Allocate an entity ID directly.
-    ///
-    /// Location should be written immediately.
     pub fn alloc(&mut self) -> Entity {
         self.verify_flushed();
-
         self.len += 1;
         if let Some(id) = self.pending.pop() {
             let new_free_cursor = self.pending.len() as i64;
@@ -294,6 +297,40 @@ impl Entities {
         loc
     }
 
+    /// Allocate a specific entity ID, overwriting its generation.
+    ///
+    /// Returns the location of the entity currently using the given ID, if any.
+    pub fn alloc_at_without_replacement(&mut self, entity: Entity) -> AllocAtWithoutReplacement {
+        self.verify_flushed();
+
+        let result = if entity.id as usize >= self.meta.len() {
+            self.pending.extend((self.meta.len() as u32)..entity.id);
+            let new_free_cursor = self.pending.len() as i64;
+            *self.free_cursor.get_mut() = new_free_cursor;
+            self.meta.resize(entity.id as usize + 1, EntityMeta::EMPTY);
+            self.len += 1;
+            AllocAtWithoutReplacement::DidNotExist
+        } else if let Some(index) = self.pending.iter().position(|item| *item == entity.id) {
+            self.pending.swap_remove(index);
+            let new_free_cursor = self.pending.len() as i64;
+            *self.free_cursor.get_mut() = new_free_cursor;
+            self.len += 1;
+            AllocAtWithoutReplacement::DidNotExist
+        } else {
+            let current_meta = &mut self.meta[entity.id as usize];
+            if current_meta.location.archetype_id == ArchetypeId::invalid() {
+                AllocAtWithoutReplacement::DidNotExist
+            } else if current_meta.generation == entity.generation {
+                AllocAtWithoutReplacement::Exists(current_meta.location)
+            } else {
+                return AllocAtWithoutReplacement::ExistsWithWrongGeneration;
+            }
+        };
+
+        self.meta[entity.id as usize].generation = entity.generation;
+        result
+    }
+
     /// Destroy an entity, allowing it to be reused.
     ///
     /// Must not be called while reserved entities are awaiting `flush()`.
@@ -342,23 +379,13 @@ impl Entities {
         self.len = 0;
     }
 
-    /// Access the location storage of an entity.
-    ///
-    /// Must not be called on pending entities.
-    pub fn get_mut(&mut self, entity: Entity) -> Option<&mut EntityLocation> {
-        let meta = &mut self.meta[entity.id as usize];
-        if meta.generation == entity.generation {
-            Some(&mut meta.location)
-        } else {
-            None
-        }
-    }
-
-    /// Returns `Ok(Location { archetype: 0, index: undefined })` for pending entities.
+    /// Returns `Ok(Location { archetype: Archetype::invalid(), index: undefined })` for pending entities.
     pub fn get(&self, entity: Entity) -> Option<EntityLocation> {
         if (entity.id as usize) < self.meta.len() {
             let meta = &self.meta[entity.id as usize];
-            if meta.generation != entity.generation {
+            if meta.generation != entity.generation
+                || meta.location.archetype_id == ArchetypeId::invalid()
+            {
                 return None;
             }
             Some(meta.location)
@@ -401,7 +428,7 @@ impl Entities {
 
     /// Allocates space for entities previously reserved with `reserve_entity` or
     /// `reserve_entities`, then initializes each one using the supplied function.
-    pub fn flush(&mut self, mut init: impl FnMut(Entity, &mut EntityLocation)) {
+    pub unsafe fn flush(&mut self, mut init: impl FnMut(Entity, &mut EntityLocation)) {
         let free_cursor = self.free_cursor.get_mut();
         let current_free_cursor = *free_cursor;
 
@@ -439,6 +466,16 @@ impl Entities {
         }
     }
 
+    // Flushes all reserved entities to an "invalid" state. Attempting to retrieve them will return None
+    // unless they are later populated with a valid archetype.
+    pub fn flush_as_invalid(&mut self) {
+        unsafe {
+            self.flush(|_entity, location| {
+                location.archetype_id = ArchetypeId::invalid();
+            })
+        }
+    }
+
     #[inline]
     pub fn len(&self) -> u32 {
         self.len
@@ -460,7 +497,7 @@ impl EntityMeta {
     const EMPTY: EntityMeta = EntityMeta {
         generation: 0,
         location: EntityLocation {
-            archetype_id: ArchetypeId::empty(),
+            archetype_id: ArchetypeId::invalid(),
             index: usize::max_value(), // dummy value, to be filled in
         },
     };
@@ -493,7 +530,24 @@ mod tests {
     fn reserve_entity_len() {
         let mut e = Entities::default();
         e.reserve_entity();
-        e.flush(|_, _| {});
+        unsafe { e.flush(|_, _| {}) };
         assert_eq!(e.len(), 1);
     }
+
+    #[test]
+    fn get_reserved_and_invalid() {
+        let mut entities = Entities::default();
+        let e = entities.reserve_entity();
+        assert!(entities.contains(e));
+        assert!(entities.get(e).is_none());
+
+        unsafe {
+            entities.flush(|_entity, _location| {
+                // do nothing ... leaving entity location invalid
+            })
+        };
+
+        assert!(entities.contains(e));
+        assert!(entities.get(e).is_none());
+    }
 }

crates/bevy_ecs/src/lib.rs

@@ -1227,6 +1227,7 @@ mod tests {
         assert_eq!(dropped2.load(Ordering::Relaxed), 1);
     }
 
+    #[test]
     fn clear_entities() {
         let mut world = World::default();
         world
@@ -1266,4 +1267,130 @@ mod tests {
             "world should still contain resources"
         );
     }
+
+    #[test]
+    fn reserve_entities_across_worlds() {
+        let mut world_a = World::default();
+        let mut world_b = World::default();
+
+        let e1 = world_a.spawn().insert(1u32).id();
+        let e2 = world_a.spawn().insert(2u32).id();
+        let e3 = world_a.entities().reserve_entity();
+        world_a.flush();
+
+        let world_a_max_entities = world_a.entities().meta.len();
+        world_b
+            .entities
+            .reserve_entities(world_a_max_entities as u32);
+        world_b.entities.flush_as_invalid();
+
+        let e4 = world_b.spawn().insert(4u32).id();
+        assert_eq!(
+            e4,
+            Entity {
+                generation: 0,
+                id: 3,
+            },
+            "new entity is created immediately after world_a's max entity"
+        );
+        assert!(world_b.get::<u32>(e1).is_none());
+        assert!(world_b.get_entity(e1).is_none());
+
+        assert!(world_b.get::<u32>(e2).is_none());
+        assert!(world_b.get_entity(e2).is_none());
+
+        assert!(world_b.get::<u32>(e3).is_none());
+        assert!(world_b.get_entity(e3).is_none());
+
+        world_b.get_or_spawn(e1).unwrap().insert(1.0f32);
+        assert_eq!(
+            world_b.get::<f32>(e1),
+            Some(&1.0f32),
+            "spawning into 'world_a' entities works"
+        );
+
+        world_b.get_or_spawn(e4).unwrap().insert(4.0f32);
+        assert_eq!(
+            world_b.get::<f32>(e4),
+            Some(&4.0f32),
+            "spawning into existing `world_b` entities works"
+        );
+        assert_eq!(
+            world_b.get::<u32>(e4),
+            Some(&4u32),
+            "spawning into existing `world_b` entities works"
+        );
+
+        let e4_mismatched_generation = Entity {
+            generation: 1,
+            id: 3,
+        };
+        assert!(
+            world_b.get_or_spawn(e4_mismatched_generation).is_none(),
+            "attempting to spawn on top of an entity with a mismatched entity generation fails"
+        );
+        assert_eq!(
+            world_b.get::<f32>(e4),
+            Some(&4.0f32),
+            "failed mismatched spawn doesn't change existing entity"
+        );
+        assert_eq!(
+            world_b.get::<u32>(e4),
+            Some(&4u32),
+            "failed mismatched spawn doesn't change existing entity"
+        );
+
+        let high_non_existent_entity = Entity {
+            generation: 0,
+            id: 6,
+        };
+        world_b
+            .get_or_spawn(high_non_existent_entity)
+            .unwrap()
+            .insert(10.0f32);
+        assert_eq!(
+            world_b.get::<f32>(high_non_existent_entity),
+            Some(&10.0f32),
+            "inserting into newly allocated high / non-continous entity id works"
+        );
+
+        let high_non_existent_but_reserved_entity = Entity {
+            generation: 0,
+            id: 5,
+        };
+        assert!(
+            world_b.get_entity(high_non_existent_but_reserved_entity).is_none(),
+            "entities between high-newly allocated entity and continuous block of existing entities don't exist"
+        );
+
+        let reserved_entities = vec![
+            world_b.entities().reserve_entity(),
+            world_b.entities().reserve_entity(),
+            world_b.entities().reserve_entity(),
+            world_b.entities().reserve_entity(),
+        ];
+
+        assert_eq!(
+            reserved_entities,
+            vec![
+                Entity {
+                    generation: 0,
+                    id: 5
+                },
+                Entity {
+                    generation: 0,
+                    id: 4
+                },
+                Entity {
+                    generation: 0,
+                    id: 7,
+                },
+                Entity {
+                    generation: 0,
+                    id: 8,
+                },
+            ],
+            "space between original entities and high entities is used for new entity ids"
+        );
+    }
 }

crates/bevy_ecs/src/query/state.rs

@@ -64,7 +64,7 @@ where
             matched_archetypes: Default::default(),
             archetype_component_access: Default::default(),
         };
-        state.validate_world_and_update_archetypes(world);
+        state.update_archetypes(world);
         state
     }
 
@@ -78,11 +78,8 @@ where
         }
     }
 
-    pub fn validate_world_and_update_archetypes(&mut self, world: &World) {
-        if world.id() != self.world_id {
-            panic!("Attempted to use {} with a mismatched World. QueryStates can only be used with the World they were created from.",
-                std::any::type_name::<Self>());
-        }
+    pub fn update_archetypes(&mut self, world: &World) {
+        self.validate_world(world);
         let archetypes = world.archetypes();
         let new_generation = archetypes.generation();
         let old_generation = std::mem::replace(&mut self.archetype_generation, new_generation);
@@ -93,6 +90,14 @@ where
         }
     }
 
+    #[inline]
+    pub fn validate_world(&self, world: &World) {
+        if world.id() != self.world_id {
+            panic!("Attempted to use {} with a mismatched World. QueryStates can only be used with the World they were created from.",
+                std::any::type_name::<Self>());
+        }
+    }
+
     pub fn new_archetype(&mut self, archetype: &Archetype) {
         if self.fetch_state.matches_archetype(archetype)
             && self.filter_state.matches_archetype(archetype)
@@ -129,6 +134,27 @@ where
         unsafe { self.get_unchecked(world, entity) }
     }
 
+    #[inline]
+    pub fn get_manual<'w>(
+        &self,
+        world: &'w World,
+        entity: Entity,
+    ) -> Result<<Q::Fetch as Fetch<'w>>::Item, QueryEntityError>
+    where
+        Q::Fetch: ReadOnlyFetch,
+    {
+        self.validate_world(world);
+        // SAFETY: query is read only and world is validated
+        unsafe {
+            self.get_unchecked_manual(
+                world,
+                entity,
+                world.last_change_tick(),
+                world.read_change_tick(),
+            )
+        }
+    }
+
     #[inline]
     pub fn get_mut<'w>(
         &mut self,
@@ -149,7 +175,7 @@ where
         world: &'w World,
         entity: Entity,
     ) -> Result<<Q::Fetch as Fetch<'w>>::Item, QueryEntityError> {
-        self.validate_world_and_update_archetypes(world);
+        self.update_archetypes(world);
         self.get_unchecked_manual(
             world,
             entity,
@@ -202,6 +228,18 @@ where
         unsafe { self.iter_unchecked(world) }
     }
 
+    #[inline]
+    pub fn iter_manual<'w, 's>(&'s self, world: &'w World) -> QueryIter<'w, 's, Q, F>
+    where
+        Q::Fetch: ReadOnlyFetch,
+    {
+        self.validate_world(world);
+        // SAFETY: query is read only and world is validated
+        unsafe {
+            self.iter_unchecked_manual(world, world.last_change_tick(), world.read_change_tick())
+        }
+    }
+
     #[inline]
     pub fn iter_mut<'w, 's>(&'s mut self, world: &'w mut World) -> QueryIter<'w, 's, Q, F> {
         // SAFETY: query has unique world access
@@ -238,7 +276,7 @@ where
         &'s mut self,
         world: &'w World,
     ) -> QueryIter<'w, 's, Q, F> {
-        self.validate_world_and_update_archetypes(world);
+        self.update_archetypes(world);
         self.iter_unchecked_manual(world, world.last_change_tick(), world.read_change_tick())
     }
 
@@ -251,7 +289,7 @@ where
         &'s mut self,
         world: &'w World,
     ) -> QueryCombinationIter<'w, 's, Q, F, K> {
-        self.validate_world_and_update_archetypes(world);
+        self.update_archetypes(world);
         self.iter_combinations_unchecked_manual(
             world,
             world.last_change_tick(),
@@ -325,7 +363,7 @@ where
         world: &'w World,
         func: impl FnMut(<Q::Fetch as Fetch<'w>>::Item),
     ) {
-        self.validate_world_and_update_archetypes(world);
+        self.update_archetypes(world);
         self.for_each_unchecked_manual(
             world,
             func,
@@ -376,7 +414,7 @@ where
         batch_size: usize,
         func: impl Fn(<Q::Fetch as Fetch<'w>>::Item) + Send + Sync + Clone,
     ) {
-        self.validate_world_and_update_archetypes(world);
+        self.update_archetypes(world);
         self.par_for_each_unchecked_manual(
             world,
             task_pool,

crates/bevy_ecs/src/storage/sparse_set.rs

@@ -108,7 +108,7 @@ impl ComponentSparseSet {
 
     pub fn clear(&mut self) {
         self.dense.clear();
-        self.ticks.get_mut().clear();
+        self.ticks.clear();
         self.entities.clear();
         self.sparse.clear();
     }

crates/bevy_ecs/src/storage/table.rs

@@ -181,7 +181,7 @@ impl Column {
 
     pub fn clear(&mut self) {
         self.data.clear();
-        self.ticks.get_mut().clear();
+        self.ticks.clear();
     }
 
     #[inline]

crates/bevy_ecs/src/system/commands/mod.rs

@@ -58,6 +58,16 @@ impl<'a> Commands<'a> {
         }
     }
 
+    pub fn get_or_spawn(&mut self, entity: Entity) -> EntityCommands<'a, '_> {
+        self.add(GetOrSpawn {
+            entity,
+        });
+        EntityCommands {
+            entity,
+            commands: self,
+        }
+    }
+
     // TODO: this is a hack to work around the "multiple worlds" limitations:
     // Right now Commands must allocate entities from their "scheduled" world, but Commands might be applied to other worlds,
     // such as the "render world"
@@ -278,6 +288,17 @@ where
     }
 }
 
+pub struct GetOrSpawn {
+    entity: Entity,
+}
+
+impl Command for GetOrSpawn
+{
+    fn write(self: Box<Self>, world: &mut World) {
+        world.get_or_spawn(self.entity);
+    }
+}
+
 pub struct SpawnBatch<I>
 where
     I: IntoIterator,

crates/bevy_ecs/src/world/mod.rs

@@ -16,7 +16,7 @@ use crate::{
         Component, ComponentDescriptor, ComponentId, ComponentTicks, Components, ComponentsError,
         StorageType,
     },
-    entity::{Entities, Entity},
+    entity::{AllocAtWithoutReplacement, Entities, Entity},
     query::{FilterFetch, QueryState, WorldQuery},
     storage::{Column, SparseSet, Storages},
 };
@@ -94,6 +94,13 @@ impl World {
         &self.entities
     }
 
+    /// Retrieves this world's [Entities] collection mutably
+    #[inline]
+    pub fn entities_mut(&mut self) -> &mut Entities {
+        &mut self.entities
+    }
+
+
     /// Retrieves this world's [Archetypes] collection
     #[inline]
     pub fn archetypes(&self) -> &Archetypes {
@@ -215,6 +222,24 @@ impl World {
         self.get_entity_mut(entity).expect("Entity does not exist")
     }
 
+    /// Returns an EntityMut for an existing entity or creates one if it doesn't exist.
+    /// This will return `None` if the entity exists with a different generation.
+    #[inline]
+    pub fn get_or_spawn(&mut self, entity: Entity) -> Option<EntityMut> {
+        self.flush();
+        match self.entities.alloc_at_without_replacement(entity) {
+            AllocAtWithoutReplacement::Exists(location) => {
+                // SAFE: `entity` exists and `location` is that entity's location
+                Some(unsafe { EntityMut::new(self, entity, location) })
+            }
+            AllocAtWithoutReplacement::DidNotExist => {
+                // SAFE: entity was just allocated
+                Some(unsafe { self.spawn_at_internal(entity) })
+            }
+            AllocAtWithoutReplacement::ExistsWithWrongGeneration => None,
+        }
+    }
+
     /// Retrieves an [EntityRef] that exposes read-only operations for the given `entity`.
     /// Returns [None] if the `entity` does not exist. Use [World::entity] if you don't want
     /// to unwrap the [EntityRef] yourself.
@@ -293,8 +318,14 @@ impl World {
     pub fn spawn(&mut self) -> EntityMut {
         self.flush();
         let entity = self.entities.alloc();
+        // SAFE: entity was just allocated
+        unsafe { self.spawn_at_internal(entity) }
+    }
+
+    /// # Safety
+    /// must be called on an entity that was just allocated
+    unsafe fn spawn_at_internal(&mut self, entity: Entity) -> EntityMut {
         let archetype = self.archetypes.empty_mut();
-        unsafe {
         // PERF: consider avoiding allocating entities in the empty archetype unless needed
         let table_row = self.storages.tables[archetype.table_id()].allocate(entity);
         // SAFE: no components are allocated by archetype.allocate() because the archetype is
@@ -307,7 +338,6 @@ impl World {
             .location = location;
         EntityMut::new(self, entity, location)
     }
-    }
 
     /// Spawns a batch of entities with the same component [Bundle] type. Takes a given [Bundle]
     /// iterator and returns a corresponding [Entity] iterator.
@@ -878,6 +908,7 @@ impl World {
         unsafe {
             let table = &mut self.storages.tables[empty_archetype.table_id()];
             // PERF: consider pre-allocating space for flushed entities
+            // SAFE: entity is set to a valid location
             self.entities.flush(|entity, location| {
                 // SAFE: no components are allocated by archetype.allocate() because the archetype
                 // is empty

crates/bevy_internal/Cargo.toml

@@ -68,6 +68,7 @@ bevy_tasks = { path = "../bevy_tasks", version = "0.5.0" }
 bevy_audio = { path = "../bevy_audio", optional = true, version = "0.5.0" }
 bevy_gltf = { path = "../bevy_gltf", optional = true, version = "0.5.0" }
 bevy_pbr = { path = "../bevy_pbr", optional = true, version = "0.5.0" }
+bevy_pbr2 = { path = "../../pipelined/bevy_pbr2", optional = true, version = "0.5.0" }
 bevy_render = { path = "../bevy_render", optional = true, version = "0.5.0" }
 bevy_render2 = { path = "../../pipelined/bevy_render2", optional = true, version = "0.5.0" }
 bevy_dynamic_plugin = { path = "../bevy_dynamic_plugin", optional = true, version = "0.5.0" }

crates/bevy_internal/src/default_plugins.rs

@@ -119,7 +119,10 @@ impl PluginGroup for PipelinedDefaultPlugins {
         group.add(bevy_asset::AssetPlugin::default());
 
         #[cfg(feature = "bevy_render2")]
+        {
             group.add(bevy_render2::RenderPlugin::default());
+            group.add(bevy_render2::core_pipeline::CorePipelinePlugin::default());
+        }
 
         #[cfg(feature = "bevy_winit")]
         group.add(bevy_winit::WinitPlugin::default());
@@ -129,5 +132,8 @@ impl PluginGroup for PipelinedDefaultPlugins {
 
         #[cfg(feature = "bevy_sprite2")]
         group.add(bevy_sprite2::SpritePlugin::default());
+
+        #[cfg(feature = "bevy_pbr2")]
+        group.add(bevy_pbr2::PbrPlugin::default());
     }
 }

crates/bevy_internal/src/lib.rs

@@ -99,6 +99,12 @@ pub mod pbr {
     pub use bevy_pbr::*;
 }
 
+#[cfg(feature = "bevy_pbr2")]
+pub mod pbr2 {
+    //! Physically based rendering.
+    pub use bevy_pbr2::*;
+}
+
 #[cfg(feature = "bevy_render")]
 pub mod render {
     //! Cameras, meshes, textures, shaders, and pipelines.

crates/bevy_log/src/lib.rs

@@ -33,7 +33,7 @@ use tracing_subscriber::{prelude::*, registry::Registry, EnvFilter};
 /// # use bevy_log::LogSettings;
 /// # use bevy_utils::tracing::Level;
 /// fn main() {
-///     App::build()
+///     App::new()
 ///         .insert_resource(LogSettings {
 ///             level: Level::DEBUG,
 ///             filter: "wgpu=error,bevy_render=info".to_string(),
@@ -53,7 +53,7 @@ use tracing_subscriber::{prelude::*, registry::Registry, EnvFilter};
 /// # use bevy_app::App;
 /// # use bevy_log::LogPlugin;
 /// fn main() {
-///     App::build()
+///     App::new()
 ///         .add_plugins_with(DefaultPlugins, |group| group.disable::<LogPlugin>())
 ///         .run();
 /// }

crates/bevy_render/src/lib.rs

@@ -102,7 +102,7 @@ impl Default for RenderPlugin {
 }
 
 impl Plugin for RenderPlugin {
-    fn build(&self, app: &mut AppBuilder) {
+    fn build(&self, app: &mut App) {
         #[cfg(any(
             feature = "png",
             feature = "dds",

crates/bevy_window/Cargo.toml

@@ -18,6 +18,7 @@ bevy_app = { path = "../bevy_app", version = "0.5.0" }
 bevy_ecs = { path = "../bevy_ecs", version = "0.5.0" }
 bevy_math = { path = "../bevy_math", version = "0.5.0" }
 bevy_utils = { path = "../bevy_utils", version = "0.5.0" }
+raw-window-handle = "0.3.0"
 
 # other
 

crates/bevy_window/src/lib.rs

@@ -1,9 +1,10 @@
 mod event;
+mod raw_window_handle;
 mod system;
 mod window;
 mod windows;
 
-use bevy_ecs::system::IntoSystem;
+pub use crate::raw_window_handle::*;
 pub use event::*;
 pub use system::*;
 pub use window::*;
@@ -18,6 +19,7 @@ pub mod prelude {
 }
 
 use bevy_app::{prelude::*, Events};
+use bevy_ecs::system::IntoSystem;
 
 pub struct WindowPlugin {
     pub add_primary_window: bool,

crates/bevy_window/src/raw_window_handle.rs

@@ -0,0 +1,37 @@
+use raw_window_handle::{HasRawWindowHandle, RawWindowHandle};
+
+/// This wrapper exist to enable safely passing a [`RawWindowHandle`] across threads. Extracting the handle
+/// is still an unsafe operation, so the caller must still validate that using the raw handle is safe for a given context.
+#[derive(Debug, Clone)]
+pub struct RawWindowHandleWrapper(RawWindowHandle);
+
+impl RawWindowHandleWrapper {
+    pub(crate) fn new(handle: RawWindowHandle) -> Self {
+        Self(handle)
+    }
+
+    /// # Safety
+    /// This returns a [`HasRawWindowHandle`] impl, which exposes [`RawWindowHandle`]. Some platforms
+    /// have constraints on where/how this handle can be used. For example, some platforms don't support doing window
+    /// operations off of the main thread. The caller must ensure the [`RawWindowHandle`] is only used in valid contexts.
+    pub unsafe fn get_handle(&self) -> HasRawWindowHandleWrapper {
+        HasRawWindowHandleWrapper(self.0.clone())
+    }
+}
+
+// SAFE: RawWindowHandle is just a normal "raw pointer", which doesn't impl Send/Sync. However the pointer is only
+// exposed via an unsafe method that forces the user to make a call for a given platform. (ex: some platforms don't
+// support doing window operations off of the main thread).
+// A recommendation for this pattern (and more context) is available here:
+// https://github.com/rust-windowing/raw-window-handle/issues/59
+unsafe impl Send for RawWindowHandleWrapper {}
+unsafe impl Sync for RawWindowHandleWrapper {}
+
+pub struct HasRawWindowHandleWrapper(RawWindowHandle);
+
+// SAFE: the caller has validated that this is a valid context to get RawWindowHandle
+unsafe impl HasRawWindowHandle for HasRawWindowHandleWrapper {
+    fn raw_window_handle(&self) -> RawWindowHandle {
+        self.0.clone()
+    }
+}

crates/bevy_window/src/window.rs

@@ -1,5 +1,6 @@
 use bevy_math::{IVec2, Vec2};
 use bevy_utils::{tracing::warn, Uuid};
+use raw_window_handle::RawWindowHandle;
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 pub struct WindowId(Uuid);
@@ -20,6 +21,8 @@ impl WindowId {
 
 use std::fmt;
 
+use crate::raw_window_handle::RawWindowHandleWrapper;
+
 impl fmt::Display for WindowId {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.0.to_simple().fmt(f)
@@ -123,6 +126,7 @@ pub struct Window {
     cursor_visible: bool,
     cursor_locked: bool,
     cursor_position: Option<Vec2>,
+    raw_window_handle: RawWindowHandleWrapper,
     focused: bool,
     mode: WindowMode,
     #[cfg(target_arch = "wasm32")]
@@ -198,6 +202,7 @@ impl Window {
         physical_height: u32,
         scale_factor: f64,
         position: Option<IVec2>,
+        raw_window_handle: RawWindowHandle,
     ) -> Self {
         Window {
             id,
@@ -216,6 +221,7 @@ impl Window {
             cursor_visible: window_descriptor.cursor_visible,
             cursor_locked: window_descriptor.cursor_locked,
             cursor_position: None,
+            raw_window_handle: RawWindowHandleWrapper::new(raw_window_handle),
             focused: true,
             mode: window_descriptor.mode,
             #[cfg(target_arch = "wasm32")]
@@ -511,6 +517,10 @@ impl Window {
     pub fn is_focused(&self) -> bool {
         self.focused
     }
+
+    pub fn raw_window_handle(&self) -> RawWindowHandleWrapper {
+        self.raw_window_handle.clone()
+    }
 }
 
 #[derive(Debug, Clone)]

crates/bevy_winit/Cargo.toml

@@ -27,6 +27,7 @@ bevy_utils = { path = "../bevy_utils", version = "0.5.0" }
 
 # other
 winit = { version = "0.25.0", default-features = false }
+raw-window-handle = "0.3.0"
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 winit = { version = "0.25.0", features = ["web-sys"], default-features = false }

crates/bevy_winit/src/winit_windows.rs

@@ -1,6 +1,7 @@
 use bevy_math::IVec2;
 use bevy_utils::HashMap;
 use bevy_window::{Window, WindowDescriptor, WindowId, WindowMode};
+use raw_window_handle::HasRawWindowHandle;
 use winit::dpi::LogicalSize;
 
 #[derive(Debug, Default)]
@@ -137,6 +138,7 @@ impl WinitWindows {
             .map(|position| IVec2::new(position.x, position.y));
         let inner_size = winit_window.inner_size();
         let scale_factor = winit_window.scale_factor();
+        let raw_window_handle = winit_window.raw_window_handle();
         self.windows.insert(winit_window.id(), winit_window);
         Window::new(
             window_id,
@@ -145,6 +147,7 @@ impl WinitWindows {
             inner_size.height,
             scale_factor,
             position,
+            raw_window_handle,
         )
     }
 

crates/crevice/Cargo.toml

@@ -13,15 +13,19 @@ license = "MIT OR Apache-2.0"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[features]
+default = ["std"]
+std = []
+
 [dependencies]
-crevice-derive = "0.6.0"
+crevice-derive = { version = "0.6.0", path = "crevice-derive" }
 
 bytemuck = "1.4.1"
-mint = { version = "0.5.5", optional = true }
+mint = "0.5.5"
 glam = "0.15.1"
 
 [dev-dependencies]
 cgmath = { version = "0.17.0", features = ["mint"] }
 insta = "0.16.1"
 type-layout = { version = "0.2.0", features = ["serde1"] }
-crevice-derive = { version = "0.6.0", features = ["test_type_layout"] }
+crevice-derive = { version = "0.6.0", path = "crevice-derive" }

crates/crevice/crevice-derive/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "crevice-derive"
+description = "Derive crate for the 'crevice' crate"
+version = "0.6.0"
+edition = "2018"
+authors = ["Lucien Greathouse <me@lpghatguy.com>"]
+documentation = "https://docs.rs/crevice-derive"
+homepage = "https://github.com/LPGhatguy/crevice"
+repository = "https://github.com/LPGhatguy/crevice"
+license = "MIT OR Apache-2.0"
+
+[features]
+# Feature used for testing; enables type_layout derive on types.
+# Requires crate using derive to depend on type_layout as well.
+test_type_layout = []
+
+[lib]
+proc-macro = true
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+syn = "1.0.40"
+quote = "1.0.7"
+proc-macro2 = "1.0.21"

crates/crevice/crevice-derive/src/lib.rs

@@ -0,0 +1,301 @@
+use proc_macro::TokenStream as CompilerTokenStream;
+
+use proc_macro2::{Span, TokenStream};
+use quote::{format_ident, quote};
+use syn::{parse_macro_input, parse_quote, Data, DeriveInput, Fields, Ident, Path};
+
+#[proc_macro_derive(AsStd140)]
+pub fn derive_as_std140(input: CompilerTokenStream) -> CompilerTokenStream {
+    let input = parse_macro_input!(input as DeriveInput);
+    let expanded = EmitOptions::new("Std140", "std140", 16).emit(input);
+
+    CompilerTokenStream::from(expanded)
+}
+
+#[proc_macro_derive(AsStd430)]
+pub fn derive_as_std430(input: CompilerTokenStream) -> CompilerTokenStream {
+    let input = parse_macro_input!(input as DeriveInput);
+    let expanded = EmitOptions::new("Std430", "std430", 0).emit(input);
+
+    CompilerTokenStream::from(expanded)
+}
+
+struct EmitOptions {
+    /// The Rust-friendly name of the layout, like Std140.
+    layout_name: Ident,
+
+    /// The minimum alignment for a struct in this layout.
+    min_struct_alignment: usize,
+
+    /// The fully-qualified path to the Crevice module containing everything for
+    /// this layout.
+    mod_path: Path,
+
+    /// The fully-qualified path to the trait defining a type in this layout.
+    trait_path: Path,
+
+    /// The fully-qualified path to the trait implemented for types that can be
+    /// converted into this layout, like AsStd140.
+    as_trait_path: Path,
+
+    /// The name of the associated type contained in AsTrait.
+    as_trait_assoc: Ident,
+
+    /// The name of the method used to convert from AsTrait to Trait.
+    as_trait_method: Ident,
+
+    // The name of the method used to convert from Trait to AsTrait.
+    from_trait_method: Ident,
+
+    /// The name of the struct used for Padded type.
+    padded_name: Ident,
+}
+
+impl EmitOptions {
+    fn new(layout_name: &'static str, mod_name: &'static str, min_struct_alignment: usize) -> Self {
+        let mod_name = Ident::new(mod_name, Span::call_site());
+        let layout_name = Ident::new(layout_name, Span::call_site());
+
+        let mod_path = parse_quote!(::crevice::#mod_name);
+        let trait_path = parse_quote!(#mod_path::#layout_name);
+
+        let as_trait_name = format_ident!("As{}", layout_name);
+        let as_trait_path = parse_quote!(#mod_path::#as_trait_name);
+        let as_trait_assoc = format_ident!("{}Type", layout_name);
+        let as_trait_method = format_ident!("as_{}", mod_name);
+        let from_trait_method = format_ident!("from_{}", mod_name);
+
+        let padded_name = format_ident!("{}Padded", layout_name);
+
+        Self {
+            layout_name,
+            min_struct_alignment,
+
+            mod_path,
+            trait_path,
+            as_trait_path,
+            as_trait_assoc,
+            as_trait_method,
+            from_trait_method,
+
+            padded_name,
+        }
+    }
+
+    fn emit(&self, input: DeriveInput) -> TokenStream {
+        let min_struct_alignment = self.min_struct_alignment;
+        let layout_name = &self.layout_name;
+        let mod_path = &self.mod_path;
+        let trait_path = &self.trait_path;
+        let as_trait_path = &self.as_trait_path;
+        let as_trait_assoc = &self.as_trait_assoc;
+        let as_trait_method = &self.as_trait_method;
+        let from_trait_method = &self.from_trait_method;
+        let padded_name = &self.padded_name;
+
+        let visibility = input.vis;
+
+        let name = input.ident;
+        let generated_name = format_ident!("{}{}", layout_name, name);
+        let alignment_mod_name = format_ident!("{}{}Alignment", layout_name, name);
+
+        let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
+
+        let fields = match &input.data {
+            Data::Struct(data) => match &data.fields {
+                Fields::Named(fields) => fields,
+                Fields::Unnamed(_) => panic!("Tuple structs are not supported"),
+                Fields::Unit => panic!("Unit structs are not supported"),
+            },
+            Data::Enum(_) | Data::Union(_) => panic!("Only structs are supported"),
+        };
+
+        // Generate the names we'll use for calculating alignment of each field.
+        // Each name will turn into a const fn that's invoked to compute the
+        // size of a padding array before each field.
+        let align_names: Vec<_> = fields
+            .named
+            .iter()
+            .map(|field| format_ident!("_{}_align", field.ident.as_ref().unwrap()))
+            .collect();
+
+        // Generate one function per field that is used to apply alignment
+        // padding. Each function invokes all previous functions to calculate
+        // the total offset into the struct for the current field, then aligns
+        // up to the nearest multiple of alignment.
+        let alignment_calculators: Vec<_> = fields
+            .named
+            .iter()
+            .enumerate()
+            .map(|(index, field)| {
+                let align_name = &align_names[index];
+
+                let offset_accumulation =
+                    fields
+                        .named
+                        .iter()
+                        .zip(&align_names)
+                        .take(index)
+                        .map(|(field, align_name)| {
+                            let field_ty = &field.ty;
+                            quote! {
+                                offset += #align_name();
+                                offset += ::core::mem::size_of::<<#field_ty as #as_trait_path>::#as_trait_assoc>();
+                            }
+                        });
+
+                let pad_at_end = index
+                    .checked_sub(1)
+                    .map_or(quote!{0usize}, |prev_index|{
+                        let field = &fields.named[prev_index];
+                        let field_ty = &field.ty;
+                        quote! {
+                            if <<#field_ty as #as_trait_path>::#as_trait_assoc as #mod_path::#layout_name>::PAD_AT_END {
+                                <<#field_ty as #as_trait_path>::#as_trait_assoc as #mod_path::#layout_name>::ALIGNMENT
+                            }
+                            else {
+                                0usize
+                            }
+                        }
+                    });
+
+                let field_ty = &field.ty;
+
+                quote! {
+                    pub const fn #align_name() -> usize {
+                        let mut offset = 0;
+                        #( #offset_accumulation )*
+
+                        ::crevice::internal::align_offset(
+                            offset,
+                            ::crevice::internal::max(
+                                <<#field_ty as #as_trait_path>::#as_trait_assoc as #mod_path::#layout_name>::ALIGNMENT,
+                                #pad_at_end
+                            )
+                        )
+                    }
+                }
+            })
+            .collect();
+
+        // Generate the struct fields that will be present in the generated
+        // struct. Each field in the original struct turns into two fields in
+        // the generated struct:
+        //
+        // * Alignment, a byte array whose size is computed from #align_name().
+        // * Data, the layout-specific version of the original field.
+        let generated_fields: Vec<_> = fields
+            .named
+            .iter()
+            .zip(&align_names)
+            .map(|(field, align_name)| {
+                let field_ty = &field.ty;
+                let field_name = field.ident.as_ref().unwrap();
+
+                quote! {
+                    #align_name: [u8; #alignment_mod_name::#align_name()],
+                    #field_name: <#field_ty as #as_trait_path>::#as_trait_assoc,
+                }
+            })
+            .collect();
+
+        // Generate an initializer for each field in the original struct.
+        // Alignment fields are filled in with zeroes using struct update
+        // syntax.
+        let field_initializers: Vec<_> = fields
+            .named
+            .iter()
+            .map(|field| {
+                let field_name = field.ident.as_ref().unwrap();
+
+                quote!(#field_name: self.#field_name.#as_trait_method())
+            })
+            .collect();
+
+        let field_unwrappers: Vec<_> = fields
+            .named
+            .iter()
+            .map(|field|{
+                let field_name = field.ident.as_ref().unwrap();
+                let field_ty = &field.ty;
+                quote!(#field_name: <#field_ty as #as_trait_path>::#from_trait_method(value.#field_name))
+            })
+            .collect();
+
+        // This fold builds up an expression that finds the maximum alignment out of
+        // all of the fields in the struct. For this struct:
+        //
+        // struct Foo { a: ty1, b: ty2 }
+        //
+        // ...we should generate an expression like this:
+        //
+        // max(ty2_align, max(ty1_align, min_align))
+        let struct_alignment = fields.named.iter().fold(
+            quote!(#min_struct_alignment),
+            |last, field| {
+                let field_ty = &field.ty;
+
+                quote! {
+                    ::crevice::internal::max(
+                        <<#field_ty as #as_trait_path>::#as_trait_assoc as #trait_path>::ALIGNMENT,
+                        #last,
+                    )
+                }
+            },
+        );
+
+        // For testing purposes, we can optionally generate type layout
+        // information using the type-layout crate.
+        let type_layout_derive = if cfg!(feature = "test_type_layout") {
+            quote!(#[derive(::type_layout::TypeLayout)])
+        } else {
+            quote!()
+        };
+
+        quote! {
+            #[allow(non_snake_case)]
+            mod #alignment_mod_name {
+                use super::*;
+
+                #( #alignment_calculators )*
+            }
+
+            #[derive(Debug, Clone, Copy)]
+            #type_layout_derive
+            #[repr(C)]
+            #visibility struct #generated_name #ty_generics #where_clause {
+                #( #generated_fields )*
+            }
+
+            unsafe impl #impl_generics ::crevice::internal::bytemuck::Zeroable for #generated_name #ty_generics #where_clause {}
+            unsafe impl #impl_generics ::crevice::internal::bytemuck::Pod for #generated_name #ty_generics #where_clause {}
+
+            unsafe impl #impl_generics #mod_path::#layout_name for #generated_name #ty_generics #where_clause {
+                const ALIGNMENT: usize = #struct_alignment;
+                const PAD_AT_END: bool = true;
+                type Padded = #mod_path::#padded_name<Self, {::crevice::internal::align_offset(
+                    ::core::mem::size_of::<#generated_name>(),
+                    #struct_alignment
+                )}>;
+            }
+
+            impl #impl_generics #as_trait_path for #name #ty_generics #where_clause {
+                type #as_trait_assoc = #generated_name;
+
+                fn #as_trait_method(&self) -> Self::#as_trait_assoc {
+                    Self::#as_trait_assoc {
+                        #( #field_initializers, )*
+
+                        ..::crevice::internal::bytemuck::Zeroable::zeroed()
+                    }
+                }
+
+                fn #from_trait_method(value: Self::#as_trait_assoc) -> Self {
+                    Self {
+                        #( #field_unwrappers, )*
+                    }
+                }
+            }
+        }
+    }
+}

crates/crevice/src/glam.rs

@@ -16,6 +16,10 @@ macro_rules! glam_vectors {
                         )*
                     }
                 }
+
+                fn from_std140(value: Self::Std140Type) -> Self {
+                    Self::new($(value.$field,)*)
+                }
             }
 
             impl AsStd430 for $glam_ty {
@@ -28,6 +32,10 @@ macro_rules! glam_vectors {
                         )*
                     }
                 }
+
+                fn from_std430(value: Self::Std430Type) -> Self {
+                    Self::new($(value.$field,)*)
+                }
             }
         )*
     };
@@ -53,6 +61,14 @@ macro_rules! glam_matrices {
                         ..Zeroable::zeroed()
                     }
                 }
+
+                fn from_std140(value: Self::Std140Type) -> Self {
+                    Self::from_cols(
+                        $(
+                            <_ as AsStd140>::from_std140(value.$field),
+                        )*
+                    )
+                }
             }
 
             impl AsStd430 for $glam_ty {
@@ -66,6 +82,14 @@ macro_rules! glam_matrices {
                         ..Zeroable::zeroed()
                     }
                 }
+
+                fn from_std430(value: Self::Std430Type) -> Self {
+                    Self::from_cols(
+                        $(
+                            <_ as AsStd430>::from_std430(value.$field),
+                        )*
+                    )
+                }
             }
         )*
     };

crates/crevice/src/lib.rs

@@ -129,6 +129,7 @@ Crevice supports Rust 1.46.0 and newer due to use of new `const fn` features.
 */
 
 #![deny(missing_docs)]
+#![cfg_attr(not(feature = "std"), no_std)]
 
 pub mod std140;
 pub mod std430;
@@ -136,7 +137,6 @@ pub mod std430;
 #[doc(hidden)]
 pub mod internal;
 
-#[cfg(feature = "mint")]
 mod mint;
 
 mod glam;

crates/crevice/src/mint.rs

@@ -16,6 +16,14 @@ macro_rules! mint_vectors {
                         )*
                     }
                 }
+
+                fn from_std140(value: Self::Std140Type) -> Self {
+                    Self {
+                        $(
+                            $field: value.$field,
+                        )*
+                    }
+                }
             }
 
             impl AsStd430 for $mint_ty {
@@ -28,6 +36,14 @@ macro_rules! mint_vectors {
                         )*
                     }
                 }
+
+                fn from_std430(value: Self::Std430Type) -> Self {
+                    Self {
+                        $(
+                            $field: value.$field,
+                        )*
+                    }
+                }
             }
         )*
     };
@@ -37,6 +53,22 @@ mint_vectors! {
     mint::Vector2<f32>, Vec2, (x, y),
     mint::Vector3<f32>, Vec3, (x, y, z),
     mint::Vector4<f32>, Vec4, (x, y, z, w),
+
+    mint::Vector2<i32>, IVec2, (x, y),
+    mint::Vector3<i32>, IVec3, (x, y, z),
+    mint::Vector4<i32>, IVec4, (x, y, z, w),
+
+    mint::Vector2<u32>, UVec2, (x, y),
+    mint::Vector3<u32>, UVec3, (x, y, z),
+    mint::Vector4<u32>, UVec4, (x, y, z, w),
+
+    mint::Vector2<bool>, BVec2, (x, y),
+    mint::Vector3<bool>, BVec3, (x, y, z),
+    mint::Vector4<bool>, BVec4, (x, y, z, w),
+
+    mint::Vector2<f64>, DVec2, (x, y),
+    mint::Vector3<f64>, DVec3, (x, y, z),
+    mint::Vector4<f64>, DVec4, (x, y, z, w),
 }
 
 macro_rules! mint_matrices {
@@ -53,6 +85,14 @@ macro_rules! mint_matrices {
                         ..Zeroable::zeroed()
                     }
                 }
+
+                fn from_std140(value: Self::Std140Type) -> Self {
+                    Self {
+                        $(
+                            $field: <_ as AsStd140>::from_std140(value.$field),
+                        )*
+                    }
+                }
             }
 
             impl AsStd430 for $mint_ty {
@@ -66,6 +106,14 @@ macro_rules! mint_matrices {
                         ..Zeroable::zeroed()
                     }
                 }
+
+                fn from_std430(value: Self::Std430Type) -> Self {
+                    Self {
+                        $(
+                            $field: <_ as AsStd430>::from_std430(value.$field),
+                        )*
+                    }
+                }
             }
         )*
     };
@@ -75,4 +123,8 @@ mint_matrices! {
     mint::ColumnMatrix2<f32>, Mat2, (x, y),
     mint::ColumnMatrix3<f32>, Mat3, (x, y, z),
     mint::ColumnMatrix4<f32>, Mat4, (x, y, z, w),
+
+    mint::ColumnMatrix2<f64>, DMat2, (x, y),
+    mint::ColumnMatrix3<f64>, DMat3, (x, y, z),
+    mint::ColumnMatrix4<f64>, DMat4, (x, y, z, w),
 }

crates/crevice/src/std140.rs

@@ -5,12 +5,14 @@ mod dynamic_uniform;
 mod primitives;
 mod sizer;
 mod traits;
+#[cfg(feature = "std")]
 mod writer;
 
 pub use self::dynamic_uniform::*;
 pub use self::primitives::*;
 pub use self::sizer::*;
 pub use self::traits::*;
+#[cfg(feature = "std")]
 pub use self::writer::*;
 
 pub use crevice_derive::AsStd140;

crates/crevice/src/std140/dynamic_uniform.rs

@@ -1,6 +1,7 @@
 use bytemuck::{Pod, Zeroable};
 
-use crate::internal::max;
+#[allow(unused_imports)]
+use crate::internal::{align_offset, max};
 use crate::std140::{AsStd140, Std140};
 
 /// Wrapper type that aligns the inner type to at least 256 bytes.
@@ -15,6 +16,10 @@ impl<T: AsStd140> AsStd140 for DynamicUniform<T> {
     fn as_std140(&self) -> Self::Std140Type {
         DynamicUniformStd140(self.0.as_std140())
     }
+
+    fn from_std140(value: Self::Std140Type) -> Self {
+        DynamicUniform(<T as AsStd140>::from_std140(value.0))
+    }
 }
 
 /// std140 variant of [`DynamicUniform`].
@@ -24,6 +29,13 @@ pub struct DynamicUniformStd140<T>(T);
 
 unsafe impl<T: Std140> Std140 for DynamicUniformStd140<T> {
     const ALIGNMENT: usize = max(256, T::ALIGNMENT);
+    #[cfg(const_evaluatable_checked)]
+    type Padded = crate::std140::Std140Padded<
+        Self,
+        { align_offset(core::mem::size_of::<T>(), max(256, T::ALIGNMENT)) },
+    >;
+    #[cfg(not(const_evaluatable_checked))]
+    type Padded = crate::std140::InvalidPadded;
 }
 
 unsafe impl<T: Zeroable> Zeroable for DynamicUniformStd140<T> {}

crates/crevice/src/std140/primitives.rs

@@ -1,21 +1,28 @@
 use bytemuck::{Pod, Zeroable};
 
-use crate::std140::Std140;
+use crate::std140::{Std140, Std140Padded};
+
+use crate::internal::{align_offset, max};
+use core::mem::size_of;
 
 unsafe impl Std140 for f32 {
     const ALIGNMENT: usize = 4;
+    type Padded = Std140Padded<Self, 12>;
 }
 
 unsafe impl Std140 for f64 {
     const ALIGNMENT: usize = 8;
+    type Padded = Std140Padded<Self, 8>;
 }
 
 unsafe impl Std140 for i32 {
     const ALIGNMENT: usize = 4;
+    type Padded = Std140Padded<Self, 12>;
 }
 
 unsafe impl Std140 for u32 {
     const ALIGNMENT: usize = 4;
+    type Padded = Std140Padded<Self, 12>;
 }
 
 macro_rules! vectors {
@@ -37,6 +44,7 @@ macro_rules! vectors {
 
             unsafe impl Std140 for $name {
                 const ALIGNMENT: usize = $align;
+                type Padded = Std140Padded<Self, {align_offset(size_of::<$name>(), max(16, $align))}>;
             }
         )+
     };
@@ -87,6 +95,9 @@ macro_rules! matrices {
 
             unsafe impl Std140 for $name {
                 const ALIGNMENT: usize = $align;
+                /// Matrices are technically arrays of primitives, and as such require pad at end.
+                const PAD_AT_END: bool = true;
+                type Padded = Std140Padded<Self, {align_offset(size_of::<$name>(), max(16, $align))}>;
             }
         )+
     };

crates/crevice/src/std140/sizer.rs

@@ -1,4 +1,4 @@
-use std::mem::size_of;
+use core::mem::size_of;
 
 use crate::internal::align_offset;
 use crate::std140::{AsStd140, Std140};

crates/crevice/src/std140/traits.rs

@@ -1,8 +1,10 @@
+use core::mem::{size_of, MaybeUninit};
+#[cfg(feature = "std")]
 use std::io::{self, Write};
-use std::mem::size_of;
 
 use bytemuck::{bytes_of, Pod, Zeroable};
 
+#[cfg(feature = "std")]
 use crate::std140::Writer;
 
 /// Trait implemented for all `std140` primitives. Generally should not be
@@ -15,6 +17,15 @@ pub unsafe trait Std140: Copy + Zeroable + Pod {
     /// control and zero their padding bytes, making converting them to and from
     /// slices safe.
     const ALIGNMENT: usize;
+    /// Whether this type requires a padding at the end (ie, is a struct or an array
+    /// of primitives).
+    /// See https://www.khronos.org/registry/OpenGL/specs/gl/glspec45.core.pdf#page=159
+    /// (rule 4 and 9)
+    const PAD_AT_END: bool = false;
+    /// Padded type (Std140Padded specialization)
+    /// The usual implementation is
+    /// type Padded = Std140Padded<Self, {align_offset(size_of::<Self>(), max(16, ALIGNMENT))}>;
+    type Padded: Std140Convertible<Self>;
 
     /// Casts the type to a byte array. Implementors should not override this
     /// method.
@@ -27,9 +38,38 @@ pub unsafe trait Std140: Copy + Zeroable + Pod {
     }
 }
 
+/// Trait specifically for Std140::Padded, implements conversions between padded type and base type.
+pub trait Std140Convertible<T: Std140>: Copy {
+    /// Convert from self to Std140
+    fn into_std140(self) -> T;
+    /// Convert from Std140 to self
+    fn from_std140(_: T) -> Self;
+}
+
+impl<T: Std140> Std140Convertible<T> for T {
+    fn into_std140(self) -> T {
+        self
+    }
+    fn from_std140(also_self: T) -> Self {
+        also_self
+    }
+}
+
+/// Unfortunately, we cannot easily derive padded representation for generic Std140 types.
+/// For now, we'll just use this empty enum with no values.
+#[derive(Copy, Clone)]
+pub enum InvalidPadded {}
+impl<T: Std140> Std140Convertible<T> for InvalidPadded {
+    fn into_std140(self) -> T {
+        unimplemented!()
+    }
+    fn from_std140(_: T) -> Self {
+        unimplemented!()
+    }
+}
 /**
 Trait implemented for all types that can be turned into `std140` values.
-
+*
 This trait can often be `#[derive]`'d instead of manually implementing it. Any
 struct which contains only fields that also implement `AsStd140` can derive
 `AsStd140`.
@@ -80,6 +120,9 @@ pub trait AsStd140 {
     fn std140_size_static() -> usize {
         size_of::<Self::Std140Type>()
     }
+
+    /// Converts from `std140` version of self to self.
+    fn from_std140(val: Self::Std140Type) -> Self;
 }
 
 impl<T> AsStd140 for T
@@ -91,6 +134,75 @@ where
     fn as_std140(&self) -> Self {
         *self
     }
+
+    fn from_std140(x: Self) -> Self {
+        x
+    }
+}
+
+#[doc(hidden)]
+#[derive(Copy, Clone, Debug)]
+pub struct Std140Padded<T: Std140, const PAD: usize> {
+    inner: T,
+    _padding: [u8; PAD],
+}
+
+unsafe impl<T: Std140, const PAD: usize> Zeroable for Std140Padded<T, PAD> {}
+unsafe impl<T: Std140, const PAD: usize> Pod for Std140Padded<T, PAD> {}
+
+impl<T: Std140, const PAD: usize> Std140Convertible<T> for Std140Padded<T, PAD> {
+    fn into_std140(self) -> T {
+        self.inner
+    }
+
+    fn from_std140(inner: T) -> Self {
+        Self {
+            inner,
+            _padding: [0u8; PAD],
+        }
+    }
+}
+
+#[doc(hidden)]
+#[derive(Copy, Clone, Debug)]
+#[repr(transparent)]
+pub struct Std140Array<T: Std140, const N: usize>([T::Padded; N]);
+
+unsafe impl<T: Std140, const N: usize> Zeroable for Std140Array<T, N> where T::Padded: Zeroable {}
+unsafe impl<T: Std140, const N: usize> Pod for Std140Array<T, N> where T::Padded: Pod {}
+unsafe impl<T: Std140, const N: usize> Std140 for Std140Array<T, N>
+where
+    T::Padded: Pod,
+{
+    const ALIGNMENT: usize = crate::internal::max(T::ALIGNMENT, 16);
+    type Padded = Self;
+}
+
+impl<T: AsStd140, const N: usize> AsStd140 for [T; N]
+where
+    <T::Std140Type as Std140>::Padded: Pod,
+{
+    type Std140Type = Std140Array<T::Std140Type, N>;
+    fn as_std140(&self) -> Self::Std140Type {
+        let mut res: [MaybeUninit<<T::Std140Type as Std140>::Padded>; N] =
+            unsafe { MaybeUninit::uninit().assume_init() };
+
+        for i in 0..N {
+            res[i] = MaybeUninit::new(Std140Convertible::from_std140(self[i].as_std140()));
+        }
+
+        unsafe { core::mem::transmute_copy(&res) }
+    }
+
+    fn from_std140(val: Self::Std140Type) -> Self {
+        let mut res: [MaybeUninit<T>; N] = unsafe { MaybeUninit::uninit().assume_init() };
+
+        for i in 0..N {
+            res[i] = MaybeUninit::new(AsStd140::from_std140(val.0[i].into_std140()));
+        }
+
+        unsafe { core::mem::transmute_copy(&res) }
+    }
 }
 
 /// Trait implemented for all types that can be written into a buffer as
@@ -101,6 +213,7 @@ where
 /// `Std140` trait, `WriteStd140` directly writes bytes using a [`Writer`]. This
 /// makes `WriteStd140` usable for writing slices or other DSTs that could not
 /// implement `AsStd140` without allocating new memory on the heap.
+#[cfg(feature = "std")]
 pub trait WriteStd140 {
     /// Writes this value into the given [`Writer`] using `std140` layout rules.
     ///
@@ -118,6 +231,7 @@ pub trait WriteStd140 {
     }
 }
 
+#[cfg(feature = "std")]
 impl<T> WriteStd140 for T
 where
     T: AsStd140,
@@ -131,6 +245,7 @@ where
     }
 }
 
+#[cfg(feature = "std")]
 impl<T> WriteStd140 for [T]
 where
     T: WriteStd140,

crates/crevice/src/std430.rs

@@ -4,11 +4,13 @@
 mod primitives;
 mod sizer;
 mod traits;
+#[cfg(feature = "std")]
 mod writer;
 
 pub use self::primitives::*;
 pub use self::sizer::*;
 pub use self::traits::*;
+#[cfg(feature = "std")]
 pub use self::writer::*;
 
 pub use crevice_derive::AsStd430;

crates/crevice/src/std430/primitives.rs

@@ -1,21 +1,28 @@
 use bytemuck::{Pod, Zeroable};
 
-use crate::std430::Std430;
+use crate::std430::{Std430, Std430Padded};
+
+use crate::internal::align_offset;
+use core::mem::size_of;
 
 unsafe impl Std430 for f32 {
     const ALIGNMENT: usize = 4;
+    type Padded = Self;
 }
 
 unsafe impl Std430 for f64 {
     const ALIGNMENT: usize = 8;
+    type Padded = Self;
 }
 
 unsafe impl Std430 for i32 {
     const ALIGNMENT: usize = 4;
+    type Padded = Self;
 }
 
 unsafe impl Std430 for u32 {
     const ALIGNMENT: usize = 4;
+    type Padded = Self;
 }
 
 macro_rules! vectors {
@@ -37,6 +44,7 @@ macro_rules! vectors {
 
             unsafe impl Std430 for $name {
                 const ALIGNMENT: usize = $align;
+                type Padded = Std430Padded<Self, {align_offset(size_of::<$name>(), $align)}>;
             }
         )+
     };
@@ -87,6 +95,9 @@ macro_rules! matrices {
 
             unsafe impl Std430 for $name {
                 const ALIGNMENT: usize = $align;
+                /// Matrices are technically arrays of primitives, and as such require pad at end.
+                const PAD_AT_END: bool = true;
+                type Padded = Std430Padded<Self, {align_offset(size_of::<$name>(), $align)}>;
             }
         )+
     };

crates/crevice/src/std430/sizer.rs

@@ -1,4 +1,4 @@
-use std::mem::size_of;
+use core::mem::size_of;
 
 use crate::internal::align_offset;
 use crate::std430::{AsStd430, Std430};

crates/crevice/src/std430/traits.rs

@@ -1,8 +1,10 @@
+use core::mem::{size_of, MaybeUninit};
+#[cfg(feature = "std")]
 use std::io::{self, Write};
-use std::mem::size_of;
 
 use bytemuck::{bytes_of, Pod, Zeroable};
 
+#[cfg(feature = "std")]
 use crate::std430::Writer;
 
 /// Trait implemented for all `std430` primitives. Generally should not be
@@ -15,6 +17,15 @@ pub unsafe trait Std430: Copy + Zeroable + Pod {
     /// control and zero their padding bytes, making converting them to and from
     /// slices safe.
     const ALIGNMENT: usize;
+    /// Whether this type requires a padding at the end (ie, is a struct or an array
+    /// of primitives).
+    /// See https://www.khronos.org/registry/OpenGL/specs/gl/glspec45.core.pdf#page=159
+    /// (rule 4 and 9)
+    const PAD_AT_END: bool = false;
+    /// Padded type (Std430Padded specialization)
+    /// The usual implementation is
+    /// type Padded = Std430Padded<Self, {align_offset(size_of::<Self>(), ALIGNMENT)}>;
+    type Padded: Std430Convertible<Self>;
 
     /// Casts the type to a byte array. Implementors should not override this
     /// method.
@@ -27,6 +38,35 @@ pub unsafe trait Std430: Copy + Zeroable + Pod {
     }
 }
 
+/// Trait specifically for Std430::Padded, implements conversions between padded type and base type.
+pub trait Std430Convertible<T: Std430>: Copy {
+    /// Convert from self to Std430
+    fn into_std430(self) -> T;
+    /// Convert from Std430 to self
+    fn from_std430(_: T) -> Self;
+}
+
+impl<T: Std430> Std430Convertible<T> for T {
+    fn into_std430(self) -> T {
+        self
+    }
+    fn from_std430(also_self: T) -> Self {
+        also_self
+    }
+}
+
+/// Unfortunately, we cannot easily derive padded representation for generic Std140 types.
+/// For now, we'll just use this empty enum with no values.
+#[derive(Copy, Clone)]
+pub enum InvalidPadded {}
+impl<T: Std430> Std430Convertible<T> for InvalidPadded {
+    fn into_std430(self) -> T {
+        unimplemented!()
+    }
+    fn from_std430(_: T) -> Self {
+        unimplemented!()
+    }
+}
 /**
 Trait implemented for all types that can be turned into `std430` values.
 
@@ -80,6 +120,9 @@ pub trait AsStd430 {
     fn std430_size_static() -> usize {
         size_of::<Self::Std430Type>()
     }
+
+    /// Converts from `std430` version of self to self.
+    fn from_std430(value: Self::Std430Type) -> Self;
 }
 
 impl<T> AsStd430 for T
@@ -91,6 +134,75 @@ where
     fn as_std430(&self) -> Self {
         *self
     }
+
+    fn from_std430(value: Self) -> Self {
+        value
+    }
+}
+
+#[doc(hidden)]
+#[derive(Copy, Clone, Debug)]
+pub struct Std430Padded<T: Std430, const PAD: usize> {
+    inner: T,
+    _padding: [u8; PAD],
+}
+
+unsafe impl<T: Std430, const PAD: usize> Zeroable for Std430Padded<T, PAD> {}
+unsafe impl<T: Std430, const PAD: usize> Pod for Std430Padded<T, PAD> {}
+
+impl<T: Std430, const PAD: usize> Std430Convertible<T> for Std430Padded<T, PAD> {
+    fn into_std430(self) -> T {
+        self.inner
+    }
+
+    fn from_std430(inner: T) -> Self {
+        Self {
+            inner,
+            _padding: [0u8; PAD],
+        }
+    }
+}
+
+#[doc(hidden)]
+#[derive(Copy, Clone, Debug)]
+#[repr(transparent)]
+pub struct Std430Array<T: Std430, const N: usize>([T::Padded; N]);
+
+unsafe impl<T: Std430, const N: usize> Zeroable for Std430Array<T, N> where T::Padded: Zeroable {}
+unsafe impl<T: Std430, const N: usize> Pod for Std430Array<T, N> where T::Padded: Pod {}
+unsafe impl<T: Std430, const N: usize> Std430 for Std430Array<T, N>
+where
+    T::Padded: Pod,
+{
+    const ALIGNMENT: usize = T::ALIGNMENT;
+    type Padded = Self;
+}
+
+impl<T: AsStd430, const N: usize> AsStd430 for [T; N]
+where
+    <T::Std430Type as Std430>::Padded: Pod,
+{
+    type Std430Type = Std430Array<T::Std430Type, N>;
+    fn as_std430(&self) -> Self::Std430Type {
+        let mut res: [MaybeUninit<<T::Std430Type as Std430>::Padded>; N] =
+            unsafe { MaybeUninit::uninit().assume_init() };
+
+        for i in 0..N {
+            res[i] = MaybeUninit::new(Std430Convertible::from_std430(self[i].as_std430()));
+        }
+
+        unsafe { core::mem::transmute_copy(&res) }
+    }
+
+    fn from_std430(val: Self::Std430Type) -> Self {
+        let mut res: [MaybeUninit<T>; N] = unsafe { MaybeUninit::uninit().assume_init() };
+
+        for i in 0..N {
+            res[i] = MaybeUninit::new(AsStd430::from_std430(val.0[i].into_std430()));
+        }
+
+        unsafe { core::mem::transmute_copy(&res) }
+    }
 }
 
 /// Trait implemented for all types that can be written into a buffer as
@@ -101,6 +213,7 @@ where
 /// `Std430` trait, `WriteStd430` directly writes bytes using a [`Writer`]. This
 /// makes `WriteStd430` usable for writing slices or other DSTs that could not
 /// implement `AsStd430` without allocating new memory on the heap.
+#[cfg(feature = "std")]
 pub trait WriteStd430 {
     /// Writes this value into the given [`Writer`] using `std430` layout rules.
     ///
@@ -118,6 +231,7 @@ pub trait WriteStd430 {
     }
 }
 
+#[cfg(feature = "std")]
 impl<T> WriteStd430 for T
 where
     T: AsStd430,
@@ -131,6 +245,7 @@ where
     }
 }
 
+#[cfg(feature = "std")]
 impl<T> WriteStd430 for [T]
 where
     T: WriteStd430,

crates/crevice/tests/snapshots/std140__more_than_16_alignment.snap

@@ -1,16 +0,0 @@
----
-source: tests/std140.rs
-expression: "<<MoreThan16Alignment as AsStd140>::Std140Type as TypeLayout>::type_layout()"
----
-name: Std140MoreThan16Alignment
-size: 32
-alignment: 8
-fields:
-  - Field:
-      name: _doubles_align
-      ty: "[u8 ; Std140MoreThan16AlignmentAlignment :: _doubles_align()]"
-      size: 0
-  - Field:
-      name: doubles
-      ty: "< DVec4 as :: crevice :: std140 :: AsStd140 > :: Std140Type"
-      size: 32

crates/crevice/tests/snapshots/std140__point_light.snap

@@ -1,40 +0,0 @@
----
-source: tests/std140.rs
-expression: "<<PointLight as AsStd140>::Std140Type as TypeLayout>::type_layout()"
----
-name: Std140PointLight
-size: 48
-alignment: 4
-fields:
-  - Field:
-      name: _position_align
-      ty: "[u8 ; Std140PointLightAlignment :: _position_align()]"
-      size: 0
-  - Field:
-      name: position
-      ty: "< Vec3 as :: crevice :: std140 :: AsStd140 > :: Std140Type"
-      size: 12
-  - Field:
-      name: _diffuse_align
-      ty: "[u8 ; Std140PointLightAlignment :: _diffuse_align()]"
-      size: 4
-  - Field:
-      name: diffuse
-      ty: "< Vec3 as :: crevice :: std140 :: AsStd140 > :: Std140Type"
-      size: 12
-  - Field:
-      name: _specular_align
-      ty: "[u8 ; Std140PointLightAlignment :: _specular_align()]"
-      size: 4
-  - Field:
-      name: specular
-      ty: "< Vec3 as :: crevice :: std140 :: AsStd140 > :: Std140Type"
-      size: 12
-  - Field:
-      name: _brightness_align
-      ty: "[u8 ; Std140PointLightAlignment :: _brightness_align()]"
-      size: 0
-  - Field:
-      name: brightness
-      ty: "< f32 as :: crevice :: std140 :: AsStd140 > :: Std140Type"
-      size: 4

crates/crevice/tests/snapshots/std140__primitive_f32.snap

@@ -1,24 +0,0 @@
----
-source: tests/std140.rs
-expression: "<<PrimitiveF32 as AsStd140>::Std140Type as TypeLayout>::layout()"
----
-name: Std140PrimitiveF32
-size: 8
-alignment: 4
-fields:
-  - Field:
-      name: _x_align
-      ty: "[u8 ; Std140PrimitiveF32Alignment :: _x_align()]"
-      size: 0
-  - Field:
-      name: x
-      ty: "< f32 as :: crevice :: std140 :: AsStd140 > :: Std140Type"
-      size: 4
-  - Field:
-      name: _y_align
-      ty: "[u8 ; Std140PrimitiveF32Alignment :: _y_align()]"
-      size: 0
-  - Field:
-      name: y
-      ty: "< f32 as :: crevice :: std140 :: AsStd140 > :: Std140Type"
-      size: 4

crates/crevice/tests/snapshots/std140__using_vec3_padding.snap

@@ -1,24 +0,0 @@
----
-source: tests/std140.rs
-expression: "<<UsingVec3Padding as AsStd140>::Std140Type as TypeLayout>::layout()"
----
-name: Std140UsingVec3Padding
-size: 16
-alignment: 4
-fields:
-  - Field:
-      name: _pos_align
-      ty: "[u8 ; Std140UsingVec3PaddingAlignment :: _pos_align()]"
-      size: 0
-  - Field:
-      name: pos
-      ty: "< Vec3 as :: crevice :: std140 :: AsStd140 > :: Std140Type"
-      size: 12
-  - Field:
-      name: _brightness_align
-      ty: "[u8 ; Std140UsingVec3PaddingAlignment :: _brightness_align()]"
-      size: 0
-  - Field:
-      name: brightness
-      ty: "< f32 as :: crevice :: std140 :: AsStd140 > :: Std140Type"
-      size: 4

crates/crevice/tests/snapshots/std140__vec3.snap

@@ -1,24 +0,0 @@
----
-source: tests/std140.rs
-expression: "<<TestVec3 as AsStd140>::Std140Type as TypeLayout>::layout()"
----
-name: Std140TestVec3
-size: 28
-alignment: 4
-fields:
-  - Field:
-      name: _pos_align
-      ty: "[u8 ; Std140TestVec3Alignment :: _pos_align()]"
-      size: 0
-  - Field:
-      name: pos
-      ty: "< Vec3 as :: crevice :: std140 :: AsStd140 > :: Std140Type"
-      size: 12
-  - Field:
-      name: _velocity_align
-      ty: "[u8 ; Std140TestVec3Alignment :: _velocity_align()]"
-      size: 4
-  - Field:
-      name: velocity
-      ty: "< Vec3 as :: crevice :: std140 :: AsStd140 > :: Std140Type"
-      size: 12

crates/crevice/tests/std140.rs

@@ -1,121 +0,0 @@
-use insta::assert_yaml_snapshot;
-use type_layout::TypeLayout;
-
-use crevice::std140::{AsStd140, DVec4, Std140, Vec3};
-
-#[derive(AsStd140)]
-struct PrimitiveF32 {
-    x: f32,
-    y: f32,
-}
-
-#[test]
-fn primitive_f32() {
-    assert_yaml_snapshot!(<<PrimitiveF32 as AsStd140>::Std140Type as TypeLayout>::type_layout());
-
-    assert_eq!(<PrimitiveF32 as AsStd140>::Std140Type::ALIGNMENT, 16);
-
-    let value = PrimitiveF32 { x: 1.0, y: 2.0 };
-    let _value_std140 = value.as_std140();
-}
-
-#[derive(AsStd140)]
-struct TestVec3 {
-    pos: Vec3,
-    velocity: Vec3,
-}
-
-#[test]
-fn test_vec3() {
-    assert_yaml_snapshot!(<<TestVec3 as AsStd140>::Std140Type as TypeLayout>::type_layout());
-
-    assert_eq!(<TestVec3 as AsStd140>::Std140Type::ALIGNMENT, 16);
-
-    let value = TestVec3 {
-        pos: Vec3 {
-            x: 1.0,
-            y: 2.0,
-            z: 3.0,
-        },
-        velocity: Vec3 {
-            x: 4.0,
-            y: 5.0,
-            z: 6.0,
-        },
-    };
-    let _value_std140 = value.as_std140();
-}
-
-#[derive(AsStd140)]
-struct UsingVec3Padding {
-    pos: Vec3,
-    brightness: f32,
-}
-
-#[test]
-fn using_vec3_padding() {
-    assert_yaml_snapshot!(
-        <<UsingVec3Padding as AsStd140>::Std140Type as TypeLayout>::type_layout()
-    );
-
-    assert_eq!(<UsingVec3Padding as AsStd140>::Std140Type::ALIGNMENT, 16);
-
-    let value = UsingVec3Padding {
-        pos: Vec3 {
-            x: 1.0,
-            y: 2.0,
-            z: 3.0,
-        },
-        brightness: 4.0,
-    };
-    let _value_std140 = value.as_std140();
-}
-
-#[derive(AsStd140)]
-struct PointLight {
-    position: Vec3,
-    diffuse: Vec3,
-    specular: Vec3,
-    brightness: f32,
-}
-
-#[test]
-fn point_light() {
-    assert_yaml_snapshot!(<<PointLight as AsStd140>::Std140Type as TypeLayout>::type_layout());
-
-    assert_eq!(<PointLight as AsStd140>::Std140Type::ALIGNMENT, 16);
-
-    let value = PointLight {
-        position: Vec3 {
-            x: 1.0,
-            y: 2.0,
-            z: 3.0,
-        },
-        diffuse: Vec3 {
-            x: 1.0,
-            y: 2.0,
-            z: 3.0,
-        },
-        specular: Vec3 {
-            x: 1.0,
-            y: 2.0,
-            z: 3.0,
-        },
-        brightness: 4.0,
-    };
-    let _value_std140 = value.as_std140();
-}
-
-#[derive(AsStd140)]
-struct MoreThan16Alignment {
-    doubles: DVec4,
-}
-
-#[test]
-fn more_than_16_alignment() {
-    assert_yaml_snapshot!(
-        <<MoreThan16Alignment as AsStd140>::Std140Type as TypeLayout>::type_layout()
-    );
-
-    assert_eq!(<MoreThan16Alignment as AsStd140>::Std140Type::ALIGNMENT, 32);
-}

examples/3d/3d_scene_pipelined.rs

@@ -0,0 +1,95 @@
+use bevy::{
+    core::Time,
+    diagnostic::{FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
+    ecs::prelude::*,
+    input::Input,
+    math::Vec3,
+    pbr2::{PbrBundle, PointLightBundle, StandardMaterial},
+    prelude::{App, Assets, KeyCode, Transform},
+    render2::{
+        camera::PerspectiveCameraBundle,
+        color::Color,
+        mesh::{shape, Mesh},
+    },
+    wgpu2::diagnostic::WgpuResourceDiagnosticsPlugin,
+    PipelinedDefaultPlugins,
+};
+
+fn main() {
+    App::new()
+        .add_plugins(PipelinedDefaultPlugins)
+        .add_plugin(FrameTimeDiagnosticsPlugin::default())
+        .add_plugin(LogDiagnosticsPlugin::default())
+        .add_plugin(WgpuResourceDiagnosticsPlugin::default())
+        .add_startup_system(setup.system())
+        .add_system(movement.system())
+        .run();
+}
+
+struct Movable;
+
+/// set up a simple 3D scene
+fn setup(
+    mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+) {
+    // plane
+    commands.spawn_bundle(PbrBundle {
+        mesh: meshes.add(Mesh::from(shape::Plane { size: 5.0 })),
+        material: materials.add(Color::rgb(0.3, 0.5, 0.3).into()),
+        ..Default::default()
+    });
+    // cube
+    commands
+        .spawn_bundle(PbrBundle {
+            mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
+            material: materials.add(Color::rgb(0.8, 0.7, 0.6).into()),
+            transform: Transform::from_xyz(0.0, 1.0, 0.0),
+            ..Default::default()
+        })
+        .insert(Movable);
+    // sphere
+    commands
+        .spawn_bundle(PbrBundle {
+            mesh: meshes.add(Mesh::from(shape::UVSphere { radius: 0.5, ..Default::default() })),
+            material: materials.add(Color::rgb(0.8, 0.7, 0.6).into()),
+            transform: Transform::from_xyz(1.5, 1.0, 1.5),
+            ..Default::default()
+        })
+        .insert(Movable);
+    // light
+    commands.spawn_bundle(PointLightBundle {
+        transform: Transform::from_xyz(5.0, 8.0, 2.0),
+        ..Default::default()
+    });
+    // camera
+    commands.spawn_bundle(PerspectiveCameraBundle {
+        transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
+        ..Default::default()
+    });
+}
+
+fn movement(
+    input: Res<Input<KeyCode>>,
+    time: Res<Time>,
+    mut query: Query<&mut Transform, With<Movable>>,
+) {
+    for mut transform in query.iter_mut() {
+        let mut direction = Vec3::ZERO;
+        if input.pressed(KeyCode::Up) {
+            direction.y += 1.0;
+        }
+        if input.pressed(KeyCode::Down) {
+            direction.y -= 1.0;
+        }
+        if input.pressed(KeyCode::Left) {
+            direction.x -= 1.0;
+        }
+        if input.pressed(KeyCode::Right) {
+            direction.x += 1.0;
+        }
+
+        transform.translation += time.delta_seconds() * 2.0 * direction;
+    }
+}

examples/3d/render_to_texture.rs

@@ -224,7 +224,7 @@ fn setup(
 }
 
 fn main() {
-    let mut app = App::build();
+    let mut app = App::new();
     app.add_plugins(DefaultPlugins)
         .add_startup_system(setup.system())
         .add_system(cube_rotator_system.system())

examples/async_tasks/async_compute.rs

@@ -9,7 +9,7 @@ use std::time::{Duration, Instant};
 /// This example shows how to use the ECS and the AsyncComputeTaskPool
 /// to spawn, poll, and complete tasks across systems and system ticks.
 fn main() {
-    App::build()
+    App::new()
         .insert_resource(Msaa { samples: 4 })
         .add_plugins(DefaultPlugins)
         .add_startup_system(setup_env.system())

examples/ecs/iter_combinations.rs

@@ -7,7 +7,7 @@ struct FixedUpdateStage;
 const DELTA_TIME: f64 = 0.01;
 
 fn main() {
-    App::build()
+    App::new()
         .insert_resource(Msaa { samples: 4 })
         .add_plugins(DefaultPlugins)
         .add_startup_system(generate_bodies.system())

examples/ecs/query_bundle.rs

@@ -1,7 +1,7 @@
 use bevy::{log::LogPlugin, prelude::*};
 
 fn main() {
-    App::build()
+    App::new()
         .add_plugin(LogPlugin)
         .add_startup_system(setup.system())
         .add_system(log_names.system().label(LogNamesSystem))

examples/ecs/system_sets.rs

@@ -48,7 +48,7 @@ pub enum PhysicsSystem {
 /// Lastly a system with run criterion _done_ is used to exit the app.
 /// ```
 fn main() {
-    App::build()
+    App::new()
         .add_plugins(DefaultPlugins)
         .init_resource::<Done>()
         // Note that the system sets added in this example set their run criteria explicitly.

pipelined/bevy_pbr2/Cargo.toml

@@ -0,0 +1,30 @@
+[package]
+name = "bevy_pbr2"
+version = "0.5.0"
+edition = "2018"
+authors = [
+    "Bevy Contributors <bevyengine@gmail.com>",
+    "Carter Anderson <mcanders1@gmail.com>",
+]
+description = "Adds PBR rendering to Bevy Engine"
+homepage = "https://bevyengine.org"
+repository = "https://github.com/bevyengine/bevy"
+license = "MIT"
+keywords = ["bevy"]
+
+[dependencies]
+# bevy
+bevy_app = { path = "../../crates/bevy_app", version = "0.5.0" }
+bevy_asset = { path = "../../crates/bevy_asset", version = "0.5.0" }
+bevy_core = { path = "../../crates/bevy_core", version = "0.5.0" }
+bevy_ecs = { path = "../../crates/bevy_ecs", version = "0.5.0" }
+bevy_math = { path = "../../crates/bevy_math", version = "0.5.0" }
+bevy_reflect = { path = "../../crates/bevy_reflect", version = "0.5.0", features = ["bevy"] }
+bevy_render2 = { path = "../bevy_render2", version = "0.5.0" }
+bevy_transform = { path = "../../crates/bevy_transform", version = "0.5.0" }
+bevy_utils = { path = "../../crates/bevy_utils", version = "0.5.0" }
+
+# other
+# direct dependency required for derive macro
+bytemuck = { version = "1", features = ["derive"] }
+crevice = { path = "../../crates/crevice" }

pipelined/bevy_pbr2/src/bundle.rs

@@ -0,0 +1,32 @@
+use crate::{PointLight, StandardMaterial};
+use bevy_asset::Handle;
+use bevy_ecs::bundle::Bundle;
+use bevy_render2::mesh::Mesh;
+use bevy_transform::components::{GlobalTransform, Transform};
+
+#[derive(Bundle, Clone)]
+pub struct PbrBundle {
+    pub mesh: Handle<Mesh>,
+    pub material: Handle<StandardMaterial>,
+    pub transform: Transform,
+    pub global_transform: GlobalTransform,
+}
+
+impl Default for PbrBundle {
+    fn default() -> Self {
+        Self {
+            mesh: Default::default(),
+            material: Default::default(),
+            transform: Default::default(),
+            global_transform: Default::default(),
+        }
+    }
+}
+
+/// A component bundle for "light" entities
+#[derive(Debug, Bundle, Default)]
+pub struct PointLightBundle {
+    pub point_light: PointLight,
+    pub transform: Transform,
+    pub global_transform: GlobalTransform,
+}

pipelined/bevy_pbr2/src/lib.rs

@@ -0,0 +1,88 @@
+mod bundle;
+mod light;
+mod material;
+mod render;
+
+pub use bundle::*;
+pub use light::*;
+pub use material::*;
+pub use render::*;
+
+use bevy_app::prelude::*;
+use bevy_asset::AddAsset;
+use bevy_ecs::prelude::*;
+use bevy_render2::{
+    core_pipeline,
+    render_graph::RenderGraph,
+    render_phase::{sort_phase_system, DrawFunctions},
+    RenderStage,
+};
+
+pub mod draw_3d_graph {
+    pub mod node {
+        pub const SHADOW_PASS: &'static str = "shadow_pass";
+    }
+}
+
+#[derive(Default)]
+pub struct PbrPlugin;
+
+impl Plugin for PbrPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_asset::<StandardMaterial>();
+
+        let render_app = app.sub_app_mut(0);
+        render_app
+            .add_system_to_stage(RenderStage::Extract, render::extract_meshes.system())
+            .add_system_to_stage(RenderStage::Extract, render::extract_lights.system())
+            .add_system_to_stage(RenderStage::Prepare, render::prepare_meshes.system())
+            .add_system_to_stage(
+                RenderStage::Prepare,
+                // this is added as an exclusive system because it contributes new views. it must run (and have Commands applied)
+                // _before_ the `prepare_views()` system is run. ideally this becomes a normal system when "stageless" features come out
+                render::prepare_lights.exclusive_system(),
+            )
+            .add_system_to_stage(RenderStage::Queue, render::queue_meshes.system())
+            .add_system_to_stage(
+                RenderStage::PhaseSort,
+                sort_phase_system::<ShadowPhase>.system(),
+            )
+            .add_system_to_stage(RenderStage::Cleanup, render::cleanup_view_lights.system())
+            .init_resource::<PbrShaders>()
+            .init_resource::<ShadowShaders>()
+            .init_resource::<MeshMeta>()
+            .init_resource::<LightMeta>();
+
+        let draw_pbr = DrawPbr::new(&mut render_app.world);
+        let draw_shadow_mesh = DrawShadowMesh::new(&mut render_app.world);
+        let shadow_pass_node = ShadowPassNode::new(&mut render_app.world);
+        let render_world = render_app.world.cell();
+        let draw_functions = render_world.get_resource::<DrawFunctions>().unwrap();
+        draw_functions.write().add(draw_pbr);
+        draw_functions.write().add(draw_shadow_mesh);
+        let mut graph = render_world.get_resource_mut::<RenderGraph>().unwrap();
+        graph.add_node("pbr", PbrNode);
+        graph
+            .add_node_edge("pbr", core_pipeline::node::MAIN_PASS_DEPENDENCIES)
+            .unwrap();
+
+        let draw_3d_graph = graph
+            .get_sub_graph_mut(core_pipeline::draw_3d_graph::NAME)
+            .unwrap();
+        draw_3d_graph.add_node(draw_3d_graph::node::SHADOW_PASS, shadow_pass_node);
+        draw_3d_graph
+            .add_node_edge(
+                draw_3d_graph::node::SHADOW_PASS,
+                core_pipeline::draw_3d_graph::node::MAIN_PASS,
+            )
+            .unwrap();
+        draw_3d_graph
+            .add_slot_edge(
+                draw_3d_graph.input_node().unwrap().id,
+                core_pipeline::draw_3d_graph::input::VIEW_ENTITY,
+                draw_3d_graph::node::SHADOW_PASS,
+                ShadowPassNode::IN_VIEW,
+            )
+            .unwrap();
+    }
+}

pipelined/bevy_pbr2/src/light.rs

@@ -0,0 +1,24 @@
+use bevy_ecs::reflect::ReflectComponent;
+use bevy_reflect::Reflect;
+use bevy_render2::color::Color;
+
+/// A point light
+#[derive(Debug, Clone, Copy, Reflect)]
+#[reflect(Component)]
+pub struct PointLight {
+    pub color: Color,
+    pub intensity: f32,
+    pub range: f32,
+    pub radius: f32,
+}
+
+impl Default for PointLight {
+    fn default() -> Self {
+        PointLight {
+            color: Color::rgb(1.0, 1.0, 1.0),
+            intensity: 200.0,
+            range: 20.0,
+            radius: 0.0,
+        }
+    }
+}

pipelined/bevy_pbr2/src/material.rs

@@ -0,0 +1,17 @@
+use bevy_reflect::{Reflect, TypeUuid};
+use bevy_render2::color::Color;
+
+#[derive(Debug, Default, Clone, TypeUuid, Reflect)]
+#[uuid = "7494888b-c082-457b-aacf-517228cc0c22"]
+pub struct StandardMaterial {
+    pub color: Color,
+}
+
+impl From<Color> for StandardMaterial {
+    fn from(color: Color) -> Self {
+        StandardMaterial {
+            color,
+            ..Default::default()
+        }
+    }
+}

pipelined/bevy_pbr2/src/render/light.rs

@@ -0,0 +1,424 @@
+use crate::{render::MeshViewBindGroups, ExtractedMeshes, PointLight};
+use bevy_ecs::{prelude::*, system::SystemState};
+use bevy_math::{Mat4, Vec3, Vec4};
+use bevy_render2::{
+    color::Color,
+    core_pipeline::Transparent3dPhase,
+    pass::*,
+    pipeline::*,
+    render_graph::{Node, NodeRunError, RenderGraphContext, SlotInfo, SlotType},
+    render_phase::{Draw, DrawFunctions, RenderPhase, TrackedRenderPass},
+    render_resource::{DynamicUniformVec, SamplerId, TextureId, TextureViewId},
+    renderer::{RenderContext, RenderResources},
+    shader::{Shader, ShaderStage, ShaderStages},
+    texture::*,
+    view::{ExtractedView, ViewUniform},
+};
+use bevy_transform::components::GlobalTransform;
+use crevice::std140::AsStd140;
+use std::num::NonZeroU32;
+
+pub struct ExtractedPointLight {
+    color: Color,
+    intensity: f32,
+    range: f32,
+    radius: f32,
+    transform: GlobalTransform,
+}
+
+#[repr(C)]
+#[derive(Copy, Clone, AsStd140, Default, Debug)]
+pub struct GpuLight {
+    color: Vec4,
+    range: f32,
+    radius: f32,
+    position: Vec3,
+    view_proj: Mat4,
+}
+
+#[repr(C)]
+#[derive(Copy, Clone, Debug, AsStd140)]
+pub struct GpuLights {
+    len: u32,
+    lights: [GpuLight; MAX_POINT_LIGHTS],
+}
+
+// NOTE: this must be kept in sync MAX_POINT_LIGHTS in pbr.frag
+pub const MAX_POINT_LIGHTS: usize = 10;
+pub const SHADOW_SIZE: Extent3d = Extent3d {
+    width: 1024,
+    height: 1024,
+    depth_or_array_layers: MAX_POINT_LIGHTS as u32,
+};
+pub const SHADOW_FORMAT: TextureFormat = TextureFormat::Depth32Float;
+
+pub struct ShadowShaders {
+    pub pipeline: PipelineId,
+    pub pipeline_descriptor: RenderPipelineDescriptor,
+    pub light_sampler: SamplerId,
+}
+
+// TODO: this pattern for initializing the shaders / pipeline isn't ideal. this should be handled by the asset system
+impl FromWorld for ShadowShaders {
+    fn from_world(world: &mut World) -> Self {
+        let render_resources = world.get_resource::<RenderResources>().unwrap();
+        let vertex_shader = Shader::from_glsl(ShaderStage::Vertex, include_str!("pbr.vert"))
+            .get_spirv_shader(None)
+            .unwrap();
+        let vertex_layout = vertex_shader.reflect_layout(true).unwrap();
+
+        let mut pipeline_layout = PipelineLayout::from_shader_layouts(&mut [vertex_layout]);
+
+        let vertex = render_resources.create_shader_module(&vertex_shader);
+
+        pipeline_layout.vertex_buffer_descriptors = vec![VertexBufferLayout {
+            stride: 32,
+            name: "Vertex".into(),
+            step_mode: InputStepMode::Vertex,
+            attributes: vec![
+                // GOTCHA! Vertex_Position isn't first in the buffer due to how Mesh sorts attributes (alphabetically)
+                VertexAttribute {
+                    name: "Vertex_Position".into(),
+                    format: VertexFormat::Float32x3,
+                    offset: 12,
+                    shader_location: 0,
+                },
+                VertexAttribute {
+                    name: "Vertex_Normals".into(),
+                    format: VertexFormat::Float32x3,
+                    offset: 0,
+                    shader_location: 1,
+                },
+                VertexAttribute {
+                    name: "Vertex_Uv".into(),
+                    format: VertexFormat::Float32x2,
+                    offset: 24,
+                    shader_location: 2,
+                },
+            ],
+        }];
+
+        pipeline_layout.bind_group_mut(0).bindings[0].set_dynamic(true);
+        pipeline_layout.bind_group_mut(1).bindings[0].set_dynamic(true);
+        pipeline_layout.update_bind_group_ids();
+
+        let pipeline_descriptor = RenderPipelineDescriptor {
+            depth_stencil: Some(DepthStencilState {
+                format: SHADOW_FORMAT,
+                depth_write_enabled: true,
+                depth_compare: CompareFunction::LessEqual,
+                stencil: StencilState {
+                    front: StencilFaceState::IGNORE,
+                    back: StencilFaceState::IGNORE,
+                    read_mask: 0,
+                    write_mask: 0,
+                },
+                bias: DepthBiasState {
+                    constant: 2,
+                    slope_scale: 2.0,
+                    clamp: 0.0,
+                },
+            }),
+            primitive: PrimitiveState {
+                topology: PrimitiveTopology::TriangleList,
+                cull_mode: Some(Face::Back),
+                // TODO: detect if this feature is enabled
+                clamp_depth: false,
+                ..Default::default()
+            },
+            color_target_states: vec![],
+            ..RenderPipelineDescriptor::new(
+                ShaderStages {
+                    vertex,
+                    fragment: None,
+                },
+                pipeline_layout,
+            )
+        };
+
+        let pipeline = render_resources.create_render_pipeline(&pipeline_descriptor);
+
+        ShadowShaders {
+            pipeline,
+            pipeline_descriptor,
+            light_sampler: render_resources.create_sampler(&SamplerDescriptor {
+                address_mode_u: AddressMode::ClampToEdge,
+                address_mode_v: AddressMode::ClampToEdge,
+                address_mode_w: AddressMode::ClampToEdge,
+                mag_filter: FilterMode::Linear,
+                min_filter: FilterMode::Linear,
+                mipmap_filter: FilterMode::Nearest,
+                compare_function: Some(CompareFunction::LessEqual),
+                ..Default::default()
+            }),
+        }
+    }
+}
+
+// TODO: ultimately these could be filtered down to lights relevant to actual views
+pub fn extract_lights(
+    mut commands: Commands,
+    lights: Query<(Entity, &PointLight, &GlobalTransform)>,
+) {
+    for (entity, light, transform) in lights.iter() {
+        commands.get_or_spawn(entity).insert(ExtractedPointLight {
+            color: light.color,
+            intensity: light.intensity,
+            range: light.range,
+            radius: light.radius,
+            transform: transform.clone(),
+        });
+    }
+}
+
+pub struct ViewLight {
+    pub depth_texture: TextureViewId,
+}
+
+pub struct ViewLights {
+    pub light_depth_texture: TextureId,
+    pub light_depth_texture_view: TextureViewId,
+    pub lights: Vec<Entity>,
+    pub gpu_light_binding_index: u32,
+}
+
+#[derive(Default)]
+pub struct LightMeta {
+    pub view_gpu_lights: DynamicUniformVec<GpuLights>,
+}
+
+pub fn prepare_lights(
+    mut commands: Commands,
+    mut texture_cache: ResMut<TextureCache>,
+    render_resources: Res<RenderResources>,
+    mut light_meta: ResMut<LightMeta>,
+    views: Query<Entity, With<RenderPhase<Transparent3dPhase>>>,
+    lights: Query<&ExtractedPointLight>,
+) {
+    // PERF: view.iter().count() could be views.iter().len() if we implemented ExactSizeIterator for archetype-only filters
+    light_meta
+        .view_gpu_lights
+        .reserve_and_clear(views.iter().count(), &render_resources);
+
+    // set up light data for each view
+    for entity in views.iter() {
+        let light_depth_texture = texture_cache.get(
+            &render_resources,
+            TextureDescriptor {
+                size: SHADOW_SIZE,
+                mip_level_count: 1,
+                sample_count: 1,
+                dimension: TextureDimension::D2,
+                format: SHADOW_FORMAT,
+                usage: TextureUsage::RENDER_ATTACHMENT | TextureUsage::SAMPLED,
+                ..Default::default()
+            },
+        );
+        let mut view_lights = Vec::new();
+
+        let mut gpu_lights = GpuLights {
+            len: lights.iter().len() as u32,
+            lights: [GpuLight::default(); MAX_POINT_LIGHTS],
+        };
+
+        // TODO: this should select lights based on relevance to the view instead of the first ones that show up in a query
+        for (i, light) in lights.iter().enumerate().take(MAX_POINT_LIGHTS) {
+            let depth_texture_view = render_resources.create_texture_view(
+                light_depth_texture.texture,
+                TextureViewDescriptor {
+                    format: None,
+                    dimension: Some(TextureViewDimension::D2),
+                    aspect: TextureAspect::All,
+                    base_mip_level: 0,
+                    level_count: None,
+                    base_array_layer: i as u32,
+                    array_layer_count: NonZeroU32::new(1),
+                },
+            );
+
+            let view_transform = GlobalTransform::from_translation(light.transform.translation)
+                .looking_at(Vec3::default(), Vec3::Y);
+            // TODO: configure light projection based on light configuration
+            let projection = Mat4::perspective_rh(1.0472, 1.0, 1.0, 20.0);
+
+            gpu_lights.lights[i] = GpuLight {
+                // premultiply color by intensity
+                // we don't use the alpha at all, so no reason to multiply only [0..3]
+                color: (light.color * light.intensity).into(),
+                radius: light.radius.into(),
+                position: light.transform.translation.into(),
+                range: 1.0 / (light.range * light.range),
+                // this could technically be copied to the gpu from the light's ViewUniforms
+                view_proj: projection * view_transform.compute_matrix().inverse(),
+            };
+
+            let view_light_entity = commands
+                .spawn()
+                .insert_bundle((
+                    ViewLight {
+                        depth_texture: depth_texture_view,
+                    },
+                    ExtractedView {
+                        width: SHADOW_SIZE.width,
+                        height: SHADOW_SIZE.height,
+                        transform: view_transform.clone(),
+                        projection,
+                    },
+                    RenderPhase::<ShadowPhase>::default(),
+                ))
+                .id();
+            view_lights.push(view_light_entity);
+        }
+
+        commands.entity(entity).insert(ViewLights {
+            light_depth_texture: light_depth_texture.texture,
+            light_depth_texture_view: light_depth_texture.default_view,
+            lights: view_lights,
+            gpu_light_binding_index: light_meta.view_gpu_lights.push(gpu_lights),
+        });
+    }
+
+    light_meta
+        .view_gpu_lights
+        .write_to_staging_buffer(&render_resources);
+}
+
+// TODO: we can remove this once we move to RAII
+pub fn cleanup_view_lights(render_resources: Res<RenderResources>, query: Query<&ViewLight>) {
+    for view_light in query.iter() {
+        render_resources.remove_texture_view(view_light.depth_texture);
+    }
+}
+
+pub struct ShadowPhase;
+
+pub struct ShadowPassNode {
+    main_view_query: QueryState<&'static ViewLights>,
+    view_light_query: QueryState<(&'static ViewLight, &'static RenderPhase<ShadowPhase>)>,
+}
+
+impl ShadowPassNode {
+    pub const IN_VIEW: &'static str = "view";
+
+    pub fn new(world: &mut World) -> Self {
+        Self {
+            main_view_query: QueryState::new(world),
+            view_light_query: QueryState::new(world),
+        }
+    }
+}
+
+impl Node for ShadowPassNode {
+    fn input(&self) -> Vec<SlotInfo> {
+        vec![SlotInfo::new(ShadowPassNode::IN_VIEW, SlotType::Entity)]
+    }
+
+    fn update(&mut self, world: &mut World) {
+        self.main_view_query.update_archetypes(world);
+        self.view_light_query.update_archetypes(world);
+    }
+
+    fn run(
+        &self,
+        graph: &mut RenderGraphContext,
+        render_context: &mut dyn RenderContext,
+        world: &World,
+    ) -> Result<(), NodeRunError> {
+        let view_entity = graph.get_input_entity(Self::IN_VIEW)?;
+        let view_lights = self.main_view_query.get_manual(world, view_entity).unwrap();
+        for view_light_entity in view_lights.lights.iter().copied() {
+            let (view_light, shadow_phase) = self
+                .view_light_query
+                .get_manual(world, view_light_entity)
+                .unwrap();
+            let pass_descriptor = PassDescriptor {
+                color_attachments: Vec::new(),
+                depth_stencil_attachment: Some(RenderPassDepthStencilAttachment {
+                    attachment: TextureAttachment::Id(view_light.depth_texture),
+                    depth_ops: Some(Operations {
+                        load: LoadOp::Clear(1.0),
+                        store: true,
+                    }),
+                    stencil_ops: None,
+                }),
+                sample_count: 1,
+            };
+
+            let draw_functions = world.get_resource::<DrawFunctions>().unwrap();
+
+            render_context.begin_render_pass(
+                &pass_descriptor,
+                &mut |render_pass: &mut dyn RenderPass| {
+                    let mut draw_functions = draw_functions.write();
+                    let mut tracked_pass = TrackedRenderPass::new(render_pass);
+                    for drawable in shadow_phase.drawn_things.iter() {
+                        let draw_function = draw_functions.get_mut(drawable.draw_function).unwrap();
+                        draw_function.draw(
+                            world,
+                            &mut tracked_pass,
+                            view_light_entity,
+                            drawable.draw_key,
+                            drawable.sort_key,
+                        );
+                    }
+                },
+            );
+        }
+
+        Ok(())
+    }
+}
+
+type DrawShadowMeshParams<'a> = (
+    Res<'a, ShadowShaders>,
+    Res<'a, ExtractedMeshes>,
+    Query<'a, (&'a ViewUniform, &'a MeshViewBindGroups)>,
+);
+pub struct DrawShadowMesh {
+    params: SystemState<DrawShadowMeshParams<'static>>,
+}
+
+impl DrawShadowMesh {
+    pub fn new(world: &mut World) -> Self {
+        Self {
+            params: SystemState::new(world),
+        }
+    }
+}
+
+impl Draw for DrawShadowMesh {
+    fn draw(
+        &mut self,
+        world: &World,
+        pass: &mut TrackedRenderPass,
+        view: Entity,
+        draw_key: usize,
+        _sort_key: usize,
+    ) {
+        let (shadow_shaders, extracted_meshes, views) = self.params.get(world);
+        let (view_uniforms, mesh_view_bind_groups) = views.get(view).unwrap();
+        let layout = &shadow_shaders.pipeline_descriptor.layout;
+        let extracted_mesh = &extracted_meshes.meshes[draw_key];
+        pass.set_pipeline(shadow_shaders.pipeline);
+        pass.set_bind_group(
+            0,
+            layout.bind_group(0).id,
+            mesh_view_bind_groups.view_bind_group,
+            Some(&[view_uniforms.view_uniform_offset]),
+        );
+
+        pass.set_bind_group(
+            1,
+            layout.bind_group(1).id,
+            mesh_view_bind_groups.mesh_transform_bind_group,
+            Some(&[extracted_mesh.transform_binding_offset]),
+        );
+        pass.set_vertex_buffer(0, extracted_mesh.vertex_buffer, 0);
+        if let Some(index_info) = &extracted_mesh.index_info {
+            pass.set_index_buffer(index_info.buffer, 0, IndexFormat::Uint32);
+            pass.draw_indexed(0..index_info.count, 0, 0..1);
+        } else {
+            panic!("non-indexed drawing not supported yet")
+        }
+    }
+}

pipelined/bevy_pbr2/src/render/mod.rs

@@ -0,0 +1,367 @@
+mod light;
+pub use light::*;
+
+use crate::StandardMaterial;
+use bevy_asset::{Assets, Handle};
+use bevy_ecs::{prelude::*, system::SystemState};
+use bevy_math::Mat4;
+use bevy_render2::{
+    core_pipeline::Transparent3dPhase,
+    mesh::Mesh,
+    pipeline::*,
+    render_graph::{Node, NodeRunError, RenderGraphContext},
+    render_phase::{Draw, DrawFunctions, Drawable, RenderPhase, TrackedRenderPass},
+    render_resource::{BindGroupBuilder, BindGroupId, BufferId, DynamicUniformVec},
+    renderer::{RenderContext, RenderResources},
+    shader::{Shader, ShaderStage, ShaderStages},
+    texture::{TextureFormat, TextureSampleType},
+    view::{ViewMeta, ViewUniform},
+};
+use bevy_transform::components::GlobalTransform;
+
+pub struct PbrShaders {
+    pipeline: PipelineId,
+    pipeline_descriptor: RenderPipelineDescriptor,
+}
+
+// TODO: this pattern for initializing the shaders / pipeline isn't ideal. this should be handled by the asset system
+impl FromWorld for PbrShaders {
+    fn from_world(world: &mut World) -> Self {
+        let render_resources = world.get_resource::<RenderResources>().unwrap();
+        let vertex_shader = Shader::from_glsl(ShaderStage::Vertex, include_str!("pbr.vert"))
+            .get_spirv_shader(None)
+            .unwrap();
+        let fragment_shader = Shader::from_glsl(ShaderStage::Fragment, include_str!("pbr.frag"))
+            .get_spirv_shader(None)
+            .unwrap();
+
+        let vertex_layout = vertex_shader.reflect_layout(true).unwrap();
+        let fragment_layout = fragment_shader.reflect_layout(true).unwrap();
+
+        let mut pipeline_layout =
+            PipelineLayout::from_shader_layouts(&mut [vertex_layout, fragment_layout]);
+
+        let vertex = render_resources.create_shader_module(&vertex_shader);
+        let fragment = render_resources.create_shader_module(&fragment_shader);
+
+        pipeline_layout.vertex_buffer_descriptors = vec![VertexBufferLayout {
+            stride: 32,
+            name: "Vertex".into(),
+            step_mode: InputStepMode::Vertex,
+            attributes: vec![
+                // GOTCHA! Vertex_Position isn't first in the buffer due to how Mesh sorts attributes (alphabetically)
+                VertexAttribute {
+                    name: "Vertex_Position".into(),
+                    format: VertexFormat::Float32x3,
+                    offset: 12,
+                    shader_location: 0,
+                },
+                VertexAttribute {
+                    name: "Vertex_Normals".into(),
+                    format: VertexFormat::Float32x3,
+                    offset: 0,
+                    shader_location: 1,
+                },
+                VertexAttribute {
+                    name: "Vertex_Uv".into(),
+                    format: VertexFormat::Float32x2,
+                    offset: 24,
+                    shader_location: 2,
+                },
+            ],
+        }];
+
+        pipeline_layout.bind_group_mut(0).bindings[0].set_dynamic(true);
+        pipeline_layout.bind_group_mut(0).bindings[1].set_dynamic(true);
+        if let BindType::Texture { sample_type, .. } =
+            &mut pipeline_layout.bind_group_mut(0).bindings[2].bind_type
+        {
+            *sample_type = TextureSampleType::Depth;
+        }
+        if let BindType::Sampler { comparison, .. } =
+            &mut pipeline_layout.bind_group_mut(0).bindings[3].bind_type
+        {
+            *comparison = true;
+        }
+        pipeline_layout.bind_group_mut(1).bindings[0].set_dynamic(true);
+
+        pipeline_layout.update_bind_group_ids();
+
+        let pipeline_descriptor = RenderPipelineDescriptor {
+            depth_stencil: Some(DepthStencilState {
+                format: TextureFormat::Depth32Float,
+                depth_write_enabled: true,
+                depth_compare: CompareFunction::Less,
+                stencil: StencilState {
+                    front: StencilFaceState::IGNORE,
+                    back: StencilFaceState::IGNORE,
+                    read_mask: 0,
+                    write_mask: 0,
+                },
+                bias: DepthBiasState {
+                    constant: 0,
+                    slope_scale: 0.0,
+                    clamp: 0.0,
+                },
+            }),
+            color_target_states: vec![ColorTargetState {
+                format: TextureFormat::default(),
+                blend: Some(BlendState {
+                    color: BlendComponent {
+                        src_factor: BlendFactor::SrcAlpha,
+                        dst_factor: BlendFactor::OneMinusSrcAlpha,
+                        operation: BlendOperation::Add,
+                    },
+                    alpha: BlendComponent {
+                        src_factor: BlendFactor::One,
+                        dst_factor: BlendFactor::One,
+                        operation: BlendOperation::Add,
+                    },
+                }),
+                write_mask: ColorWrite::ALL,
+            }],
+            ..RenderPipelineDescriptor::new(
+                ShaderStages {
+                    vertex,
+                    fragment: Some(fragment),
+                },
+                pipeline_layout,
+            )
+        };
+
+        let pipeline = render_resources.create_render_pipeline(&pipeline_descriptor);
+
+        PbrShaders {
+            pipeline,
+            pipeline_descriptor,
+        }
+    }
+}
+
+struct ExtractedMesh {
+    transform: Mat4,
+    vertex_buffer: BufferId,
+    index_info: Option<IndexInfo>,
+    transform_binding_offset: u32,
+}
+
+struct IndexInfo {
+    buffer: BufferId,
+    count: u32,
+}
+
+pub struct ExtractedMeshes {
+    meshes: Vec<ExtractedMesh>,
+}
+
+pub fn extract_meshes(
+    mut commands: Commands,
+    meshes: Res<Assets<Mesh>>,
+    _materials: Res<Assets<StandardMaterial>>,
+    query: Query<(&GlobalTransform, &Handle<Mesh>, &Handle<StandardMaterial>)>,
+) {
+    let mut extracted_meshes = Vec::new();
+    for (transform, mesh_handle, _material_handle) in query.iter() {
+        if let Some(mesh) = meshes.get(mesh_handle) {
+            if let Some(gpu_data) = &mesh.gpu_data() {
+                extracted_meshes.push(ExtractedMesh {
+                    transform: transform.compute_matrix(),
+                    vertex_buffer: gpu_data.vertex_buffer,
+                    index_info: gpu_data.index_buffer.map(|i| IndexInfo {
+                        buffer: i,
+                        count: mesh.indices().unwrap().len() as u32,
+                    }),
+                    transform_binding_offset: 0,
+                })
+            }
+        }
+    }
+
+    commands.insert_resource(ExtractedMeshes {
+        meshes: extracted_meshes,
+    });
+}
+
+#[derive(Default)]
+pub struct MeshMeta {
+    transform_uniforms: DynamicUniformVec<Mat4>,
+}
+
+pub fn prepare_meshes(
+    render_resources: Res<RenderResources>,
+    mut mesh_meta: ResMut<MeshMeta>,
+    mut extracted_meshes: ResMut<ExtractedMeshes>,
+) {
+    mesh_meta
+        .transform_uniforms
+        .reserve_and_clear(extracted_meshes.meshes.len(), &render_resources);
+    for extracted_mesh in extracted_meshes.meshes.iter_mut() {
+        extracted_mesh.transform_binding_offset =
+            mesh_meta.transform_uniforms.push(extracted_mesh.transform);
+    }
+
+    mesh_meta
+        .transform_uniforms
+        .write_to_staging_buffer(&render_resources);
+}
+
+// TODO: This is temporary. Once we expose BindGroupLayouts directly, we can create view bind groups without specific shader context
+struct MeshViewBindGroups {
+    view_bind_group: BindGroupId,
+    mesh_transform_bind_group: BindGroupId,
+}
+
+pub fn queue_meshes(
+    mut commands: Commands,
+    draw_functions: Res<DrawFunctions>,
+    render_resources: Res<RenderResources>,
+    pbr_shaders: Res<PbrShaders>,
+    shadow_shaders: Res<ShadowShaders>,
+    mesh_meta: Res<MeshMeta>,
+    light_meta: Res<LightMeta>,
+    view_meta: Res<ViewMeta>,
+    extracted_meshes: Res<ExtractedMeshes>,
+    mut views: Query<(Entity, &ViewLights, &mut RenderPhase<Transparent3dPhase>)>,
+    mut view_light_shadow_phases: Query<&mut RenderPhase<ShadowPhase>>,
+) {
+    if extracted_meshes.meshes.is_empty() {
+        return;
+    }
+    for (entity, view_lights, mut transparent_phase) in views.iter_mut() {
+        let layout = &pbr_shaders.pipeline_descriptor.layout;
+        let view_bind_group = BindGroupBuilder::default()
+            .add_binding(0, view_meta.uniforms.binding())
+            .add_binding(1, light_meta.view_gpu_lights.binding())
+            .add_binding(2, view_lights.light_depth_texture_view)
+            .add_binding(3, shadow_shaders.light_sampler)
+            .finish();
+
+        // TODO: this will only create the bind group if it isn't already created. this is a bit nasty
+        render_resources.create_bind_group(layout.bind_group(0).id, &view_bind_group);
+
+        let mesh_transform_bind_group = BindGroupBuilder::default()
+            .add_binding(0, mesh_meta.transform_uniforms.binding())
+            .finish();
+        render_resources.create_bind_group(layout.bind_group(1).id, &mesh_transform_bind_group);
+
+        commands.entity(entity).insert(MeshViewBindGroups {
+            view_bind_group: view_bind_group.id,
+            mesh_transform_bind_group: mesh_transform_bind_group.id,
+        });
+
+        let draw_pbr = draw_functions.read().get_id::<DrawPbr>().unwrap();
+        for i in 0..extracted_meshes.meshes.len() {
+            // TODO: currently there is only "transparent phase". this should pick transparent vs opaque according to the mesh material
+            transparent_phase.add(Drawable {
+                draw_function: draw_pbr,
+                draw_key: i,
+                sort_key: 0, // TODO: sort back-to-front
+            });
+        }
+
+        // ultimately lights should check meshes for relevancy (ex: light views can "see" different meshes than the main view can)
+        let draw_shadow_mesh = draw_functions.read().get_id::<DrawShadowMesh>().unwrap();
+        for view_light_entity in view_lights.lights.iter().copied() {
+            let mut shadow_phase = view_light_shadow_phases.get_mut(view_light_entity).unwrap();
+            let layout = &shadow_shaders.pipeline_descriptor.layout;
+            let shadow_view_bind_group = BindGroupBuilder::default()
+                .add_binding(0, view_meta.uniforms.binding())
+                .finish();
+
+            render_resources.create_bind_group(layout.bind_group(0).id, &shadow_view_bind_group);
+            // TODO: this should only queue up meshes that are actually visible by each "light view"
+            for i in 0..extracted_meshes.meshes.len() {
+                shadow_phase.add(Drawable {
+                    draw_function: draw_shadow_mesh,
+                    draw_key: i,
+                    sort_key: 0, // TODO: sort back-to-front
+                })
+            }
+
+            commands
+                .entity(view_light_entity)
+                .insert(MeshViewBindGroups {
+                    view_bind_group: shadow_view_bind_group.id,
+                    mesh_transform_bind_group: mesh_transform_bind_group.id,
+                });
+        }
+    }
+}
+
+// TODO: this logic can be moved to prepare_meshes once wgpu::Queue is exposed directly
+pub struct PbrNode;
+
+impl Node for PbrNode {
+    fn run(
+        &self,
+        _graph: &mut RenderGraphContext,
+        render_context: &mut dyn RenderContext,
+        world: &World,
+    ) -> Result<(), NodeRunError> {
+        let mesh_meta = world.get_resource::<MeshMeta>().unwrap();
+        let light_meta = world.get_resource::<LightMeta>().unwrap();
+        mesh_meta
+            .transform_uniforms
+            .write_to_uniform_buffer(render_context);
+        light_meta
+            .view_gpu_lights
+            .write_to_uniform_buffer(render_context);
+        Ok(())
+    }
+}
+
+type DrawPbrParams<'a> = (
+    Res<'a, PbrShaders>,
+    Res<'a, ExtractedMeshes>,
+    Query<'a, (&'a ViewUniform, &'a MeshViewBindGroups, &'a ViewLights)>,
+);
+pub struct DrawPbr {
+    params: SystemState<DrawPbrParams<'static>>,
+}
+
+impl DrawPbr {
+    pub fn new(world: &mut World) -> Self {
+        Self {
+            params: SystemState::new(world),
+        }
+    }
+}
+
+impl Draw for DrawPbr {
+    fn draw(
+        &mut self,
+        world: &World,
+        pass: &mut TrackedRenderPass,
+        view: Entity,
+        draw_key: usize,
+        _sort_key: usize,
+    ) {
+        let (pbr_shaders, extracted_meshes, views) = self.params.get(world);
+        let (view_uniforms, mesh_view_bind_groups, view_lights) = views.get(view).unwrap();
+        let layout = &pbr_shaders.pipeline_descriptor.layout;
+        let extracted_mesh = &extracted_meshes.meshes[draw_key];
+        pass.set_pipeline(pbr_shaders.pipeline);
+        pass.set_bind_group(
+            0,
+            layout.bind_group(0).id,
+            mesh_view_bind_groups.view_bind_group,
+            Some(&[
+                view_uniforms.view_uniform_offset,
+                view_lights.gpu_light_binding_index,
+            ]),
+        );
+        pass.set_bind_group(
+            1,
+            layout.bind_group(1).id,
+            mesh_view_bind_groups.mesh_transform_bind_group,
+            Some(&[extracted_mesh.transform_binding_offset]),
+        );
+        pass.set_vertex_buffer(0, extracted_mesh.vertex_buffer, 0);
+        if let Some(index_info) = &extracted_mesh.index_info {
+            pass.set_index_buffer(index_info.buffer, 0, IndexFormat::Uint32);
+            pass.draw_indexed(0..index_info.count, 0, 0..1);
+        } else {
+            panic!("non-indexed drawing not supported yet")
+        }
+    }
+}

pipelined/bevy_pbr2/src/render/pbr.frag

@@ -0,0 +1,298 @@
+#version 450
+
+layout(location = 0) in vec4 v_WorldPosition;
+layout(location = 1) in vec3 v_WorldNormal;
+layout(location = 2) in vec2 v_Uv;
+
+layout(location = 0) out vec4 o_Target;
+
+struct PointLight {
+    vec4 color;
+    float range;
+    float radius;
+    vec3 position;
+    mat4 projection;
+};
+
+// NOTE: this must be kept in sync with lights::MAX_LIGHTS
+// TODO: this can be removed if we move to storage buffers for light arrays
+const int MAX_POINT_LIGHTS = 10;
+
+layout(set = 0, binding = 0) uniform View {
+    mat4 ViewProj;
+    vec3 ViewWorldPosition;
+};
+layout(std140, set = 0, binding = 1) uniform Lights {
+    uint NumLights;
+    PointLight PointLights[MAX_POINT_LIGHTS];
+};
+layout(set = 0, binding = 2) uniform texture2DArray t_Shadow;
+layout(set = 0, binding = 3) uniform samplerShadow s_Shadow;
+
+#    define saturate(x) clamp(x, 0.0, 1.0)
+const float PI = 3.141592653589793;
+
+float pow5(float x) {
+    float x2 = x * x;
+    return x2 * x2 * x;
+}
+
+// distanceAttenuation is simply the square falloff of light intensity
+// combined with a smooth attenuation at the edge of the light radius
+//
+// light radius is a non-physical construct for efficiency purposes,
+// because otherwise every light affects every fragment in the scene
+float getDistanceAttenuation(float distanceSquare, float inverseRangeSquared) {
+    float factor = distanceSquare * inverseRangeSquared;
+    float smoothFactor = saturate(1.0 - factor * factor);
+    float attenuation = smoothFactor * smoothFactor;
+    return attenuation * 1.0 / max(distanceSquare, 1e-4);
+}
+
+// Normal distribution function (specular D)
+// Based on https://google.github.io/filament/Filament.html#citation-walter07
+
+// D_GGX(h,α) = α^2 / { π ((n⋅h)^2 (α2−1) + 1)^2 }
+
+// Simple implementation, has precision problems when using fp16 instead of fp32
+// see https://google.github.io/filament/Filament.html#listing_speculardfp16
+float D_GGX(float roughness, float NoH, const vec3 h) {
+    float oneMinusNoHSquared = 1.0 - NoH * NoH;
+    float a = NoH * roughness;
+    float k = roughness / (oneMinusNoHSquared + a * a);
+    float d = k * k * (1.0 / PI);
+    return d;
+}
+
+// Visibility function (Specular G)
+// V(v,l,a) = G(v,l,α) / { 4 (n⋅v) (n⋅l) }
+// such that f_r becomes
+// f_r(v,l) = D(h,α) V(v,l,α) F(v,h,f0)
+// where
+// V(v,l,α) = 0.5 / { n⋅l sqrt((n⋅v)^2 (1−α2) + α2) + n⋅v sqrt((n⋅l)^2 (1−α2) + α2) }
+// Note the two sqrt's, that may be slow on mobile, see https://google.github.io/filament/Filament.html#listing_approximatedspecularv
+float V_SmithGGXCorrelated(float roughness, float NoV, float NoL) {
+    float a2 = roughness * roughness;
+    float lambdaV = NoL * sqrt((NoV - a2 * NoV) * NoV + a2);
+    float lambdaL = NoV * sqrt((NoL - a2 * NoL) * NoL + a2);
+    float v = 0.5 / (lambdaV + lambdaL);
+    return v;
+}
+
+// Fresnel function
+// see https://google.github.io/filament/Filament.html#citation-schlick94
+// F_Schlick(v,h,f_0,f_90) = f_0 + (f_90 − f_0) (1 − v⋅h)^5
+vec3 F_Schlick(const vec3 f0, float f90, float VoH) {
+    // not using mix to keep the vec3 and float versions identical
+    return f0 + (f90 - f0) * pow5(1.0 - VoH);
+}
+
+float F_Schlick(float f0, float f90, float VoH) {
+    // not using mix to keep the vec3 and float versions identical
+    return f0 + (f90 - f0) * pow5(1.0 - VoH);
+}
+
+vec3 fresnel(vec3 f0, float LoH) {
+    // f_90 suitable for ambient occlusion
+    // see https://google.github.io/filament/Filament.html#lighting/occlusion
+    float f90 = saturate(dot(f0, vec3(50.0 * 0.33)));
+    return F_Schlick(f0, f90, LoH);
+}
+
+// Specular BRDF
+// https://google.github.io/filament/Filament.html#materialsystem/specularbrdf
+
+// Cook-Torrance approximation of the microfacet model integration using Fresnel law F to model f_m
+// f_r(v,l) = { D(h,α) G(v,l,α) F(v,h,f0) } / { 4 (n⋅v) (n⋅l) }
+vec3 specular(vec3 f0, float roughness, const vec3 h, float NoV, float NoL,
+              float NoH, float LoH, float specularIntensity) {
+    float D = D_GGX(roughness, NoH, h);
+    float V = V_SmithGGXCorrelated(roughness, NoV, NoL);
+    vec3 F = fresnel(f0, LoH);
+
+    return (specularIntensity * D * V) * F;
+}
+
+// Diffuse BRDF
+// https://google.github.io/filament/Filament.html#materialsystem/diffusebrdf
+// fd(v,l) = σ/π * 1 / { |n⋅v||n⋅l| } ∫Ω D(m,α) G(v,l,m) (v⋅m) (l⋅m) dm
+
+// simplest approximation
+// float Fd_Lambert() {
+//     return 1.0 / PI;
+// }
+//
+// vec3 Fd = diffuseColor * Fd_Lambert();
+
+// Disney approximation
+// See https://google.github.io/filament/Filament.html#citation-burley12
+// minimal quality difference
+float Fd_Burley(float roughness, float NoV, float NoL, float LoH) {
+    float f90 = 0.5 + 2.0 * roughness * LoH * LoH;
+    float lightScatter = F_Schlick(1.0, f90, NoL);
+    float viewScatter = F_Schlick(1.0, f90, NoV);
+    return lightScatter * viewScatter * (1.0 / PI);
+}
+
+// From https://www.unrealengine.com/en-US/blog/physically-based-shading-on-mobile
+vec3 EnvBRDFApprox(vec3 f0, float perceptual_roughness, float NoV) {
+    const vec4 c0 = { -1, -0.0275, -0.572, 0.022 };
+    const vec4 c1 = { 1, 0.0425, 1.04, -0.04 };
+    vec4 r = perceptual_roughness * c0 + c1;
+    float a004 = min(r.x * r.x, exp2(-9.28 * NoV)) * r.x + r.y;
+    vec2 AB = vec2(-1.04, 1.04) * a004 + r.zw;
+    return f0 * AB.x + AB.y;
+}
+
+float perceptualRoughnessToRoughness(float perceptualRoughness) {
+    // clamp perceptual roughness to prevent precision problems
+    // According to Filament design 0.089 is recommended for mobile
+    // Filament uses 0.045 for non-mobile
+    float clampedPerceptualRoughness = clamp(perceptualRoughness, 0.089, 1.0);
+    return clampedPerceptualRoughness * clampedPerceptualRoughness;
+}
+
+// from https://64.github.io/tonemapping/
+// reinhard on RGB oversaturates colors
+vec3 reinhard(vec3 color) {
+    return color / (1.0 + color);
+}
+
+vec3 reinhard_extended(vec3 color, float max_white) {
+    vec3 numerator = color * (1.0f + (color / vec3(max_white * max_white)));
+    return numerator / (1.0 + color);
+}
+
+// luminance coefficients from Rec. 709.
+// https://en.wikipedia.org/wiki/Rec._709
+float luminance(vec3 v) {
+    return dot(v, vec3(0.2126, 0.7152, 0.0722));
+}
+
+vec3 change_luminance(vec3 c_in, float l_out) {
+    float l_in = luminance(c_in);
+    return c_in * (l_out / l_in);
+}
+
+vec3 reinhard_luminance(vec3 color) {
+    float l_old = luminance(color);
+    float l_new = l_old / (1.0f + l_old);
+    return change_luminance(color, l_new);
+}
+
+vec3 reinhard_extended_luminance(vec3 color, float max_white_l) {
+    float l_old = luminance(color);
+    float numerator = l_old * (1.0f + (l_old / (max_white_l * max_white_l)));
+    float l_new = numerator / (1.0f + l_old);
+    return change_luminance(color, l_new);
+}
+
+vec3 point_light(PointLight light, float roughness, float NdotV, vec3 N, vec3 V, vec3 R, vec3 F0, vec3 diffuseColor) {
+    vec3 light_to_frag = light.position.xyz - v_WorldPosition.xyz;
+    float distance_square = dot(light_to_frag, light_to_frag);
+    float rangeAttenuation =
+        getDistanceAttenuation(distance_square, light.range);
+
+    // Specular.
+    // Representative Point Area Lights.
+    // see http://blog.selfshadow.com/publications/s2013-shading-course/karis/s2013_pbs_epic_notes_v2.pdf p14-16
+    float a = roughness;
+    vec3 centerToRay = dot(light_to_frag, R) * R - light_to_frag;
+    vec3 closestPoint = light_to_frag + centerToRay * saturate(light.radius * inversesqrt(dot(centerToRay, centerToRay)));
+    float LspecLengthInverse = inversesqrt(dot(closestPoint, closestPoint));
+    float normalizationFactor = a / saturate(a + (light.radius * 0.5 * LspecLengthInverse));
+    float specularIntensity = normalizationFactor * normalizationFactor;
+
+    vec3 L = closestPoint * LspecLengthInverse; // normalize() equivalent?
+    vec3 H = normalize(L + V);
+    float NoL = saturate(dot(N, L));
+    float NoH = saturate(dot(N, H));
+    float LoH = saturate(dot(L, H));
+
+    vec3 specular = specular(F0, roughness, H, NdotV, NoL, NoH, LoH, specularIntensity);
+
+    // Diffuse.
+    // Comes after specular since its NoL is used in the lighting equation.
+    L = normalize(light_to_frag);
+    H = normalize(L + V);
+    NoL = saturate(dot(N, L));
+    NoH = saturate(dot(N, H));
+    LoH = saturate(dot(L, H));
+
+    vec3 diffuse = diffuseColor * Fd_Burley(roughness, NdotV, NoL, LoH);
+
+    // Lout = f(v,l) Φ / { 4 π d^2 }⟨n⋅l⟩
+    // where
+    // f(v,l) = (f_d(v,l) + f_r(v,l)) * light_color
+    // Φ is light intensity
+
+    // our rangeAttentuation = 1 / d^2 multiplied with an attenuation factor for smoothing at the edge of the non-physical maximum light radius
+    // It's not 100% clear where the 1/4π goes in the derivation, but we follow the filament shader and leave it out
+
+    // See https://google.github.io/filament/Filament.html#mjx-eqn-pointLightLuminanceEquation
+    // TODO compensate for energy loss https://google.github.io/filament/Filament.html#materialsystem/improvingthebrdfs/energylossinspecularreflectance
+    // light.color.rgb is premultiplied with light.intensity on the CPU
+    return ((diffuse + specular) * light.color.rgb) * (rangeAttenuation * NoL);
+}
+
+float fetch_shadow(int light_id, vec4 homogeneous_coords) {
+    if (homogeneous_coords.w <= 0.0) {
+        return 1.0;
+    }
+    // compensate for the Y-flip difference between the NDC and texture coordinates
+    const vec2 flip_correction = vec2(0.5, -0.5);
+    // compute texture coordinates for shadow lookup
+    vec4 light_local = vec4(
+        homogeneous_coords.xy * flip_correction/homogeneous_coords.w + 0.5,
+        light_id,
+        homogeneous_coords.z / homogeneous_coords.w
+    );
+    // do the lookup, using HW PCF and comparison
+    return texture(sampler2DArrayShadow(t_Shadow, s_Shadow), light_local);
+}
+
+void main() {
+    vec4 color = vec4(0.6, 0.6, 0.6, 1.0); 
+    float metallic = 0.01;
+    float reflectance = 0.5;
+    float perceptual_roughness = 0.089;
+    vec3 emissive = vec3(0.0, 0.0, 0.0);
+    vec3 ambient_color = vec3(0.1, 0.1, 0.1);
+    float occlusion = 1.0;
+
+    float roughness = perceptualRoughnessToRoughness(perceptual_roughness);    
+    vec3 N = normalize(v_WorldNormal);
+    vec3 V = normalize(ViewWorldPosition.xyz - v_WorldPosition.xyz);
+    vec3 R = reflect(-V, N);
+    // Neubelt and Pettineo 2013, "Crafting a Next-gen Material Pipeline for The Order: 1886"
+    float NdotV = max(dot(N, V), 1e-4);
+
+    // Remapping [0,1] reflectance to F0
+    // See https://google.github.io/filament/Filament.html#materialsystem/parameterization/remapping
+    vec3 F0 = 0.16 * reflectance * reflectance * (1.0 - metallic) + color.rgb * metallic;
+
+    // Diffuse strength inversely related to metallicity
+    vec3 diffuse_color = color.rgb * (1.0 - metallic);
+
+    vec3 output_color = vec3(0.0);
+    for (int i = 0; i < int(NumLights); ++i) {
+        PointLight light = PointLights[i];
+        vec3 light_contrib = point_light(light, roughness, NdotV, N, V, R, F0, diffuse_color);
+        float shadow = fetch_shadow(i, light.projection * v_WorldPosition);
+        output_color += light_contrib * shadow;
+    }
+
+    vec3 diffuse_ambient = EnvBRDFApprox(diffuse_color, 1.0, NdotV);
+    vec3 specular_ambient = EnvBRDFApprox(F0, perceptual_roughness, NdotV);
+
+    output_color += (diffuse_ambient + specular_ambient) * ambient_color * occlusion;
+    output_color += emissive * color.a;
+
+    // tone_mapping
+    output_color = reinhard_luminance(output_color);
+    // Gamma correction.
+    // Not needed with sRGB buffer
+    // output_color = pow(output_color, vec3(1.0 / 2.2));
+
+    o_Target = vec4(output_color, 1.0);
+}

pipelined/bevy_pbr2/src/render/pbr.vert

@@ -0,0 +1,25 @@
+#version 450
+
+layout(location = 0) in vec3 Vertex_Position;
+layout(location = 1) in vec3 Vertex_Normal;
+layout(location = 2) in vec2 Vertex_Uv;
+
+layout(location = 0) out vec4 v_WorldPosition;
+layout(location = 1) out vec3 v_WorldNormal;
+layout(location = 2) out vec2 v_Uv;
+
+layout(set = 0, binding = 0) uniform View {
+    mat4 ViewProj;
+    vec3 ViewWorldPosition;
+};
+
+layout(set = 1, binding = 0) uniform MeshTransform {
+    mat4 Model;
+};
+
+void main() {
+    v_Uv = Vertex_Uv;
+    v_WorldPosition = Model * vec4(Vertex_Position, 1.0);
+    v_WorldNormal = mat3(Model) * Vertex_Normal;
+    gl_Position = ViewProj * v_WorldPosition;
+}

pipelined/bevy_render2/Cargo.toml

@@ -39,7 +39,6 @@ anyhow = "1.0"
 hex = "0.4.2"
 hexasphere = "3.4"
 parking_lot = "0.11.0"
-raw-window-handle = "0.3.0"
 crevice = { path = "../../crates/crevice" }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]

pipelined/bevy_render2/changes.md

@@ -0,0 +1,6 @@
+* SubGraphs: Graphs can own other named graphs
+* Graph Inputs: Graphs can now have "inputs". These are represented as a single input node, so inputs can be connected to other node slots using the existing apis.
+* RenderGraph is now a static specification. No run state is stored
+* Graph Nodes impls can only read their internal state when "running". This ensures that they can be used multiple times in parallel. State should be stored in World.
+* RenderGraphContext now handles graph inputs and outputs
+* Removed RenderGraphStager, RenderGraphExecutor, stager impls, and WgpuRenderGraphExecutor. It is now 100% the render backend's job to decide how to run the RenderGraph ... bevy_render doesn't provide any tools for this. 

pipelined/bevy_render2/src/camera/bundle.rs

@@ -1,6 +1,6 @@
 use crate::camera::{
-    Camera, DepthCalculation, OrthographicProjection, PerspectiveProjection, ScalingMode,
-    CAMERA_2D, CAMERA_3D,
+    Camera, CameraPlugin, DepthCalculation, OrthographicProjection, PerspectiveProjection,
+    ScalingMode,
 };
 use bevy_ecs::bundle::Bundle;
 use bevy_transform::components::{GlobalTransform, Transform};
@@ -38,7 +38,7 @@ impl Default for PerspectiveCameraBundle {
     fn default() -> Self {
         PerspectiveCameraBundle {
             camera: Camera {
-                name: Some(CAMERA_3D.to_string()),
+                name: Some(CameraPlugin::CAMERA_3D.to_string()),
                 ..Default::default()
             },
             perspective_projection: Default::default(),
@@ -66,7 +66,7 @@ impl OrthographicCameraBundle {
         let far = 1000.0;
         OrthographicCameraBundle {
             camera: Camera {
-                name: Some(CAMERA_2D.to_string()),
+                name: Some(CameraPlugin::CAMERA_2D.to_string()),
                 ..Default::default()
             },
             orthographic_projection: OrthographicProjection {
@@ -82,7 +82,7 @@ impl OrthographicCameraBundle {
     pub fn new_3d() -> Self {
         OrthographicCameraBundle {
             camera: Camera {
-                name: Some(CAMERA_3D.to_string()),
+                name: Some(CameraPlugin::CAMERA_3D.to_string()),
                 ..Default::default()
             },
             orthographic_projection: OrthographicProjection {

pipelined/bevy_render2/src/camera/camera.rs

@@ -1,8 +1,9 @@
-use super::CameraProjection;
+use crate::camera::CameraProjection;
 use bevy_ecs::{
     component::Component,
     entity::Entity,
     event::EventReader,
+    prelude::DetectChanges,
     query::Added,
     reflect::ReflectComponent,
     system::{Query, QuerySet, Res},

pipelined/bevy_render2/src/camera/mod.rs

@@ -7,31 +7,28 @@ mod projection;
 pub use active_cameras::*;
 use bevy_transform::components::GlobalTransform;
 use bevy_utils::HashMap;
+use bevy_window::{WindowId, Windows};
 pub use bundle::*;
 pub use camera::*;
 pub use projection::*;
 
-use crate::{
-    render_graph::{Node, RenderGraph, ResourceSlots},
-    render_resource::{DynamicUniformVec, RenderResourceBinding},
-    renderer::{RenderContext, RenderResources},
-    RenderStage,
-};
+use crate::{view::ExtractedView, RenderStage};
 use bevy_app::{App, CoreStage, Plugin};
 use bevy_ecs::prelude::*;
-use bevy_math::Mat4;
-
-pub const CAMERA_2D: &str = "camera_2d";
-pub const CAMERA_3D: &str = "camera_3d";
 
 #[derive(Default)]
 pub struct CameraPlugin;
 
+impl CameraPlugin {
+    pub const CAMERA_2D: &'static str = "camera_2d";
+    pub const CAMERA_3D: &'static str = "camera_3d";
+}
+
 impl Plugin for CameraPlugin {
     fn build(&self, app: &mut App) {
         let mut active_cameras = ActiveCameras::default();
-        active_cameras.add(CAMERA_2D);
-        active_cameras.add(CAMERA_3D);
+        active_cameras.add(Self::CAMERA_2D);
+        active_cameras.add(Self::CAMERA_3D);
         app.register_type::<Camera>()
             .insert_resource(active_cameras)
             .add_system_to_stage(
@@ -41,91 +38,56 @@ impl Plugin for CameraPlugin {
             .add_system_to_stage(
                 CoreStage::PostUpdate,
                 crate::camera::camera_system::<OrthographicProjection>.system(),
+            )
+            .add_system_to_stage(
+                CoreStage::PostUpdate,
+                crate::camera::camera_system::<PerspectiveProjection>.system(),
             );
         let render_app = app.sub_app_mut(0);
         render_app
-            .init_resource::<Cameras>()
-            .add_system_to_stage(RenderStage::Extract, extract_cameras.system())
-            .add_system_to_stage(RenderStage::Prepare, prepare_cameras.system());
-        let mut graph = render_app.world.get_resource_mut::<RenderGraph>().unwrap();
-        graph.add_node("camera", CameraNode);
+            .init_resource::<ExtractedCameraNames>()
+            .add_system_to_stage(RenderStage::Extract, extract_cameras.system());
     }
 }
 
 #[derive(Default)]
-pub struct Cameras {
-    pub view_proj_uniforms: DynamicUniformVec<Mat4>,
+pub struct ExtractedCameraNames {
     pub entities: HashMap<String, Entity>,
 }
 
 #[derive(Debug)]
 pub struct ExtractedCamera {
-    pub projection: Mat4,
-    pub transform: Mat4,
+    pub window_id: WindowId,
     pub name: Option<String>,
 }
 
-pub struct CameraUniforms {
-    pub view_proj: RenderResourceBinding,
-}
-
 fn extract_cameras(
     mut commands: Commands,
     active_cameras: Res<ActiveCameras>,
-    query: Query<(&Camera, &GlobalTransform)>,
+    windows: Res<Windows>,
+    query: Query<(Entity, &Camera, &GlobalTransform)>,
 ) {
+    let mut entities = HashMap::default();
     for camera in active_cameras.iter() {
-        if let Some((camera, transform)) = camera.entity.and_then(|e| query.get(e).ok()) {
-            // TODO: remove "spawn_and_forget" hack in favor of more intelligent multiple world handling
-            commands.spawn_and_forget((ExtractedCamera {
-                projection: camera.projection_matrix,
-                transform: transform.compute_matrix(),
+        let name = &camera.name;
+        if let Some((entity, camera, transform)) = camera.entity.and_then(|e| query.get(e).ok()) {
+            entities.insert(name.clone(), entity);
+            if let Some(window) = windows.get(camera.window) {
+                commands.get_or_spawn(entity).insert_bundle((
+                    ExtractedCamera {
+                        window_id: camera.window,
                         name: camera.name.clone(),
-            },));
+                    },
+                    ExtractedView {
+                        projection: camera.projection_matrix,
+                        transform: transform.clone(),
+                        width: window.physical_width(),
+                        height: window.physical_height(),
+                    },
+                ));
             }
         }
     }
 
-fn prepare_cameras(
-    mut commands: Commands,
-    render_resources: Res<RenderResources>,
-    mut cameras: ResMut<Cameras>,
-    mut extracted_cameras: Query<(Entity, &ExtractedCamera)>,
-) {
-    cameras.entities.clear();
-    cameras
-        .view_proj_uniforms
-        .reserve_and_clear(extracted_cameras.iter_mut().len(), &render_resources);
-    for (entity, camera) in extracted_cameras.iter() {
-        let camera_uniforms = CameraUniforms {
-            view_proj: cameras
-                .view_proj_uniforms
-                .push(camera.projection * camera.transform.inverse()),
-        };
-        commands.entity(entity).insert(camera_uniforms);
-        if let Some(name) = camera.name.as_ref() {
-            cameras.entities.insert(name.to_string(), entity);
-        }
-    }
-
-    cameras
-        .view_proj_uniforms
-        .write_to_staging_buffer(&render_resources);
-}
-
-pub struct CameraNode;
-
-impl Node for CameraNode {
-    fn update(
-        &mut self,
-        world: &World,
-        render_context: &mut dyn RenderContext,
-        _input: &ResourceSlots,
-        _output: &mut ResourceSlots,
-    ) {
-        let camera_uniforms = world.get_resource::<Cameras>().unwrap();
-        camera_uniforms
-            .view_proj_uniforms
-            .write_to_uniform_buffer(render_context);
-    }
+    commands.insert_resource(ExtractedCameraNames { entities })
 }

pipelined/bevy_render2/src/core_pipeline/main_pass_2d.rs

@@ -0,0 +1,89 @@
+use crate::{
+    color::Color,
+    core_pipeline::Transparent2dPhase,
+    pass::{
+        LoadOp, Operations, PassDescriptor, RenderPass, RenderPassColorAttachment,
+        TextureAttachment,
+    },
+    render_graph::{Node, NodeRunError, RenderGraphContext, SlotInfo, SlotType},
+    render_phase::{DrawFunctions, RenderPhase, TrackedRenderPass},
+    renderer::RenderContext,
+    view::ExtractedView,
+};
+use bevy_ecs::prelude::*;
+
+pub struct MainPass2dNode {
+    query: QueryState<&'static RenderPhase<Transparent2dPhase>, With<ExtractedView>>,
+}
+
+impl MainPass2dNode {
+    pub const IN_COLOR_ATTACHMENT: &'static str = "color_attachment";
+    pub const IN_VIEW: &'static str = "view";
+
+    pub fn new(world: &mut World) -> Self {
+        Self {
+            query: QueryState::new(world),
+        }
+    }
+}
+
+impl Node for MainPass2dNode {
+    fn input(&self) -> Vec<SlotInfo> {
+        vec![
+            SlotInfo::new(MainPass2dNode::IN_COLOR_ATTACHMENT, SlotType::TextureView),
+            SlotInfo::new(MainPass2dNode::IN_VIEW, SlotType::Entity),
+        ]
+    }
+
+    fn update(&mut self, world: &mut World) {
+        self.query.update_archetypes(world);
+    }
+
+    fn run(
+        &self,
+        graph: &mut RenderGraphContext,
+        render_context: &mut dyn RenderContext,
+        world: &World,
+    ) -> Result<(), NodeRunError> {
+        let color_attachment_texture = graph.get_input_texture(Self::IN_COLOR_ATTACHMENT)?;
+        let pass_descriptor = PassDescriptor {
+            color_attachments: vec![RenderPassColorAttachment {
+                attachment: TextureAttachment::Id(color_attachment_texture),
+                resolve_target: None,
+                ops: Operations {
+                    load: LoadOp::Clear(Color::rgb(0.4, 0.4, 0.4)),
+                    store: true,
+                },
+            }],
+            depth_stencil_attachment: None,
+            sample_count: 1,
+        };
+
+        let view_entity = graph.get_input_entity(Self::IN_VIEW)?;
+        let draw_functions = world.get_resource::<DrawFunctions>().unwrap();
+
+        let transparent_phase = self
+            .query
+            .get_manual(world, view_entity)
+            .expect("view entity should exist");
+
+        render_context.begin_render_pass(
+            &pass_descriptor,
+            &mut |render_pass: &mut dyn RenderPass| {
+                let mut draw_functions = draw_functions.write();
+                let mut tracked_pass = TrackedRenderPass::new(render_pass);
+                for drawable in transparent_phase.drawn_things.iter() {
+                    let draw_function = draw_functions.get_mut(drawable.draw_function).unwrap();
+                    draw_function.draw(
+                        world,
+                        &mut tracked_pass,
+                        view_entity,
+                        drawable.draw_key,
+                        drawable.sort_key,
+                    );
+                }
+            },
+        );
+        Ok(())
+    }
+}

pipelined/bevy_render2/src/core_pipeline/main_pass_3d.rs

@@ -0,0 +1,99 @@
+use crate::{
+    color::Color,
+    core_pipeline::Transparent3dPhase,
+    pass::{
+        LoadOp, Operations, PassDescriptor, RenderPass, RenderPassColorAttachment,
+        RenderPassDepthStencilAttachment, TextureAttachment,
+    },
+    render_graph::{Node, NodeRunError, RenderGraphContext, SlotInfo, SlotType},
+    render_phase::{DrawFunctions, RenderPhase, TrackedRenderPass},
+    renderer::RenderContext,
+    view::ExtractedView,
+};
+use bevy_ecs::prelude::*;
+
+pub struct MainPass3dNode {
+    query: QueryState<&'static RenderPhase<Transparent3dPhase>, With<ExtractedView>>,
+}
+
+impl MainPass3dNode {
+    pub const IN_COLOR_ATTACHMENT: &'static str = "color_attachment";
+    pub const IN_DEPTH: &'static str = "depth";
+    pub const IN_VIEW: &'static str = "view";
+
+    pub fn new(world: &mut World) -> Self {
+        Self {
+            query: QueryState::new(world),
+        }
+    }
+}
+
+impl Node for MainPass3dNode {
+    fn input(&self) -> Vec<SlotInfo> {
+        vec![
+            SlotInfo::new(MainPass3dNode::IN_COLOR_ATTACHMENT, SlotType::TextureView),
+            SlotInfo::new(MainPass3dNode::IN_DEPTH, SlotType::TextureView),
+            SlotInfo::new(MainPass3dNode::IN_VIEW, SlotType::Entity),
+        ]
+    }
+
+    fn update(&mut self, world: &mut World) {
+        self.query.update_archetypes(world);
+    }
+
+    fn run(
+        &self,
+        graph: &mut RenderGraphContext,
+        render_context: &mut dyn RenderContext,
+        world: &World,
+    ) -> Result<(), NodeRunError> {
+        let color_attachment_texture = graph.get_input_texture(Self::IN_COLOR_ATTACHMENT)?;
+        let depth_texture = graph.get_input_texture(Self::IN_DEPTH)?;
+        let pass_descriptor = PassDescriptor {
+            color_attachments: vec![RenderPassColorAttachment {
+                attachment: TextureAttachment::Id(color_attachment_texture),
+                resolve_target: None,
+                ops: Operations {
+                    load: LoadOp::Clear(Color::rgb(0.4, 0.4, 0.4)),
+                    store: true,
+                },
+            }],
+            depth_stencil_attachment: Some(RenderPassDepthStencilAttachment {
+                attachment: TextureAttachment::Id(depth_texture),
+                depth_ops: Some(Operations {
+                    load: LoadOp::Clear(1.0),
+                    store: true,
+                }),
+                stencil_ops: None,
+            }),
+            sample_count: 1,
+        };
+
+        let view_entity = graph.get_input_entity(Self::IN_VIEW)?;
+        let draw_functions = world.get_resource::<DrawFunctions>().unwrap();
+
+        let transparent_phase = self
+            .query
+            .get_manual(world, view_entity)
+            .expect("view entity should exist");
+
+        render_context.begin_render_pass(
+            &pass_descriptor,
+            &mut |render_pass: &mut dyn RenderPass| {
+                let mut draw_functions = draw_functions.write();
+                let mut tracked_pass = TrackedRenderPass::new(render_pass);
+                for drawable in transparent_phase.drawn_things.iter() {
+                    let draw_function = draw_functions.get_mut(drawable.draw_function).unwrap();
+                    draw_function.draw(
+                        world,
+                        &mut tracked_pass,
+                        view_entity,
+                        drawable.draw_key,
+                        drawable.sort_key,
+                    );
+                }
+            },
+        );
+        Ok(())
+    }
+}

pipelined/bevy_render2/src/core_pipeline/main_pass_driver.rs

@@ -0,0 +1,52 @@
+use crate::{
+    camera::{CameraPlugin, ExtractedCamera, ExtractedCameraNames},
+    core_pipeline::{self, ViewDepthTexture},
+    render_graph::{Node, NodeRunError, RenderGraphContext, SlotValue},
+    renderer::RenderContext,
+    view::ExtractedWindows,
+};
+use bevy_ecs::world::World;
+
+pub struct MainPassDriverNode;
+
+impl Node for MainPassDriverNode {
+    fn run(
+        &self,
+        graph: &mut RenderGraphContext,
+        _render_context: &mut dyn RenderContext,
+        world: &World,
+    ) -> Result<(), NodeRunError> {
+        let extracted_cameras = world.get_resource::<ExtractedCameraNames>().unwrap();
+        let extracted_windows = world.get_resource::<ExtractedWindows>().unwrap();
+
+        if let Some(camera_2d) = extracted_cameras.entities.get(CameraPlugin::CAMERA_2D) {
+            let extracted_camera = world.entity(*camera_2d).get::<ExtractedCamera>().unwrap();
+            let extracted_window = extracted_windows.get(&extracted_camera.window_id).unwrap();
+            let swap_chain_texture = extracted_window.swap_chain_texture.unwrap();
+            graph.run_sub_graph(
+                core_pipeline::draw_2d_graph::NAME,
+                vec![
+                    SlotValue::Entity(*camera_2d),
+                    SlotValue::TextureView(swap_chain_texture),
+                ],
+            )?;
+        }
+
+        if let Some(camera_3d) = extracted_cameras.entities.get(CameraPlugin::CAMERA_3D) {
+            let extracted_camera = world.entity(*camera_3d).get::<ExtractedCamera>().unwrap();
+            let depth_texture = world.entity(*camera_3d).get::<ViewDepthTexture>().unwrap();
+            let extracted_window = extracted_windows.get(&extracted_camera.window_id).unwrap();
+            let swap_chain_texture = extracted_window.swap_chain_texture.unwrap();
+            graph.run_sub_graph(
+                core_pipeline::draw_3d_graph::NAME,
+                vec![
+                    SlotValue::Entity(*camera_3d),
+                    SlotValue::TextureView(swap_chain_texture),
+                    SlotValue::TextureView(depth_texture.view),
+                ],
+            )?;
+        }
+
+        Ok(())
+    }
+}

pipelined/bevy_render2/src/core_pipeline/mod.rs

@@ -0,0 +1,214 @@
+mod main_pass_2d;
+mod main_pass_3d;
+mod main_pass_driver;
+
+pub use main_pass_2d::*;
+pub use main_pass_3d::*;
+pub use main_pass_driver::*;
+
+use crate::{
+    camera::{ActiveCameras, CameraPlugin},
+    render_command::RenderCommandPlugin,
+    render_graph::{EmptyNode, RenderGraph, SlotInfo, SlotType},
+    render_phase::{sort_phase_system, RenderPhase},
+    render_resource::{TextureId, TextureViewId},
+    renderer::RenderResources,
+    texture::{
+        Extent3d, TextureCache, TextureDescriptor, TextureDimension, TextureFormat, TextureUsage,
+    },
+    view::{ExtractedView, ViewPlugin},
+    RenderStage,
+};
+use bevy_app::{App, Plugin};
+use bevy_ecs::prelude::*;
+
+// Plugins that contribute to the RenderGraph should use the following label conventions:
+// 1. Graph modules should have a NAME, input module, and node module (where relevant)
+// 2. The "top level" graph is the plugin module root. Just add things like `pub mod node` directly under the plugin module
+// 3. "sub graph" modules should be nested beneath their parent graph module
+
+pub mod node {
+    pub const MAIN_PASS_DEPENDENCIES: &'static str = "main_pass_dependencies";
+    pub const MAIN_PASS_DRIVER: &'static str = "main_pass_driver";
+    pub const VIEW: &'static str = "view";
+}
+
+pub mod draw_2d_graph {
+    pub const NAME: &'static str = "draw_2d";
+    pub mod input {
+        pub const VIEW_ENTITY: &'static str = "view_entity";
+        pub const RENDER_TARGET: &'static str = "render_target";
+    }
+    pub mod node {
+        pub const MAIN_PASS: &'static str = "main_pass";
+    }
+}
+
+pub mod draw_3d_graph {
+    pub const NAME: &'static str = "draw_3d";
+    pub mod input {
+        pub const VIEW_ENTITY: &'static str = "view_entity";
+        pub const RENDER_TARGET: &'static str = "render_target";
+        pub const DEPTH: &'static str = "depth";
+    }
+    pub mod node {
+        pub const MAIN_PASS: &'static str = "main_pass";
+    }
+}
+
+#[derive(Default)]
+pub struct CorePipelinePlugin;
+
+impl Plugin for CorePipelinePlugin {
+    fn build(&self, app: &mut App) {
+        let render_app = app.sub_app_mut(0);
+        render_app
+            .add_system_to_stage(
+                RenderStage::Extract,
+                extract_core_pipeline_camera_phases.system(),
+            )
+            .add_system_to_stage(RenderStage::Prepare, prepare_core_views_system.system())
+            .add_system_to_stage(
+                RenderStage::PhaseSort,
+                sort_phase_system::<Transparent2dPhase>.system(),
+            )
+            .add_system_to_stage(
+                RenderStage::PhaseSort,
+                sort_phase_system::<Transparent3dPhase>.system(),
+            );
+
+        let pass_node_2d = MainPass2dNode::new(&mut render_app.world);
+        let pass_node_3d = MainPass3dNode::new(&mut render_app.world);
+        let mut graph = render_app.world.get_resource_mut::<RenderGraph>().unwrap();
+
+        let mut draw_2d_graph = RenderGraph::default();
+        draw_2d_graph.add_node(draw_2d_graph::node::MAIN_PASS, pass_node_2d);
+        let input_node_id = draw_2d_graph.set_input(vec![
+            SlotInfo::new(draw_2d_graph::input::VIEW_ENTITY, SlotType::Entity),
+            SlotInfo::new(draw_2d_graph::input::RENDER_TARGET, SlotType::TextureView),
+        ]);
+        draw_2d_graph
+            .add_slot_edge(
+                input_node_id,
+                draw_2d_graph::input::VIEW_ENTITY,
+                draw_2d_graph::node::MAIN_PASS,
+                MainPass2dNode::IN_VIEW,
+            )
+            .unwrap();
+        draw_2d_graph
+            .add_slot_edge(
+                input_node_id,
+                draw_2d_graph::input::RENDER_TARGET,
+                draw_2d_graph::node::MAIN_PASS,
+                MainPass2dNode::IN_COLOR_ATTACHMENT,
+            )
+            .unwrap();
+        graph.add_sub_graph(draw_2d_graph::NAME, draw_2d_graph);
+
+        let mut draw_3d_graph = RenderGraph::default();
+        draw_3d_graph.add_node(draw_3d_graph::node::MAIN_PASS, pass_node_3d);
+        let input_node_id = draw_3d_graph.set_input(vec![
+            SlotInfo::new(draw_3d_graph::input::VIEW_ENTITY, SlotType::Entity),
+            SlotInfo::new(draw_3d_graph::input::RENDER_TARGET, SlotType::TextureView),
+            SlotInfo::new(draw_3d_graph::input::DEPTH, SlotType::TextureView),
+        ]);
+        draw_3d_graph
+            .add_slot_edge(
+                input_node_id,
+                draw_3d_graph::input::VIEW_ENTITY,
+                draw_3d_graph::node::MAIN_PASS,
+                MainPass3dNode::IN_VIEW,
+            )
+            .unwrap();
+        draw_3d_graph
+            .add_slot_edge(
+                input_node_id,
+                draw_3d_graph::input::RENDER_TARGET,
+                draw_3d_graph::node::MAIN_PASS,
+                MainPass3dNode::IN_COLOR_ATTACHMENT,
+            )
+            .unwrap();
+        draw_3d_graph
+            .add_slot_edge(
+                input_node_id,
+                draw_3d_graph::input::DEPTH,
+                draw_3d_graph::node::MAIN_PASS,
+                MainPass3dNode::IN_DEPTH,
+            )
+            .unwrap();
+        graph.add_sub_graph(draw_3d_graph::NAME, draw_3d_graph);
+
+        graph.add_node(node::MAIN_PASS_DEPENDENCIES, EmptyNode);
+        graph.add_node(node::MAIN_PASS_DRIVER, MainPassDriverNode);
+        graph
+            .add_node_edge(ViewPlugin::VIEW_NODE, node::MAIN_PASS_DEPENDENCIES)
+            .unwrap();
+        graph
+            .add_node_edge(
+                RenderCommandPlugin::RENDER_COMMAND_QUEUE_NODE,
+                node::MAIN_PASS_DEPENDENCIES,
+            )
+            .unwrap();
+        graph
+            .add_node_edge(node::MAIN_PASS_DEPENDENCIES, node::MAIN_PASS_DRIVER)
+            .unwrap();
+    }
+}
+
+pub struct Transparent3dPhase;
+pub struct Transparent2dPhase;
+
+pub struct ViewDepthTexture {
+    pub texture: TextureId,
+    pub view: TextureViewId,
+}
+
+pub fn extract_core_pipeline_camera_phases(
+    mut commands: Commands,
+    active_cameras: Res<ActiveCameras>,
+) {
+    if let Some(camera_2d) = active_cameras.get(CameraPlugin::CAMERA_2D) {
+        if let Some(entity) = camera_2d.entity {
+            commands
+                .get_or_spawn(entity)
+                .insert(RenderPhase::<Transparent2dPhase>::default());
+        }
+    }
+    if let Some(camera_3d) = active_cameras.get(CameraPlugin::CAMERA_3D) {
+        if let Some(entity) = camera_3d.entity {
+            commands
+                .get_or_spawn(entity)
+                .insert(RenderPhase::<Transparent3dPhase>::default());
+        }
+    }
+}
+
+pub fn prepare_core_views_system(
+    mut commands: Commands,
+    mut texture_cache: ResMut<TextureCache>,
+    render_resources: Res<RenderResources>,
+    views: Query<(Entity, &ExtractedView), With<RenderPhase<Transparent3dPhase>>>,
+) {
+    for (entity, view) in views.iter() {
+        let cached_texture = texture_cache.get(
+            &render_resources,
+            TextureDescriptor {
+                size: Extent3d {
+                    depth_or_array_layers: 1,
+                    width: view.width as u32,
+                    height: view.height as u32,
+                },
+                mip_level_count: 1,
+                sample_count: 1,
+                dimension: TextureDimension::D2,
+                format: TextureFormat::Depth32Float, /* PERF: vulkan docs recommend using 24
+                                                      * bit depth for better performance */
+                usage: TextureUsage::RENDER_ATTACHMENT,
+            },
+        );
+        commands.entity(entity).insert(ViewDepthTexture {
+            texture: cached_texture.texture,
+            view: cached_texture.default_view,
+        });
+    }
+}

pipelined/bevy_render2/src/lib.rs

@@ -1,21 +1,29 @@
 pub mod camera;
 pub mod color;
-pub mod main_pass;
+pub mod core_pipeline;
 pub mod mesh;
 pub mod pass;
 pub mod pipeline;
 pub mod render_command;
 pub mod render_graph;
+pub mod render_phase;
 pub mod render_resource;
 pub mod renderer;
 pub mod shader;
 pub mod texture;
+pub mod view;
 
 pub use once_cell;
 
 use crate::{
-    render_command::RenderCommandPlugin, render_graph::RenderGraph, renderer::RenderResources,
+    camera::CameraPlugin,
+    mesh::MeshPlugin,
+    render_command::RenderCommandPlugin,
+    render_graph::RenderGraph,
+    render_phase::DrawFunctions,
+    renderer::RenderResources,
     texture::TexturePlugin,
+    view::{ViewPlugin, WindowRenderPlugin},
 };
 use bevy_app::{App, Plugin, StartupStage};
 use bevy_ecs::prelude::*;
@@ -38,8 +46,15 @@ pub enum RenderStage {
     /// Create Bind Groups that depend on Prepare data and queue up draw calls to run during the Render stage.
     Queue,
 
+    // TODO: This could probably be moved in favor of a system ordering abstraction in Render or Queue
+    /// Sort RenderPhases here 
+    PhaseSort,
+
     /// Actual rendering happens here. In most cases, only the render backend should insert resources here
     Render,
+
+    /// Cleanup render resources here.
+    Cleanup,
 }
 
 impl Plugin for RenderPlugin {
@@ -57,9 +72,25 @@ impl Plugin for RenderPlugin {
             .add_stage(RenderStage::Extract, extract_stage)
             .add_stage(RenderStage::Prepare, SystemStage::parallel())
             .add_stage(RenderStage::Queue, SystemStage::parallel())
-            .add_stage(RenderStage::Render, SystemStage::parallel());
-        render_app.insert_resource(RenderGraph::default());
+            .add_stage(RenderStage::PhaseSort, SystemStage::parallel())
+            .add_stage(RenderStage::Render, SystemStage::parallel())
+            .add_stage(RenderStage::Cleanup, SystemStage::parallel())
+            .init_resource::<RenderGraph>()
+            .init_resource::<DrawFunctions>();
+
         app.add_sub_app(render_app, |app_world, render_app| {
+            // reserve all existing app entities for use in render_app
+            // they can only be spawned using `get_or_spawn()`
+            let meta_len = app_world.entities().meta.len();
+            render_app
+                .world
+                .entities()
+                .reserve_entities(meta_len as u32);
+            // flushing as "invalid" ensures that app world entities aren't added as "empty archetype" entities by default
+            // these entities cannot be accessed without spawning directly onto them
+            // this _only_ works as expected because clear_entities() is called at the end of every frame.
+            render_app.world.entities_mut().flush_as_invalid();
+
             // extract
             extract(app_world, render_app);
 
@@ -77,6 +108,13 @@ impl Plugin for RenderPlugin {
                 .unwrap();
             queue.run(&mut render_app.world);
 
+            // phase sort
+            let phase_sort = render_app
+                .schedule
+                .get_stage_mut::<SystemStage>(&RenderStage::PhaseSort)
+                .unwrap();
+            phase_sort.run(&mut render_app.world);
+
             // render
             let render = render_app
                 .schedule
@@ -84,10 +122,21 @@ impl Plugin for RenderPlugin {
                 .unwrap();
             render.run(&mut render_app.world);
 
+            // cleanup
+            let cleanup = render_app
+                .schedule
+                .get_stage_mut::<SystemStage>(&RenderStage::Cleanup)
+                .unwrap();
+            cleanup.run(&mut render_app.world);
+
             render_app.world.clear_entities();
         });
 
         app.add_plugin(RenderCommandPlugin)
+            .add_plugin(WindowRenderPlugin)
+            .add_plugin(CameraPlugin)
+            .add_plugin(ViewPlugin)
+            .add_plugin(MeshPlugin)
             .add_plugin(TexturePlugin);
     }
 }

pipelined/bevy_render2/src/main_pass/draw.rs

@@ -1,26 +0,0 @@
-use crate::main_pass::TrackedRenderPass;
-use bevy_ecs::world::World;
-use parking_lot::Mutex;
-
-// TODO: should this be generic on "drawn thing"? would provide more flexibility and  explicitness
-// instead of hard coded draw key and sort key
-pub trait Draw: Send + Sync + 'static {
-    fn draw(
-        &mut self,
-        world: &World,
-        pass: &mut TrackedRenderPass,
-        draw_key: usize,
-        sort_key: usize,
-    );
-}
-
-#[derive(Default)]
-pub struct DrawFunctions {
-    pub draw_function: Mutex<Vec<Box<dyn Draw>>>,
-}
-
-impl DrawFunctions {
-    pub fn add<D: Draw>(&self, draw_function: D) {
-        self.draw_function.lock().push(Box::new(draw_function));
-    }
-}

pipelined/bevy_render2/src/main_pass/mod.rs

@@ -1,136 +0,0 @@
-mod draw;
-mod draw_state;
-
-pub use draw::*;
-pub use draw_state::*;
-
-use crate::{
-    camera::CameraPlugin,
-    color::Color,
-    pass::{LoadOp, Operations, PassDescriptor, RenderPass, TextureAttachment},
-    render_graph::{Node, RenderGraph, ResourceSlotInfo, ResourceSlots, WindowSwapChainNode},
-    render_resource::RenderResourceType,
-};
-use crate::{pass::RenderPassColorAttachment, renderer::RenderContext, RenderStage};
-use bevy_app::{App, Plugin};
-use bevy_ecs::prelude::*;
-use bevy_window::WindowId;
-use std::borrow::Cow;
-
-#[derive(Default)]
-pub struct MainPassPlugin;
-
-impl Plugin for MainPassPlugin {
-    fn build(&self, app: &mut App) {
-        // TODO: this should probably just be a dependency
-        app.add_plugin(CameraPlugin);
-        app.sub_app_mut(0)
-            .add_system_to_stage(
-                RenderStage::Prepare,
-                clear_transparent_phase.exclusive_system().at_start(),
-            )
-            .init_resource::<RenderPhase>()
-            .init_resource::<DrawFunctions>();
-        let render_world = app.sub_app_mut(0).world.cell();
-        let mut graph = render_world.get_resource_mut::<RenderGraph>().unwrap();
-        graph.add_node("main_pass", MainPassNode);
-        graph.add_node_edge("camera", "main_pass").unwrap();
-        graph.add_node(
-            "primary_swap_chain",
-            WindowSwapChainNode::new(WindowId::primary()),
-        );
-        graph
-            .add_slot_edge(
-                "primary_swap_chain",
-                WindowSwapChainNode::OUT_TEXTURE,
-                "main_pass",
-                MainPassNode::IN_COLOR_ATTACHMENT,
-            )
-            .unwrap();
-    }
-}
-
-// TODO: sort out the best place for this
-fn clear_transparent_phase(mut transparent_phase: ResMut<RenderPhase>) {
-    // TODO: TRANSPARENT PHASE SHOULD NOT BE CLEARED HERE!
-    transparent_phase.drawn_things.clear();
-}
-
-pub struct Drawable {
-    pub draw_function: usize,
-    pub draw_key: usize,
-    pub sort_key: usize,
-}
-
-#[derive(Default)]
-pub struct RenderPhase {
-    drawn_things: Vec<Drawable>,
-}
-
-impl RenderPhase {
-    #[inline]
-    pub fn add(&mut self, drawable: Drawable) {
-        self.drawn_things.push(drawable);
-    }
-
-    pub fn sort(&mut self) {
-        self.drawn_things.sort_by_key(|d| d.sort_key);
-    }
-}
-
-pub struct MainPassNode;
-
-impl MainPassNode {
-    pub const IN_COLOR_ATTACHMENT: &'static str = "color_attachment";
-}
-
-impl Node for MainPassNode {
-    fn input(&self) -> &[ResourceSlotInfo] {
-        static INPUT: &[ResourceSlotInfo] = &[ResourceSlotInfo {
-            name: Cow::Borrowed(MainPassNode::IN_COLOR_ATTACHMENT),
-            resource_type: RenderResourceType::Texture,
-        }];
-        INPUT
-    }
-    fn update(
-        &mut self,
-        world: &World,
-        render_context: &mut dyn RenderContext,
-        input: &ResourceSlots,
-        _output: &mut ResourceSlots,
-    ) {
-        // TODO: consider adding shorthand like `get_texture(0)`
-        let color_attachment_texture = input.get(0).unwrap().get_texture().unwrap();
-        let pass_descriptor = PassDescriptor {
-            color_attachments: vec![RenderPassColorAttachment {
-                attachment: TextureAttachment::Id(color_attachment_texture),
-                resolve_target: None,
-                ops: Operations {
-                    load: LoadOp::Clear(Color::rgb(0.4, 0.4, 0.4)),
-                    store: true,
-                },
-            }],
-            depth_stencil_attachment: None,
-            sample_count: 1,
-        };
-
-        let transparent_phase = world.get_resource::<RenderPhase>().unwrap();
-        let draw_functions = world.get_resource::<DrawFunctions>().unwrap();
-
-        render_context.begin_render_pass(
-            &pass_descriptor,
-            &mut |render_pass: &mut dyn RenderPass| {
-                let mut draw_functions = draw_functions.draw_function.lock();
-                let mut tracked_pass = TrackedRenderPass::new(render_pass);
-                for drawable in transparent_phase.drawn_things.iter() {
-                    draw_functions[drawable.draw_function].draw(
-                        world,
-                        &mut tracked_pass,
-                        drawable.draw_key,
-                        drawable.sort_key,
-                    );
-                }
-            },
-        )
-    }
-}

pipelined/bevy_render2/src/mesh/mesh.rs

@@ -1,8 +1,14 @@
 mod conversions;
+mod mesh_resource_provider;
 
-use crate::pipeline::{
+pub use mesh_resource_provider::*;
+
+use crate::{
+    pipeline::{
         IndexFormat, InputStepMode, PrimitiveTopology, VertexAttribute, VertexBufferLayout,
         VertexFormat,
+    },
+    render_resource::BufferId,
 };
 use bevy_core::cast_slice;
 use bevy_math::*;
@@ -182,6 +188,13 @@ impl Indices {
             Indices::U32(vec) => IndicesIter::U32(vec.iter()),
         }
     }
+
+    pub fn len(&self) -> usize {
+        match self {
+            Indices::U16(vec) => vec.len(),
+            Indices::U32(vec) => vec.len(),
+        }
+    }
 }
 enum IndicesIter<'a> {
     U16(std::slice::Iter<'a, u16>),
@@ -207,6 +220,13 @@ impl From<&Indices> for IndexFormat {
     }
 }
 
+// TODO: this shouldn't live in the Mesh type
+#[derive(Debug, Clone)]
+pub struct MeshGpuData {
+    pub vertex_buffer: BufferId,
+    pub index_buffer: Option<BufferId>,
+}
+
 // TODO: allow values to be unloaded after been submitting to the GPU to conserve memory
 #[derive(Debug, TypeUuid, Clone)]
 #[uuid = "8ecbac0f-f545-4473-ad43-e1f4243af51e"]
@@ -218,6 +238,7 @@ pub struct Mesh {
     /// which allows easy stable VertexBuffers (i.e. same buffer order)
     attributes: BTreeMap<Cow<'static, str>, VertexAttributeValues>,
     indices: Option<Indices>,
+    gpu_data: Option<MeshGpuData>,
 }
 
 /// Contains geometry in the form of a mesh.
@@ -264,6 +285,7 @@ impl Mesh {
             primitive_topology,
             attributes: Default::default(),
             indices: None,
+            gpu_data: None,
         }
     }
 
@@ -271,6 +293,10 @@ impl Mesh {
         self.primitive_topology
     }
 
+    pub fn gpu_data(&self) -> Option<&MeshGpuData> {
+        self.gpu_data.as_ref()
+    }
+
     /// Sets the data for a vertex attribute (position, normal etc.). The name will
     /// often be one of the associated constants such as [`Mesh::ATTRIBUTE_POSITION`]
     pub fn set_attribute(

pipelined/bevy_render2/src/mesh/mesh/mesh_resource_provider.rs

@@ -0,0 +1,83 @@
+use crate::{
+    mesh::{Mesh, MeshGpuData},
+    render_resource::{BufferInfo, BufferUsage},
+    renderer::{RenderResourceContext, RenderResources},
+};
+use bevy_asset::{AssetEvent, Assets, Handle};
+use bevy_ecs::prelude::*;
+use bevy_utils::HashSet;
+
+fn remove_current_mesh_resources(
+    render_resource_context: &dyn RenderResourceContext,
+    handle: &Handle<Mesh>,
+    meshes: &mut Assets<Mesh>,
+) {
+    if let Some(gpu_data) = meshes.get_mut(handle).and_then(|m| m.gpu_data.take()) {
+        render_resource_context.remove_buffer(gpu_data.vertex_buffer);
+        if let Some(index_buffer) = gpu_data.index_buffer {
+            render_resource_context.remove_buffer(index_buffer);
+        }
+    }
+}
+
+pub fn mesh_resource_provider_system(
+    render_resource_context: Res<RenderResources>,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut mesh_events: EventReader<AssetEvent<Mesh>>,
+) {
+    let mut changed_meshes = HashSet::default();
+    let render_resource_context = &**render_resource_context;
+    for event in mesh_events.iter() {
+        match event {
+            AssetEvent::Created { ref handle } => {
+                changed_meshes.insert(handle.clone_weak());
+            }
+            AssetEvent::Modified { ref handle } => {
+                changed_meshes.insert(handle.clone_weak());
+                // TODO: uncomment this to support mutated meshes
+                // remove_current_mesh_resources(render_resource_context, handle, &mut meshes);
+            }
+            AssetEvent::Removed { ref handle } => {
+                remove_current_mesh_resources(render_resource_context, handle, &mut meshes);
+                // if mesh was modified and removed in the same update, ignore the modification
+                // events are ordered so future modification events are ok
+                changed_meshes.remove(handle);
+            }
+        }
+    }
+
+    // update changed mesh data
+    for changed_mesh_handle in changed_meshes.iter() {
+        if let Some(mesh) = meshes.get_mut(changed_mesh_handle) {
+            // TODO: this avoids creating new meshes each frame because storing gpu data in the mesh flags it as
+            // modified. this prevents hot reloading and therefore can't be used in an actual impl.
+            if mesh.gpu_data.is_some() {
+                continue;
+            }
+
+            let vertex_buffer_data = mesh.get_vertex_buffer_data();
+            let vertex_buffer = render_resource_context.create_buffer_with_data(
+                BufferInfo {
+                    buffer_usage: BufferUsage::VERTEX,
+                    ..Default::default()
+                },
+                &vertex_buffer_data,
+            );
+
+            let index_buffer = mesh.get_index_buffer_bytes().map(|data| {
+                render_resource_context.create_buffer_with_data(
+                    BufferInfo {
+                        buffer_usage: BufferUsage::INDEX,
+                        ..Default::default()
+                    },
+                    &data,
+                )
+            });
+
+            mesh.gpu_data = Some(MeshGpuData {
+                vertex_buffer,
+                index_buffer,
+            });
+        }
+    }
+}

pipelined/bevy_render2/src/mesh/mod.rs

@@ -3,4 +3,19 @@ mod mesh;
 /// Generation for some primitive shape meshes.
 pub mod shape;
 
+use bevy_asset::AddAsset;
 pub use mesh::*;
+
+use bevy_app::{App, CoreStage, Plugin};
+use bevy_ecs::system::IntoSystem;
+
+pub struct MeshPlugin;
+
+impl Plugin for MeshPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_asset::<Mesh>().add_system_to_stage(
+            CoreStage::PostUpdate,
+            mesh_resource_provider_system.system(),
+        );
+    }
+}

pipelined/bevy_render2/src/pass/pass.rs

@@ -1,13 +1,13 @@
-use crate::{color::Color, pass::Operations, render_resource::TextureId};
+use crate::{color::Color, pass::Operations, render_resource::TextureViewId};
 
 #[derive(Debug, Clone)]
 pub enum TextureAttachment {
-    Id(TextureId),
+    Id(TextureViewId),
     Input(String),
 }
 
 impl TextureAttachment {
-    pub fn get_texture_id(&self) -> Option<TextureId> {
+    pub fn get_texture_view_id(&self) -> Option<TextureViewId> {
         if let TextureAttachment::Id(texture_id) = self {
             Some(*texture_id)
         } else {

pipelined/bevy_render2/src/pipeline/bind_group.rs

@@ -1,6 +1,6 @@
 use super::BindingDescriptor;
-use bevy_utils::AHasher;
-use std::hash::{Hash, Hasher};
+use bevy_utils::FixedState;
+use std::hash::{BuildHasher, Hash, Hasher};
 
 #[derive(Clone, Debug, Eq)]
 pub struct BindGroupDescriptor {
@@ -25,7 +25,7 @@ impl BindGroupDescriptor {
     }
 
     pub fn update_id(&mut self) {
-        let mut hasher = AHasher::default();
+        let mut hasher = FixedState::default().build_hasher();
         self.hash(&mut hasher);
         self.id = BindGroupDescriptorId(hasher.finish());
     }

pipelined/bevy_render2/src/pipeline/mod.rs

@@ -1,9 +1,9 @@
 mod bind_group;
 mod binding;
 mod compute_pipeline;
+mod pipeline_layout;
 #[allow(clippy::module_inception)]
 mod render_pipeline;
-mod pipeline_layout;
 mod state_descriptors;
 mod vertex_buffer_descriptor;
 mod vertex_format;
@@ -11,8 +11,8 @@ mod vertex_format;
 pub use bind_group::*;
 pub use binding::*;
 pub use compute_pipeline::*;
-pub use render_pipeline::*;
 pub use pipeline_layout::*;
+pub use render_pipeline::*;
 pub use state_descriptors::*;
 pub use vertex_buffer_descriptor::*;
 pub use vertex_format::*;

pipelined/bevy_render2/src/pipeline/pipeline_layout.rs

@@ -11,12 +11,29 @@ pub struct PipelineLayout {
 }
 
 impl PipelineLayout {
+    // TODO: make direct indexing work to avoid a full scan
     pub fn get_bind_group(&self, index: u32) -> Option<&BindGroupDescriptor> {
         self.bind_groups
             .iter()
             .find(|bind_group| bind_group.index == index)
     }
 
+    pub fn get_bind_group_mut(&mut self, index: u32) -> Option<&mut BindGroupDescriptor> {
+        self.bind_groups
+            .iter_mut()
+            .find(|bind_group| bind_group.index == index)
+    }
+
+    pub fn bind_group(&self, index: u32) -> &BindGroupDescriptor {
+        self.get_bind_group(index)
+            .expect("bind group exists")
+    }
+
+    pub fn bind_group_mut(&mut self, index: u32) -> &mut BindGroupDescriptor {
+        self.get_bind_group_mut(index)
+            .expect("bind group exists")
+    }
+
     pub fn from_shader_layouts(shader_layouts: &mut [ShaderLayout]) -> Self {
         let mut bind_groups = HashMap::<u32, BindGroupDescriptor>::default();
         let mut vertex_buffer_descriptors = Vec::new();
@@ -68,6 +85,12 @@ impl PipelineLayout {
             vertex_buffer_descriptors,
         }
     }
+    
+    pub fn update_bind_group_ids(&mut self) {
+        for bind_group in self.bind_groups.iter_mut() {
+            bind_group.update_id();
+        }
+    }
 }
 
 #[derive(Hash, Clone, Debug, Eq, PartialEq, Ord, PartialOrd)]

pipelined/bevy_render2/src/render_command/mod.rs

@@ -2,7 +2,7 @@ mod render_command_queue;
 pub use render_command_queue::*;
 
 use crate::{
-    render_graph::{Node, RenderGraph, ResourceSlots},
+    render_graph::{Node, NodeRunError, RenderGraph, RenderGraphContext},
     renderer::RenderContext,
     RenderStage,
 };
@@ -12,13 +12,17 @@ use bevy_ecs::prelude::*;
 #[derive(Default)]
 pub struct RenderCommandPlugin;
 
+impl RenderCommandPlugin {
+    pub const RENDER_COMMAND_QUEUE_NODE: &'static str = "render_command_queue";
+}
+
 impl Plugin for RenderCommandPlugin {
     fn build(&self, app: &mut App) {
         app.init_resource::<RenderCommandQueue>();
         let render_app = app.sub_app_mut(0);
         render_app.add_system_to_stage(RenderStage::Extract, extract_render_commands.system());
         let mut graph = render_app.world.get_resource_mut::<RenderGraph>().unwrap();
-        graph.add_node("render_command_queue", RenderCommandQueueNode);
+        graph.add_node(Self::RENDER_COMMAND_QUEUE_NODE, RenderCommandQueueNode);
     }
 }
 
@@ -34,14 +38,14 @@ fn extract_render_commands(
 pub struct RenderCommandQueueNode;
 
 impl Node for RenderCommandQueueNode {
-    fn update(
-        &mut self,
-        world: &World,
+    fn run(
+        &self,
+        _graph: &mut RenderGraphContext,
         render_context: &mut dyn RenderContext,
-        _input: &ResourceSlots,
-        _output: &mut ResourceSlots,
-    ) {
+        world: &World,
+    ) -> Result<(), NodeRunError> {
         let queue = world.get_resource::<RenderCommandQueue>().unwrap();
         queue.execute(render_context);
+        Ok(())
     }
 }

pipelined/bevy_render2/src/render_graph/context.rs

@@ -0,0 +1,234 @@
+use std::borrow::Cow;
+
+use crate::{
+    render_graph::{NodeState, RenderGraph, SlotInfos, SlotLabel, SlotType, SlotValue},
+    render_resource::{BufferId, SamplerId, TextureViewId},
+};
+use bevy_ecs::entity::Entity;
+use thiserror::Error;
+
+pub struct RunSubGraph {
+    pub name: Cow<'static, str>,
+    pub inputs: Vec<SlotValue>,
+}
+
+pub struct RenderGraphContext<'a> {
+    graph: &'a RenderGraph,
+    node: &'a NodeState,
+    inputs: &'a [SlotValue],
+    outputs: &'a mut [Option<SlotValue>],
+    run_sub_graphs: Vec<RunSubGraph>,
+}
+
+impl<'a> RenderGraphContext<'a> {
+    pub fn new(
+        graph: &'a RenderGraph,
+        node: &'a NodeState,
+        inputs: &'a [SlotValue],
+        outputs: &'a mut [Option<SlotValue>],
+    ) -> Self {
+        Self {
+            graph,
+            node,
+            inputs,
+            outputs,
+            run_sub_graphs: Vec::new(),
+        }
+    }
+
+    #[inline]
+    pub fn inputs(&self) -> &[SlotValue] {
+        self.inputs
+    }
+
+    pub fn input_info(&self) -> &SlotInfos {
+        &self.node.input_slots
+    }
+
+    pub fn output_info(&self) -> &SlotInfos {
+        &self.node.output_slots
+    }
+
+    pub fn get_input(&self, label: impl Into<SlotLabel>) -> Result<SlotValue, InputSlotError> {
+        let label = label.into();
+        let index = self
+            .input_info()
+            .get_slot_index(label.clone())
+            .ok_or(InputSlotError::InvalidSlot(label))?;
+        Ok(self.inputs[index])
+    }
+
+    pub fn get_input_texture(
+        &self,
+        label: impl Into<SlotLabel>,
+    ) -> Result<TextureViewId, InputSlotError> {
+        let label = label.into();
+        match self.get_input(label.clone())? {
+            SlotValue::TextureView(value) => Ok(value),
+            value @ _ => Err(InputSlotError::MismatchedSlotType {
+                label,
+                actual: value.slot_type(),
+                expected: SlotType::TextureView,
+            }),
+        }
+    }
+
+    pub fn get_input_sampler(
+        &self,
+        label: impl Into<SlotLabel>,
+    ) -> Result<SamplerId, InputSlotError> {
+        let label = label.into();
+        match self.get_input(label.clone())? {
+            SlotValue::Sampler(value) => Ok(value),
+            value @ _ => Err(InputSlotError::MismatchedSlotType {
+                label,
+                actual: value.slot_type(),
+                expected: SlotType::Sampler,
+            }),
+        }
+    }
+
+    pub fn get_input_buffer(
+        &self,
+        label: impl Into<SlotLabel>,
+    ) -> Result<BufferId, InputSlotError> {
+        let label = label.into();
+        match self.get_input(label.clone())? {
+            SlotValue::Buffer(value) => Ok(value),
+            value @ _ => Err(InputSlotError::MismatchedSlotType {
+                label,
+                actual: value.slot_type(),
+                expected: SlotType::Buffer,
+            }),
+        }
+    }
+
+    pub fn get_input_entity(&self, label: impl Into<SlotLabel>) -> Result<Entity, InputSlotError> {
+        let label = label.into();
+        match self.get_input(label.clone())? {
+            SlotValue::Entity(value) => Ok(value),
+            value @ _ => Err(InputSlotError::MismatchedSlotType {
+                label,
+                actual: value.slot_type(),
+                expected: SlotType::Entity,
+            }),
+        }
+    }
+
+    pub fn set_output(
+        &mut self,
+        label: impl Into<SlotLabel>,
+        value: impl Into<SlotValue>,
+    ) -> Result<(), OutputSlotError> {
+        let label = label.into();
+        let value = value.into();
+        let slot_index = self
+            .output_info()
+            .get_slot_index(label.clone())
+            .ok_or(OutputSlotError::InvalidSlot(label.clone()))?;
+        let slot = self
+            .output_info()
+            .get_slot(slot_index)
+            .expect("slot is valid");
+        if value.slot_type() != slot.slot_type {
+            return Err(OutputSlotError::MismatchedSlotType {
+                label,
+                actual: slot.slot_type,
+                expected: value.slot_type(),
+            });
+        }
+        self.outputs[slot_index] = Some(value);
+        Ok(())
+    }
+
+    pub fn run_sub_graph(
+        &mut self,
+        name: impl Into<Cow<'static, str>>,
+        inputs: Vec<SlotValue>,
+    ) -> Result<(), RunSubGraphError> {
+        let name = name.into();
+        let sub_graph = self
+            .graph
+            .get_sub_graph(&name)
+            .ok_or(RunSubGraphError::MissingSubGraph(name.clone()))?;
+        if let Some(input_node) = sub_graph.input_node() {
+            for (i, input_slot) in input_node.input_slots.iter().enumerate() {
+                if let Some(input_value) = inputs.get(i) {
+                    if input_slot.slot_type != input_value.slot_type() {
+                        return Err(RunSubGraphError::MismatchedInputSlotType {
+                            graph_name: name,
+                            slot_index: i,
+                            actual: input_value.slot_type(),
+                            expected: input_slot.slot_type,
+                            label: input_slot.name.clone().into(),
+                        });
+                    }
+                } else {
+                    return Err(RunSubGraphError::MissingInput {
+                        slot_index: i,
+                        slot_name: input_slot.name.clone(),
+                        graph_name: name,
+                    });
+                }
+            }
+        } else {
+            if !inputs.is_empty() {
+                return Err(RunSubGraphError::SubGraphHasNoInputs(name));
+            }
+        }
+
+        self.run_sub_graphs.push(RunSubGraph { name, inputs });
+
+        Ok(())
+    }
+
+    pub fn finish(self) -> Vec<RunSubGraph> {
+        self.run_sub_graphs
+    }
+}
+
+#[derive(Error, Debug, Eq, PartialEq)]
+pub enum RunSubGraphError {
+    #[error("tried to run a non-existent sub-graph")]
+    MissingSubGraph(Cow<'static, str>),
+    #[error("passed in inputs, but this sub-graph doesn't have any")]
+    SubGraphHasNoInputs(Cow<'static, str>),
+    #[error("sub graph (name: '{graph_name:?}') could not be run because slot '{slot_name}' at index {slot_index} has no value")]
+    MissingInput {
+        slot_index: usize,
+        slot_name: Cow<'static, str>,
+        graph_name: Cow<'static, str>,
+    },
+    #[error("attempted to use the wrong type for input slot")]
+    MismatchedInputSlotType {
+        graph_name: Cow<'static, str>,
+        slot_index: usize,
+        label: SlotLabel,
+        expected: SlotType,
+        actual: SlotType,
+    },
+}
+
+#[derive(Error, Debug, Eq, PartialEq)]
+pub enum OutputSlotError {
+    #[error("slot does not exist")]
+    InvalidSlot(SlotLabel),
+    #[error("attempted to assign the wrong type to slot")]
+    MismatchedSlotType {
+        label: SlotLabel,
+        expected: SlotType,
+        actual: SlotType,
+    },
+}
+
+#[derive(Error, Debug, Eq, PartialEq)]
+pub enum InputSlotError {
+    #[error("slot does not exist")]
+    InvalidSlot(SlotLabel),
+    #[error("attempted to retrieve the wrong type from input slot")]
+    MismatchedSlotType {
+        label: SlotLabel,
+        expected: SlotType,
+        actual: SlotType,
+    },
+}

pipelined/bevy_render2/src/render_graph/graph.rs

@@ -1,4 +1,11 @@
-use super::{Edge, Node, NodeId, NodeLabel, NodeState, RenderGraphError, SlotLabel};
+use crate::{
+    render_graph::{
+        Edge, Node, NodeId, NodeLabel, NodeRunError, NodeState, RenderGraphContext,
+        RenderGraphError, SlotInfo, SlotLabel,
+    },
+    renderer::RenderContext,
+};
+use bevy_ecs::prelude::World;
 use bevy_utils::HashMap;
 use std::{borrow::Cow, fmt::Debug};
 
@@ -6,9 +13,38 @@ use std::{borrow::Cow, fmt::Debug};
 pub struct RenderGraph {
     nodes: HashMap<NodeId, NodeState>,
     node_names: HashMap<Cow<'static, str>, NodeId>,
+    sub_graphs: HashMap<Cow<'static, str>, RenderGraph>,
+    input_node: Option<NodeId>,
 }
 
 impl RenderGraph {
+    pub const INPUT_NODE_NAME: &'static str = "GraphInputNode";
+
+    pub fn update(&mut self, world: &mut World) {
+        for node in self.nodes.values_mut() {
+            node.node.update(world);
+        }
+
+        for sub_graph in self.sub_graphs.values_mut() {
+            sub_graph.update(world);
+        }
+    }
+
+    pub fn set_input(&mut self, inputs: Vec<SlotInfo>) -> NodeId {
+        if self.input_node.is_some() {
+            panic!("Graph already has an input node");
+        }
+
+        let id = self.add_node("GraphInputNode", GraphInputNode { inputs });
+        self.input_node = Some(id);
+        id
+    }
+
+    #[inline]
+    pub fn input_node(&self) -> Option<&NodeState> {
+        self.input_node.and_then(|id| self.get_node_state(id).ok())
+    }
+
     pub fn add_node<T>(&mut self, name: impl Into<Cow<'static, str>>, node: T) -> NodeId
     where
         T: Node,
@@ -80,17 +116,21 @@ impl RenderGraph {
         input_node: impl Into<NodeLabel>,
         input_slot: impl Into<SlotLabel>,
     ) -> Result<(), RenderGraphError> {
+        let output_slot = output_slot.into();
+        let input_slot = input_slot.into();
         let output_node_id = self.get_node_id(output_node)?;
         let input_node_id = self.get_node_id(input_node)?;
 
         let output_index = self
             .get_node_state(output_node_id)?
             .output_slots
-            .get_slot_index(output_slot)?;
+            .get_slot_index(output_slot.clone())
+            .ok_or(RenderGraphError::InvalidOutputNodeSlot(output_slot))?;
         let input_index = self
             .get_node_state(input_node_id)?
             .input_slots
-            .get_slot_index(input_slot)?;
+            .get_slot_index(input_slot.clone())
+            .ok_or(RenderGraphError::InvalidInputNodeSlot(input_slot))?;
 
         let edge = Edge::SlotEdge {
             output_node: output_node_id,
@@ -151,8 +191,18 @@ impl RenderGraph {
                 let output_node_state = self.get_node_state(output_node)?;
                 let input_node_state = self.get_node_state(input_node)?;
 
-                let output_slot = output_node_state.output_slots.get_slot(output_index)?;
-                let input_slot = input_node_state.input_slots.get_slot(input_index)?;
+                let output_slot = output_node_state
+                    .output_slots
+                    .get_slot(output_index)
+                    .ok_or_else(|| {
+                        RenderGraphError::InvalidOutputNodeSlot(SlotLabel::Index(output_index))
+                    })?;
+                let input_slot = input_node_state
+                    .input_slots
+                    .get_slot(input_index)
+                    .ok_or_else(|| {
+                        RenderGraphError::InvalidInputNodeSlot(SlotLabel::Index(input_index))
+                    })?;
 
                 if let Some(Edge::SlotEdge {
                     output_node: current_output_node,
@@ -175,7 +225,7 @@ impl RenderGraph {
                     });
                 }
 
-                if output_slot.resource_type != input_slot.resource_type {
+                if output_slot.slot_type != input_slot.slot_type {
                     return Err(RenderGraphError::MismatchedNodeSlots {
                         output_node,
                         output_slot: output_index,
@@ -241,6 +291,18 @@ impl RenderGraph {
             .map(|edge| (edge, edge.get_input_node()))
             .map(move |(edge, input_node_id)| (edge, self.get_node_state(input_node_id).unwrap())))
     }
+
+    pub fn add_sub_graph(&mut self, name: impl Into<Cow<'static, str>>, sub_graph: RenderGraph) {
+        self.sub_graphs.insert(name.into(), sub_graph);
+    }
+
+    pub fn get_sub_graph(&self, name: impl AsRef<str>) -> Option<&RenderGraph> {
+        self.sub_graphs.get(name.as_ref())
+    }
+
+    pub fn get_sub_graph_mut(&mut self, name: impl AsRef<str>) -> Option<&mut RenderGraph> {
+        self.sub_graphs.get_mut(name.as_ref())
+    }
 }
 
 impl Debug for RenderGraph {
@@ -255,13 +317,40 @@ impl Debug for RenderGraph {
     }
 }
 
+pub struct GraphInputNode {
+    inputs: Vec<SlotInfo>,
+}
+
+impl Node for GraphInputNode {
+    fn input(&self) -> Vec<SlotInfo> {
+        self.inputs.clone()
+    }
+
+    fn output(&self) -> Vec<SlotInfo> {
+        self.inputs.clone()
+    }
+
+    fn run(
+        &self,
+        graph: &mut RenderGraphContext,
+        _render_context: &mut dyn RenderContext,
+        _world: &World,
+    ) -> Result<(), NodeRunError> {
+        for i in 0..graph.inputs().len() {
+            let input = graph.inputs()[i];
+            graph.set_output(i, input)?;
+        }
+        Ok(())
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::{
         render_graph::{
-            Edge, Node, NodeId, RenderGraph, RenderGraphError, ResourceSlotInfo, ResourceSlots,
+            Edge, Node, NodeId, NodeRunError, RenderGraph, RenderGraphContext, RenderGraphError,
+            SlotInfo, SlotType,
         },
-        render_resource::RenderResourceType,
         renderer::RenderContext,
     };
     use bevy_ecs::world::World;
@@ -270,45 +359,39 @@ mod tests {
 
     #[derive(Debug)]
     struct TestNode {
-        inputs: Vec<ResourceSlotInfo>,
-        outputs: Vec<ResourceSlotInfo>,
+        inputs: Vec<SlotInfo>,
+        outputs: Vec<SlotInfo>,
     }
 
     impl TestNode {
         pub fn new(inputs: usize, outputs: usize) -> Self {
             TestNode {
                 inputs: (0..inputs)
-                    .map(|i| ResourceSlotInfo {
-                        name: format!("in_{}", i).into(),
-                        resource_type: RenderResourceType::Texture,
-                    })
+                    .map(|i| SlotInfo::new(format!("in_{}", i), SlotType::TextureView))
                     .collect(),
                 outputs: (0..outputs)
-                    .map(|i| ResourceSlotInfo {
-                        name: format!("out_{}", i).into(),
-                        resource_type: RenderResourceType::Texture,
-                    })
+                    .map(|i| SlotInfo::new(format!("out_{}", i), SlotType::TextureView))
                     .collect(),
             }
         }
     }
 
     impl Node for TestNode {
-        fn input(&self) -> &[ResourceSlotInfo] {
-            &self.inputs
+        fn input(&self) -> Vec<SlotInfo> {
+            self.inputs.clone()
         }
 
-        fn output(&self) -> &[ResourceSlotInfo] {
-            &self.outputs
+        fn output(&self) -> Vec<SlotInfo> {
+            self.outputs.clone()
         }
 
-        fn update(
-            &mut self,
-            _: &World,
+        fn run(
+            &self,
+            _: &mut RenderGraphContext,
             _: &mut dyn RenderContext,
-            _: &ResourceSlots,
-            _: &mut ResourceSlots,
-        ) {
+            _: &World,
+        ) -> Result<(), NodeRunError> {
+            Ok(())
         }
     }
 
@@ -375,13 +458,13 @@ mod tests {
         }
 
         impl Node for MyNode {
-            fn update(
-                &mut self,
-                _: &World,
+            fn run(
+                &self,
+                _: &mut RenderGraphContext,
                 _: &mut dyn RenderContext,
-                _: &ResourceSlots,
-                _: &mut ResourceSlots,
-            ) {
+                _: &World,
+            ) -> Result<(), NodeRunError> {
+                Ok(())
             }
         }
 

pipelined/bevy_render2/src/render_graph/mod.rs

@@ -1,16 +1,14 @@
+mod context;
 mod edge;
 mod graph;
 mod node;
 mod node_slot;
-mod nodes;
-mod schedule;
 
+pub use context::*;
 pub use edge::*;
 pub use graph::*;
 pub use node::*;
 pub use node_slot::*;
-pub use nodes::*;
-pub use schedule::*;
 
 use thiserror::Error;
 
@@ -18,8 +16,10 @@ use thiserror::Error;
 pub enum RenderGraphError {
     #[error("node does not exist")]
     InvalidNode(NodeLabel),
-    #[error("node slot does not exist")]
-    InvalidNodeSlot(SlotLabel),
+    #[error("output node slot does not exist")]
+    InvalidOutputNodeSlot(SlotLabel),
+    #[error("input node slot does not exist")]
+    InvalidInputNodeSlot(SlotLabel),
     #[error("node does not match the given type")]
     WrongNodeType,
     #[error("attempted to connect a node output slot to an incompatible input node slot")]

pipelined/bevy_render2/src/render_graph/node.rs

@@ -1,9 +1,15 @@
-use super::{Edge, RenderGraphError, ResourceSlotInfo, ResourceSlots};
-use crate::renderer::RenderContext;
+use crate::{
+    render_graph::{
+        Edge, InputSlotError, OutputSlotError, RenderGraphContext, RenderGraphError,
+        RunSubGraphError, SlotInfo, SlotInfos,
+    },
+    renderer::RenderContext,
+};
 use bevy_ecs::world::World;
 use bevy_utils::Uuid;
 use downcast_rs::{impl_downcast, Downcast};
 use std::{borrow::Cow, fmt::Debug};
+use thiserror::Error;
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
 pub struct NodeId(Uuid);
@@ -20,27 +26,38 @@ impl NodeId {
 }
 
 pub trait Node: Downcast + Send + Sync + 'static {
-    fn input(&self) -> &[ResourceSlotInfo] {
-        &[]
+    fn input(&self) -> Vec<SlotInfo> {
+        Vec::new()
     }
 
-    fn output(&self) -> &[ResourceSlotInfo] {
-        &[]
+    fn output(&self) -> Vec<SlotInfo> {
+        Vec::new()
     }
 
-    /// Run the graph node logic. This runs once per graph run after [Node::prepare] has been called
-    /// on all nodes.
-    fn update(
-        &mut self,
-        world: &World,
+    /// Update internal node state using the current render [`World`].
+    fn update(&mut self, _world: &mut World) {}
+
+    /// Run the graph node logic
+    fn run(
+        &self,
+        graph: &mut RenderGraphContext,
         render_context: &mut dyn RenderContext,
-        input: &ResourceSlots,
-        output: &mut ResourceSlots,
-    );
+        world: &World,
+    ) -> Result<(), NodeRunError>;
 }
 
 impl_downcast!(Node);
 
+#[derive(Error, Debug, Eq, PartialEq)]
+pub enum NodeRunError {
+    #[error("encountered an input slot error")]
+    InputSlotError(#[from] InputSlotError),
+    #[error("encountered an output slot error")]
+    OutputSlotError(#[from] OutputSlotError),
+    #[error("encountered an error when running a sub-graph")]
+    RunSubGraphError(#[from] RunSubGraphError),
+}
+
 #[derive(Debug)]
 pub struct Edges {
     pub id: NodeId,
@@ -111,8 +128,8 @@ pub struct NodeState {
     pub name: Option<Cow<'static, str>>,
     pub type_name: &'static str,
     pub node: Box<dyn Node>,
-    pub input_slots: ResourceSlots,
-    pub output_slots: ResourceSlots,
+    pub input_slots: SlotInfos,
+    pub output_slots: SlotInfos,
     pub edges: Edges,
 }
 
@@ -130,8 +147,8 @@ impl NodeState {
         NodeState {
             id,
             name: None,
-            input_slots: ResourceSlots::from(node.input()),
-            output_slots: ResourceSlots::from(node.output()),
+            input_slots: node.input().into(),
+            output_slots: node.output().into(),
             node: Box::new(node),
             type_name: std::any::type_name::<T>(),
             edges: Edges {
@@ -206,3 +223,15 @@ impl From<NodeId> for NodeLabel {
         NodeLabel::Id(value)
     }
 }
+pub struct EmptyNode;
+
+impl Node for EmptyNode {
+    fn run(
+        &self,
+        _graph: &mut RenderGraphContext,
+        _render_context: &mut dyn RenderContext,
+        _world: &World,
+    ) -> Result<(), NodeRunError> {
+        Ok(())
+    }
+}

pipelined/bevy_render2/src/render_graph/node_slot.rs

@@ -1,18 +1,56 @@
-use crate::render_resource::{RenderResourceId, RenderResourceType};
-
-use super::RenderGraphError;
+use crate::render_resource::{BufferId, SamplerId, TextureViewId};
+use bevy_ecs::entity::Entity;
 use std::borrow::Cow;
 
-#[derive(Debug, Clone)]
-pub struct ResourceSlot {
-    pub resource: Option<RenderResourceId>,
-    pub name: Cow<'static, str>,
-    pub resource_type: RenderResourceType,
+#[derive(Debug, Copy, Clone)]
+pub enum SlotValue {
+    Buffer(BufferId),
+    TextureView(TextureViewId),
+    Sampler(SamplerId),
+    Entity(Entity),
 }
 
-#[derive(Default, Debug, Clone)]
-pub struct ResourceSlots {
-    slots: Vec<ResourceSlot>,
+impl SlotValue {
+    pub fn slot_type(self) -> SlotType {
+        match self {
+            SlotValue::Buffer(_) => SlotType::Buffer,
+            SlotValue::TextureView(_) => SlotType::TextureView,
+            SlotValue::Sampler(_) => SlotType::Sampler,
+            SlotValue::Entity(_) => SlotType::Entity,
+        }
+    }
+}
+
+impl From<BufferId> for SlotValue {
+    fn from(value: BufferId) -> Self {
+        SlotValue::Buffer(value)
+    }
+}
+
+impl From<TextureViewId> for SlotValue {
+    fn from(value: TextureViewId) -> Self {
+        SlotValue::TextureView(value)
+    }
+}
+
+impl From<SamplerId> for SlotValue {
+    fn from(value: SamplerId) -> Self {
+        SlotValue::Sampler(value)
+    }
+}
+
+impl From<Entity> for SlotValue {
+    fn from(value: Entity) -> Self {
+        SlotValue::Entity(value)
+    }
+}
+
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub enum SlotType {
+    Buffer,
+    TextureView,
+    Sampler,
+    Entity,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -39,105 +77,83 @@ impl From<&'static str> for SlotLabel {
     }
 }
 
+impl From<Cow<'static, str>> for SlotLabel {
+    fn from(value: Cow<'static, str>) -> Self {
+        SlotLabel::Name(value.clone())
+    }
+}
+
 impl From<usize> for SlotLabel {
     fn from(value: usize) -> Self {
         SlotLabel::Index(value)
     }
 }
 
-impl ResourceSlots {
-    pub fn set(&mut self, label: impl Into<SlotLabel>, resource: RenderResourceId) {
-        let mut slot = self.get_slot_mut(label).unwrap();
-        slot.resource = Some(resource);
+#[derive(Clone, Debug)]
+pub struct SlotInfo {
+    pub name: Cow<'static, str>,
+    pub slot_type: SlotType,
 }
 
-    pub fn get(&self, label: impl Into<SlotLabel>) -> Option<RenderResourceId> {
-        let slot = self.get_slot(label).unwrap();
-        slot.resource.clone()
+impl SlotInfo {
+    pub fn new(name: impl Into<Cow<'static, str>>, slot_type: SlotType) -> Self {
+        SlotInfo {
+            name: name.into(),
+            slot_type,
+        }
+    }
 }
 
-    pub fn get_slot(&self, label: impl Into<SlotLabel>) -> Result<&ResourceSlot, RenderGraphError> {
+#[derive(Default, Debug)]
+pub struct SlotInfos {
+    slots: Vec<SlotInfo>,
+}
+
+impl<T: IntoIterator<Item = SlotInfo>> From<T> for SlotInfos {
+    fn from(slots: T) -> Self {
+        SlotInfos {
+            slots: slots.into_iter().collect(),
+        }
+    }
+}
+
+impl SlotInfos {
+    #[inline]
+    pub fn len(&self) -> usize {
+        self.slots.len()
+    }
+
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.slots.is_empty()
+    }
+
+    pub fn get_slot(&self, label: impl Into<SlotLabel>) -> Option<&SlotInfo> {
         let label = label.into();
         let index = self.get_slot_index(&label)?;
-        self.slots
-            .get(index)
-            .ok_or(RenderGraphError::InvalidNodeSlot(label))
+        self.slots.get(index)
     }
 
-    pub fn get_slot_mut(
-        &mut self,
-        label: impl Into<SlotLabel>,
-    ) -> Result<&mut ResourceSlot, RenderGraphError> {
+    pub fn get_slot_mut(&mut self, label: impl Into<SlotLabel>) -> Option<&mut SlotInfo> {
         let label = label.into();
         let index = self.get_slot_index(&label)?;
-        self.slots
-            .get_mut(index)
-            .ok_or(RenderGraphError::InvalidNodeSlot(label))
+        self.slots.get_mut(index)
     }
 
-    pub fn get_slot_index(&self, label: impl Into<SlotLabel>) -> Result<usize, RenderGraphError> {
+    pub fn get_slot_index(&self, label: impl Into<SlotLabel>) -> Option<usize> {
         let label = label.into();
         match label {
-            SlotLabel::Index(index) => Ok(index),
+            SlotLabel::Index(index) => Some(index),
             SlotLabel::Name(ref name) => self
                 .slots
                 .iter()
                 .enumerate()
                 .find(|(_i, s)| s.name == *name)
-                .map(|(i, _s)| i)
-                .ok_or(RenderGraphError::InvalidNodeSlot(label)),
+                .map(|(i, _s)| i),
         }
     }
 
-    pub fn iter(&self) -> impl Iterator<Item = &ResourceSlot> {
+    pub fn iter(&self) -> impl Iterator<Item = &SlotInfo> {
         self.slots.iter()
     }
-
-    pub fn iter_mut(&mut self) -> impl Iterator<Item = &mut ResourceSlot> {
-        self.slots.iter_mut()
-    }
-
-    pub fn len(&self) -> usize {
-        self.slots.len()
-    }
-
-    pub fn is_empty(&self) -> bool {
-        self.slots.is_empty()
-    }
-}
-
-impl From<&ResourceSlotInfo> for ResourceSlot {
-    fn from(slot: &ResourceSlotInfo) -> Self {
-        ResourceSlot {
-            resource: None,
-            name: slot.name.clone(),
-            resource_type: slot.resource_type.clone(),
-        }
-    }
-}
-
-impl From<&[ResourceSlotInfo]> for ResourceSlots {
-    fn from(slots: &[ResourceSlotInfo]) -> Self {
-        ResourceSlots {
-            slots: slots
-                .iter()
-                .map(|s| s.into())
-                .collect::<Vec<ResourceSlot>>(),
-        }
-    }
-}
-
-#[derive(Clone, Debug)]
-pub struct ResourceSlotInfo {
-    pub name: Cow<'static, str>,
-    pub resource_type: RenderResourceType,
-}
-
-impl ResourceSlotInfo {
-    pub fn new(name: impl Into<Cow<'static, str>>, resource_type: RenderResourceType) -> Self {
-        ResourceSlotInfo {
-            name: name.into(),
-            resource_type,
-        }
-    }
 }

pipelined/bevy_render2/src/render_graph/nodes/mod.rs

@@ -1,3 +0,0 @@
-mod window_swap_chain_node;
-
-pub use window_swap_chain_node::*;

pipelined/bevy_render2/src/render_graph/nodes/window_swap_chain_node.rs

@@ -1,99 +0,0 @@
-use crate::{
-    render_graph::{Node, ResourceSlotInfo, ResourceSlots},
-    render_resource::{RenderResourceId, RenderResourceType, SwapChainDescriptor},
-    renderer::RenderContext,
-};
-use bevy_ecs::world::World;
-use bevy_utils::HashMap;
-use bevy_window::WindowId;
-use raw_window_handle::{HasRawWindowHandle, RawWindowHandle};
-use std::borrow::Cow;
-use std::ops::{Deref, DerefMut};
-
-pub struct ExtractedWindow {
-    pub id: WindowId,
-    pub handle: RawWindowHandleWrapper,
-    pub physical_width: u32,
-    pub physical_height: u32,
-    pub vsync: bool,
-}
-
-#[derive(Default)]
-pub struct ExtractedWindows {
-    pub windows: HashMap<WindowId, ExtractedWindow>,
-}
-
-impl Deref for ExtractedWindows {
-    type Target = HashMap<WindowId, ExtractedWindow>;
-
-    fn deref(&self) -> &Self::Target {
-        &self.windows
-    }
-}
-
-impl DerefMut for ExtractedWindows {
-    fn deref_mut(&mut self) -> &mut Self::Target {
-        &mut self.windows
-    }
-}
-
-pub struct RawWindowHandleWrapper(pub RawWindowHandle);
-
-// TODO: THIS IS NOT SAFE ... ONLY FOR PROTOTYPING
-unsafe impl Send for RawWindowHandleWrapper {}
-unsafe impl Sync for RawWindowHandleWrapper {}
-
-// TODO: safe?
-unsafe impl HasRawWindowHandle for RawWindowHandleWrapper {
-    fn raw_window_handle(&self) -> RawWindowHandle {
-        self.0.clone()
-    }
-}
-
-pub struct WindowSwapChainNode {
-    window_id: WindowId,
-}
-
-impl WindowSwapChainNode {
-    pub const OUT_TEXTURE: &'static str = "texture";
-
-    pub fn new(window_id: WindowId) -> Self {
-        WindowSwapChainNode { window_id }
-    }
-}
-
-impl Node for WindowSwapChainNode {
-    fn output(&self) -> &[ResourceSlotInfo] {
-        static OUTPUT: &[ResourceSlotInfo] = &[ResourceSlotInfo {
-            name: Cow::Borrowed(WindowSwapChainNode::OUT_TEXTURE),
-            resource_type: RenderResourceType::Texture,
-        }];
-        OUTPUT
-    }
-
-    fn update(
-        &mut self,
-        world: &World,
-        render_context: &mut dyn RenderContext,
-        _input: &ResourceSlots,
-        output: &mut ResourceSlots,
-    ) {
-        let windows = world.get_resource::<ExtractedWindows>().unwrap();
-        let window = windows
-            .get(&self.window_id)
-            .expect("Window swapchain node refers to a non-existent window.");
-
-        let render_resource_context = render_context.resources_mut();
-        let swap_chain_descriptor = SwapChainDescriptor {
-            window_id: window.id,
-            format: crate::texture::TextureFormat::Bgra8UnormSrgb,
-            width: window.physical_width,
-            height: window.physical_height,
-            vsync: window.vsync,
-        };
-
-        let swap_chain_texture =
-            render_resource_context.next_swap_chain_texture(&swap_chain_descriptor);
-        output.set(0, RenderResourceId::Texture(swap_chain_texture));
-    }
-}

pipelined/bevy_render2/src/render_graph/schedule.rs

@@ -1,552 +0,0 @@
-use super::{NodeId, NodeState, RenderGraph, RenderGraphError};
-use bevy_utils::HashMap;
-use thiserror::Error;
-
-#[derive(Error, Debug)]
-pub enum StagerError {
-    // This might have to be `:` tagged at the end.
-    #[error("encountered a `RenderGraphError`")]
-    RenderGraphError(#[from] RenderGraphError),
-}
-
-#[derive(Default, Debug, Eq, PartialEq)]
-pub struct Stage {
-    pub jobs: Vec<OrderedJob>,
-}
-
-#[derive(Default, Debug, Eq, PartialEq)]
-pub struct OrderedJob {
-    pub nodes: Vec<NodeId>,
-}
-
-#[derive(Default, Debug)]
-pub struct StageBorrow<'a> {
-    pub jobs: Vec<OrderedJobBorrow<'a>>,
-}
-
-#[derive(Default, Debug)]
-pub struct OrderedJobBorrow<'a> {
-    pub node_states: Vec<&'a mut NodeState>,
-}
-
-#[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd)]
-struct NodeIndices {
-    stage: usize,
-    job: usize,
-    node: usize,
-}
-
-#[derive(Default, Debug)]
-pub struct Stages {
-    stages: Vec<Stage>,
-    /// a collection of node indices that are used to efficiently borrow render graph nodes
-    node_indices: HashMap<NodeId, NodeIndices>,
-}
-
-impl Stages {
-    pub fn new(stages: Vec<Stage>) -> Self {
-        let mut node_indices = HashMap::default();
-        for (stage_index, stage) in stages.iter().enumerate() {
-            for (job_index, job) in stage.jobs.iter().enumerate() {
-                for (node_index, node) in job.nodes.iter().enumerate() {
-                    node_indices.insert(
-                        *node,
-                        NodeIndices {
-                            stage: stage_index,
-                            job: job_index,
-                            node: node_index,
-                        },
-                    );
-                }
-            }
-        }
-        Stages {
-            stages,
-            node_indices,
-        }
-    }
-
-    pub fn borrow<'a>(&self, render_graph: &'a mut RenderGraph) -> Vec<StageBorrow<'a>> {
-        // unfortunately borrowing render graph nodes in a specific order takes a little bit of
-        // gymnastics
-        let mut stage_borrows = Vec::with_capacity(self.stages.len());
-
-        let mut node_borrows = Vec::new();
-        for node in render_graph.iter_nodes_mut() {
-            let indices = self.node_indices.get(&node.id).unwrap();
-            node_borrows.push((node, indices));
-        }
-
-        node_borrows.sort_by_key(|(_node, indices)| <&NodeIndices>::clone(indices));
-        let mut last_stage = usize::MAX;
-        let mut last_job = usize::MAX;
-        for (node, indices) in node_borrows.drain(..) {
-            if last_stage != indices.stage {
-                stage_borrows.push(StageBorrow::default());
-                last_job = usize::MAX;
-            }
-
-            let stage = &mut stage_borrows[indices.stage];
-            if last_job != indices.job {
-                stage.jobs.push(OrderedJobBorrow::default());
-            }
-
-            let job = &mut stage.jobs[indices.job];
-            job.node_states.push(node);
-
-            last_stage = indices.stage;
-            last_job = indices.job;
-        }
-
-        stage_borrows
-    }
-}
-
-/// Produces a collection of `Stages`, which are sets of OrderedJobs that must be run before moving
-/// on to the next stage
-pub trait RenderGraphStager {
-    fn get_stages(&mut self, render_graph: &RenderGraph) -> Result<Stages, RenderGraphError>;
-}
-
-// TODO: remove this
-/// This scheduler ignores dependencies and puts everything in one stage. It shouldn't be used for
-/// anything :)
-#[derive(Debug, Default)]
-pub struct LinearStager;
-
-impl RenderGraphStager for LinearStager {
-    fn get_stages(&mut self, render_graph: &RenderGraph) -> Result<Stages, RenderGraphError> {
-        let mut stage = Stage::default();
-        let mut job = OrderedJob::default();
-        for node in render_graph.iter_nodes() {
-            job.nodes.push(node.id);
-        }
-
-        stage.jobs.push(job);
-
-        Ok(Stages::new(vec![stage]))
-    }
-}
-
-#[derive(Debug, Copy, Clone)]
-/// Determines the grouping strategy used when constructing graph stages
-pub enum JobGrouping {
-    /// Default to adding the current node to a new job in its assigned stage. This results
-    /// in a "loose" pack that is easier to parallelize but has more jobs
-    Loose,
-    /// Default to adding the current node into the first job in its assigned stage. This results
-    /// in a "tight" pack that is harder to parallelize but results in fewer jobs
-    Tight,
-}
-
-#[derive(Debug)]
-/// Produces Render Graph stages and jobs in a way that ensures node dependencies are respected.
-pub struct DependentNodeStager {
-    job_grouping: JobGrouping,
-}
-
-impl DependentNodeStager {
-    pub fn loose_grouping() -> Self {
-        DependentNodeStager {
-            job_grouping: JobGrouping::Loose,
-        }
-    }
-
-    pub fn tight_grouping() -> Self {
-        DependentNodeStager {
-            job_grouping: JobGrouping::Tight,
-        }
-    }
-}
-
-impl RenderGraphStager for DependentNodeStager {
-    fn get_stages<'a>(&mut self, render_graph: &RenderGraph) -> Result<Stages, RenderGraphError> {
-        // get all nodes without input. this intentionally includes nodes with no outputs
-        let output_only_nodes = render_graph
-            .iter_nodes()
-            .filter(|node| node.input_slots.is_empty());
-        let mut stages = vec![Stage::default()];
-        let mut node_stages = HashMap::default();
-        for output_only_node in output_only_nodes {
-            // each "output only" node should start a new job on the first stage
-            stage_node(
-                render_graph,
-                &mut stages,
-                &mut node_stages,
-                output_only_node,
-                self.job_grouping,
-            );
-        }
-
-        Ok(Stages::new(stages))
-    }
-}
-
-fn stage_node(
-    graph: &RenderGraph,
-    stages: &mut Vec<Stage>,
-    node_stages_and_jobs: &mut HashMap<NodeId, (usize, usize)>,
-    node: &NodeState,
-    job_grouping: JobGrouping,
-) {
-    // don't re-visit nodes or visit them before all of their parents have been visited
-    if node_stages_and_jobs.contains_key(&node.id)
-        || node
-            .edges
-            .input_edges
-            .iter()
-            .any(|e| !node_stages_and_jobs.contains_key(&e.get_output_node()))
-    {
-        return;
-    }
-
-    // by default assume we are creating a new job on a new stage
-    let mut stage_index = 0;
-    let mut job_index = match job_grouping {
-        JobGrouping::Tight => Some(0),
-        JobGrouping::Loose => None,
-    };
-
-    // check to see if the current node has a parent. if so, grab the parent with the highest stage
-    if let Some((max_parent_stage, max_parent_job)) = node
-        .edges
-        .input_edges
-        .iter()
-        .map(|e| {
-            node_stages_and_jobs
-                .get(&e.get_output_node())
-                .expect("Already checked that parents were visited.")
-        })
-        .max()
-    {
-        // count the number of parents that are in the highest stage
-        let max_stage_parent_count = node
-            .edges
-            .input_edges
-            .iter()
-            .filter(|e| {
-                let (max_stage, _) = node_stages_and_jobs
-                    .get(&e.get_output_node())
-                    .expect("Already checked that parents were visited.");
-                max_stage == max_parent_stage
-            })
-            .count();
-
-        // if the current node has more than one parent on the highest stage (aka requires
-        // synchronization), then move it to the next stage and start a new job on that
-        // stage
-        if max_stage_parent_count > 1 {
-            stage_index = max_parent_stage + 1;
-        } else {
-            stage_index = *max_parent_stage;
-            job_index = Some(*max_parent_job);
-        }
-    }
-
-    if stage_index == stages.len() {
-        stages.push(Stage::default());
-    }
-
-    let stage = &mut stages[stage_index];
-
-    let job_index = job_index.unwrap_or_else(|| stage.jobs.len());
-    if job_index == stage.jobs.len() {
-        stage.jobs.push(OrderedJob::default());
-    }
-
-    let job = &mut stage.jobs[job_index];
-    job.nodes.push(node.id);
-
-    node_stages_and_jobs.insert(node.id, (stage_index, job_index));
-
-    for (_edge, node) in graph.iter_node_outputs(node.id).unwrap() {
-        stage_node(graph, stages, node_stages_and_jobs, node, job_grouping);
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use crate::renderer::RenderContext;
-    use crate::{
-        render_graph::{
-            DependentNodeStager, Node, NodeId, OrderedJob, RenderGraph, RenderGraphStager,
-            ResourceSlotInfo, ResourceSlots, Stage,
-        },
-        render_resource::RenderResourceType,
-    };
-    use bevy_ecs::world::World;
-
-    struct TestNode {
-        inputs: Vec<ResourceSlotInfo>,
-        outputs: Vec<ResourceSlotInfo>,
-    }
-
-    impl TestNode {
-        pub fn new(inputs: usize, outputs: usize) -> Self {
-            TestNode {
-                inputs: (0..inputs)
-                    .map(|i| ResourceSlotInfo {
-                        name: format!("in_{}", i).into(),
-                        resource_type: RenderResourceType::Texture,
-                    })
-                    .collect(),
-                outputs: (0..outputs)
-                    .map(|i| ResourceSlotInfo {
-                        name: format!("out_{}", i).into(),
-                        resource_type: RenderResourceType::Texture,
-                    })
-                    .collect(),
-            }
-        }
-    }
-
-    impl Node for TestNode {
-        fn input(&self) -> &[ResourceSlotInfo] {
-            &self.inputs
-        }
-
-        fn output(&self) -> &[ResourceSlotInfo] {
-            &self.outputs
-        }
-
-        fn update(
-            &mut self,
-            _: &World,
-            _: &mut dyn RenderContext,
-            _: &ResourceSlots,
-            _: &mut ResourceSlots,
-        ) {
-        }
-    }
-
-    #[test]
-    fn test_render_graph_dependency_stager_loose() {
-        let mut graph = RenderGraph::default();
-
-        // Setup graph to look like this:
-        //
-        // A -> B -> C -> D
-        //    /     /
-        //  E      F -> G
-        //
-        // H -> I -> J
-
-        let a_id = graph.add_node("A", TestNode::new(0, 1));
-        let b_id = graph.add_node("B", TestNode::new(2, 1));
-        let c_id = graph.add_node("C", TestNode::new(2, 1));
-        let d_id = graph.add_node("D", TestNode::new(1, 0));
-        let e_id = graph.add_node("E", TestNode::new(0, 1));
-        let f_id = graph.add_node("F", TestNode::new(0, 2));
-        let g_id = graph.add_node("G", TestNode::new(1, 0));
-        let h_id = graph.add_node("H", TestNode::new(0, 1));
-        let i_id = graph.add_node("I", TestNode::new(1, 1));
-        let j_id = graph.add_node("J", TestNode::new(1, 0));
-
-        graph.add_node_edge("A", "B").unwrap();
-        graph.add_node_edge("B", "C").unwrap();
-        graph.add_node_edge("C", "D").unwrap();
-        graph.add_node_edge("E", "B").unwrap();
-        graph.add_node_edge("F", "C").unwrap();
-        graph.add_node_edge("F", "G").unwrap();
-        graph.add_node_edge("H", "I").unwrap();
-        graph.add_node_edge("I", "J").unwrap();
-
-        let mut stager = DependentNodeStager::loose_grouping();
-        let mut stages = stager.get_stages(&graph).unwrap();
-
-        // Expected Stages:
-        // (X indicates nodes that are not part of that stage)
-
-        // Stage 1
-        // A -> X -> X -> X
-        //    /     /
-        //  E      F -> G
-        //
-        // H -> I -> J
-
-        // Stage 2
-        // X -> B -> C -> D
-        //    /     /
-        //  X      X -> X
-        //
-        // X -> X -> X
-
-        let mut expected_stages = vec![
-            Stage {
-                jobs: vec![
-                    OrderedJob {
-                        nodes: vec![f_id, g_id],
-                    },
-                    OrderedJob { nodes: vec![a_id] },
-                    OrderedJob { nodes: vec![e_id] },
-                    OrderedJob {
-                        nodes: vec![h_id, i_id, j_id],
-                    },
-                ],
-            },
-            Stage {
-                jobs: vec![OrderedJob {
-                    nodes: vec![b_id, c_id, d_id],
-                }],
-            },
-        ];
-
-        // ensure job order lines up within stages (this can vary due to hash maps)
-        // jobs within a stage are unordered conceptually so this is ok
-        expected_stages
-            .iter_mut()
-            .for_each(|stage| stage.jobs.sort_by_key(|job| job.nodes[0]));
-
-        stages
-            .stages
-            .iter_mut()
-            .for_each(|stage| stage.jobs.sort_by_key(|job| job.nodes[0]));
-
-        assert_eq!(
-            stages.stages, expected_stages,
-            "stages should be loosely grouped"
-        );
-
-        let mut borrowed = stages.borrow(&mut graph);
-        // ensure job order lines up within stages (this can vary due to hash maps)
-        // jobs within a stage are unordered conceptually so this is ok
-        borrowed
-            .iter_mut()
-            .for_each(|stage| stage.jobs.sort_by_key(|job| job.node_states[0].id));
-
-        assert_eq!(
-            borrowed.len(),
-            expected_stages.len(),
-            "same number of stages"
-        );
-        for (stage_index, borrowed_stage) in borrowed.iter().enumerate() {
-            assert_eq!(
-                borrowed_stage.jobs.len(),
-                stages.stages[stage_index].jobs.len(),
-                "job length matches"
-            );
-            for (job_index, borrowed_job) in borrowed_stage.jobs.iter().enumerate() {
-                assert_eq!(
-                    borrowed_job.node_states.len(),
-                    stages.stages[stage_index].jobs[job_index].nodes.len(),
-                    "node length matches"
-                );
-                for (node_index, borrowed_node) in borrowed_job.node_states.iter().enumerate() {
-                    assert_eq!(
-                        borrowed_node.id,
-                        stages.stages[stage_index].jobs[job_index].nodes[node_index]
-                    );
-                }
-            }
-        }
-    }
-
-    #[test]
-    fn test_render_graph_dependency_stager_tight() {
-        let mut graph = RenderGraph::default();
-
-        // Setup graph to look like this:
-        //
-        // A -> B -> C -> D
-        //    /     /
-        //  E      F -> G
-        //
-        // H -> I -> J
-
-        let _a_id = graph.add_node("A", TestNode::new(0, 1));
-        let b_id = graph.add_node("B", TestNode::new(2, 1));
-        let c_id = graph.add_node("C", TestNode::new(2, 1));
-        let d_id = graph.add_node("D", TestNode::new(1, 0));
-        let _e_id = graph.add_node("E", TestNode::new(0, 1));
-        let f_id = graph.add_node("F", TestNode::new(0, 2));
-        let g_id = graph.add_node("G", TestNode::new(1, 0));
-        let h_id = graph.add_node("H", TestNode::new(0, 1));
-        let i_id = graph.add_node("I", TestNode::new(1, 1));
-        let j_id = graph.add_node("J", TestNode::new(1, 0));
-
-        graph.add_node_edge("A", "B").unwrap();
-        graph.add_node_edge("B", "C").unwrap();
-        graph.add_node_edge("C", "D").unwrap();
-        graph.add_node_edge("E", "B").unwrap();
-        graph.add_node_edge("F", "C").unwrap();
-        graph.add_node_edge("F", "G").unwrap();
-        graph.add_node_edge("H", "I").unwrap();
-        graph.add_node_edge("I", "J").unwrap();
-
-        let mut stager = DependentNodeStager::tight_grouping();
-        let mut stages = stager.get_stages(&graph).unwrap();
-
-        // Expected Stages:
-        // (X indicates nodes that are not part of that stage)
-
-        // Stage 1
-        // A -> X -> X -> X
-        //    /     /
-        //  E      F -> G
-        //
-        // H -> I -> J
-
-        // Stage 2
-        // X -> B -> C -> D
-        //    /     /
-        //  X      X -> X
-        //
-        // X -> X -> X
-
-        assert_eq!(stages.stages[0].jobs.len(), 1, "expect exactly 1 job");
-
-        let job = &stages.stages[0].jobs[0];
-
-        assert_eq!(job.nodes.len(), 7, "expect exactly 7 nodes in the job");
-
-        // its hard to test the exact order of this job's nodes because of hashing, so instead we'll
-        // test the constraints that must hold true
-        let index =
-            |node_id: NodeId| -> usize { job.nodes.iter().position(|id| *id == node_id).unwrap() };
-
-        assert!(index(f_id) < index(g_id));
-        assert!(index(h_id) < index(i_id));
-        assert!(index(i_id) < index(j_id));
-
-        let expected_stage_1 = Stage {
-            jobs: vec![OrderedJob {
-                nodes: vec![b_id, c_id, d_id],
-            }],
-        };
-
-        assert_eq!(stages.stages[1], expected_stage_1,);
-
-        let mut borrowed = stages.borrow(&mut graph);
-        // ensure job order lines up within stages (this can vary due to hash maps)
-        // jobs within a stage are unordered conceptually so this is ok
-        stages
-            .stages
-            .iter_mut()
-            .for_each(|stage| stage.jobs.sort_by_key(|job| job.nodes[0]));
-        borrowed
-            .iter_mut()
-            .for_each(|stage| stage.jobs.sort_by_key(|job| job.node_states[0].id));
-
-        assert_eq!(borrowed.len(), 2, "same number of stages");
-        for (stage_index, borrowed_stage) in borrowed.iter().enumerate() {
-            assert_eq!(
-                borrowed_stage.jobs.len(),
-                stages.stages[stage_index].jobs.len(),
-                "job length matches"
-            );
-            for (job_index, borrowed_job) in borrowed_stage.jobs.iter().enumerate() {
-                assert_eq!(
-                    borrowed_job.node_states.len(),
-                    stages.stages[stage_index].jobs[job_index].nodes.len(),
-                    "node length matches"
-                );
-                for (node_index, borrowed_node) in borrowed_job.node_states.iter().enumerate() {
-                    assert_eq!(
-                        borrowed_node.id,
-                        stages.stages[stage_index].jobs[job_index].nodes[node_index]
-                    );
-                }
-            }
-        }
-    }
-}

pipelined/bevy_render2/src/render_phase/draw.rs

@@ -0,0 +1,59 @@
+use crate::render_phase::TrackedRenderPass;
+use bevy_ecs::{entity::Entity, world::World};
+use bevy_utils::HashMap;
+use parking_lot::{RwLock, RwLockReadGuard, RwLockWriteGuard};
+use std::{any::TypeId, fmt::Debug, hash::Hash};
+
+// TODO: should this be generic on "drawn thing"? would provide more flexibility and  explicitness
+// instead of hard coded draw key and sort key
+pub trait Draw: Send + Sync + 'static {
+    fn draw(
+        &mut self,
+        world: &World,
+        pass: &mut TrackedRenderPass,
+        view: Entity,
+        draw_key: usize,
+        sort_key: usize,
+    );
+}
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub struct DrawFunctionId(usize);
+
+#[derive(Default)]
+pub struct DrawFunctionsInternal {
+    pub draw_functions: Vec<Box<dyn Draw>>,
+    pub indices: HashMap<TypeId, DrawFunctionId>,
+}
+
+impl DrawFunctionsInternal {
+    pub fn add<D: Draw>(&mut self, draw_function: D) -> DrawFunctionId {
+        self.draw_functions.push(Box::new(draw_function));
+        let id = DrawFunctionId(self.draw_functions.len() - 1);
+        self.indices.insert(TypeId::of::<D>(), id);
+        id
+    }
+
+    pub fn get_mut(&mut self, id: DrawFunctionId) -> Option<&mut dyn Draw> {
+        self.draw_functions.get_mut(id.0).map(|f| &mut **f)
+    }
+
+    pub fn get_id<D: Draw>(&self) -> Option<DrawFunctionId> {
+        self.indices.get(&TypeId::of::<D>()).copied()
+    }
+}
+
+#[derive(Default)]
+pub struct DrawFunctions {
+    internal: RwLock<DrawFunctionsInternal>,
+}
+
+impl DrawFunctions {
+    pub fn read(&self) -> RwLockReadGuard<'_, DrawFunctionsInternal> {
+        self.internal.read()
+    }
+
+    pub fn write(&self) -> RwLockWriteGuard<'_, DrawFunctionsInternal> {
+        self.internal.write()
+    }
+}

pipelined/bevy_render2/src/render_phase/draw_state.rs

@@ -1,3 +1,5 @@
+use bevy_utils::tracing::debug;
+
 use crate::{
     pass::RenderPass,
     pipeline::{BindGroupDescriptorId, IndexFormat, PipelineId},
@@ -102,6 +104,7 @@ impl<'a> TrackedRenderPass<'a> {
         }
     }
     pub fn set_pipeline(&mut self, pipeline: PipelineId) {
+        debug!("set pipeline: {:?}", pipeline);
         if self.state.is_pipeline_set(pipeline) {
             return;
         }
@@ -120,7 +123,16 @@ impl<'a> TrackedRenderPass<'a> {
             .state
             .is_bind_group_set(index as usize, bind_group, dynamic_uniform_indices)
         {
+            debug!(
+                "set bind_group {} (already set): {:?} ({:?})",
+                index, bind_group, dynamic_uniform_indices
+            );
             return;
+        } else {
+            debug!(
+                "set bind_group {}: {:?} ({:?})",
+                index, bind_group, dynamic_uniform_indices
+            );
         }
         self.pass.set_bind_group(
             index as u32,
@@ -134,7 +146,13 @@ impl<'a> TrackedRenderPass<'a> {
 
     pub fn set_vertex_buffer(&mut self, index: usize, buffer: BufferId, offset: u64) {
         if self.state.is_vertex_buffer_set(index, buffer, offset) {
+            debug!(
+                "set vertex buffer {} (already set): {:?} ({})",
+                index, buffer, offset
+            );
             return;
+        } else {
+            debug!("set vertex buffer {}: {:?} ({})", index, buffer, offset);
         }
         self.pass.set_vertex_buffer(index as u32, buffer, offset);
         self.state.set_vertex_buffer(index, buffer, offset);
@@ -142,13 +160,20 @@ impl<'a> TrackedRenderPass<'a> {
 
     pub fn set_index_buffer(&mut self, buffer: BufferId, offset: u64, index_format: IndexFormat) {
         if self.state.is_index_buffer_set(buffer, offset, index_format) {
+            debug!("set index buffer (already set): {:?} ({})", buffer, offset);
             return;
+        } else {
+            debug!("set index buffer: {:?} ({})", buffer, offset);
         }
         self.pass.set_index_buffer(buffer, offset, index_format);
         self.state.set_index_buffer(buffer, offset, index_format);
     }
 
     pub fn draw_indexed(&mut self, indices: Range<u32>, base_vertex: i32, instances: Range<u32>) {
+        debug!(
+            "draw indexed: {:?} {} {:?}",
+            indices, base_vertex, instances
+        );
         self.pass.draw_indexed(indices, base_vertex, instances);
     }
 }

pipelined/bevy_render2/src/render_phase/mod.rs

@@ -0,0 +1,47 @@
+mod draw;
+mod draw_state;
+
+pub use draw::*;
+pub use draw_state::*;
+
+use std::marker::PhantomData;
+use bevy_ecs::prelude::Query;
+
+// TODO: make this configurable per phase?
+pub struct Drawable {
+    pub draw_function: DrawFunctionId,
+    pub draw_key: usize,
+    pub sort_key: usize,
+}
+
+pub struct RenderPhase<T> {
+    pub drawn_things: Vec<Drawable>,
+    marker: PhantomData<fn() -> T>,
+}
+
+impl<T> Default for RenderPhase<T> {
+    fn default() -> Self {
+        Self {
+            drawn_things: Vec::new(),
+            marker: PhantomData,
+        }
+    }
+}
+
+impl<T> RenderPhase<T> {
+    #[inline]
+    pub fn add(&mut self, drawable: Drawable) {
+        self.drawn_things.push(drawable);
+    }
+
+    pub fn sort(&mut self) {
+        self.drawn_things.sort_by_key(|d| d.sort_key);
+    }
+}
+
+
+pub fn sort_phase_system<T: 'static>(mut render_phases: Query<&mut RenderPhase<T>>) {
+   for mut phase in render_phases.iter_mut() {
+       phase.sort();
+   } 
+}

pipelined/bevy_render2/src/render_resource/bind_group.rs

@@ -1,6 +1,6 @@
-use crate::render_resource::RenderResourceId;
-
-use super::{BufferId, RenderResourceBinding, SamplerId, TextureId};
+use crate::render_resource::{
+    BufferId, RenderResourceBinding, RenderResourceId, SamplerId, TextureViewId,
+};
 use bevy_utils::AHasher;
 use std::{
     hash::{Hash, Hasher},
@@ -21,7 +21,6 @@ pub struct IndexedBindGroupEntry {
 pub struct BindGroup {
     pub id: BindGroupId,
     pub indexed_bindings: Arc<[IndexedBindGroupEntry]>,
-    pub dynamic_uniform_indices: Option<Arc<[u32]>>,
 }
 
 impl BindGroup {
@@ -33,21 +32,12 @@ impl BindGroup {
 #[derive(Debug, Default)]
 pub struct BindGroupBuilder {
     pub indexed_bindings: Vec<IndexedBindGroupEntry>,
-    pub dynamic_uniform_indices: Vec<u32>,
     pub hasher: AHasher,
 }
 
 impl BindGroupBuilder {
     pub fn add_binding<T: Into<RenderResourceBinding>>(mut self, index: u32, binding: T) -> Self {
         let binding = binding.into();
-        if let RenderResourceBinding::Buffer {
-            dynamic_index: Some(dynamic_index),
-            ..
-        } = binding
-        {
-            self.dynamic_uniform_indices.push(dynamic_index);
-        }
-
         self.hash_binding(&binding);
         self.indexed_bindings.push(IndexedBindGroupEntry {
             index,
@@ -56,8 +46,8 @@ impl BindGroupBuilder {
         self
     }
 
-    pub fn add_texture(self, index: u32, texture: TextureId) -> Self {
-        self.add_binding(index, RenderResourceBinding::Texture(texture))
+    pub fn add_texture_view(self, index: u32, texture: TextureViewId) -> Self {
+        self.add_binding(index, RenderResourceBinding::TextureView(texture))
     }
 
     pub fn add_sampler(self, index: u32, sampler: SamplerId) -> Self {
@@ -70,24 +60,6 @@ impl BindGroupBuilder {
             RenderResourceBinding::Buffer {
                 buffer,
                 range,
-                dynamic_index: None,
-            },
-        )
-    }
-
-    pub fn add_dynamic_buffer(
-        self,
-        index: u32,
-        buffer: BufferId,
-        range: Range<u64>,
-        dynamic_index: u32,
-    ) -> Self {
-        self.add_binding(
-            index,
-            RenderResourceBinding::Buffer {
-                buffer,
-                range,
-                dynamic_index: Some(dynamic_index),
             },
         )
     }
@@ -98,11 +70,6 @@ impl BindGroupBuilder {
         BindGroup {
             id: BindGroupId(self.hasher.finish()),
             indexed_bindings: self.indexed_bindings.into(),
-            dynamic_uniform_indices: if self.dynamic_uniform_indices.is_empty() {
-                None
-            } else {
-                Some(self.dynamic_uniform_indices.into())
-            },
         }
     }
 
@@ -111,13 +78,12 @@ impl BindGroupBuilder {
             RenderResourceBinding::Buffer {
                 buffer,
                 range,
-                dynamic_index: _, // dynamic_index is not a part of the binding
             } => {
                 RenderResourceId::Buffer(*buffer).hash(&mut self.hasher);
                 range.hash(&mut self.hasher);
             }
-            RenderResourceBinding::Texture(texture) => {
-                RenderResourceId::Texture(*texture).hash(&mut self.hasher);
+            RenderResourceBinding::TextureView(texture) => {
+                RenderResourceId::TextureView(*texture).hash(&mut self.hasher);
             }
             RenderResourceBinding::Sampler(sampler) => {
                 RenderResourceId::Sampler(*sampler).hash(&mut self.hasher);

pipelined/bevy_render2/src/render_resource/buffer_vec.rs

@@ -106,7 +106,7 @@ impl<T: Pod> BufferVec<T> {
             render_resources.unmap_buffer(staging_buffer);
         }
     }
-    pub fn write_to_uniform_buffer(&self, render_context: &mut dyn RenderContext) {
+    pub fn write_to_buffer(&self, render_context: &mut dyn RenderContext) {
         if let (Some(staging_buffer), Some(uniform_buffer)) = (self.staging_buffer, self.buffer) {
             render_context.copy_buffer_to_buffer(
                 staging_buffer,

pipelined/bevy_render2/src/render_resource/render_resource_bindings.rs

@@ -1,4 +1,4 @@
-use super::{BufferId, SamplerId, TextureId};
+use crate::render_resource::{BufferId, SamplerId, TextureViewId};
 use std::ops::Range;
 
 #[derive(Clone, PartialEq, Eq, Debug)]
@@ -6,15 +6,14 @@ pub enum RenderResourceBinding {
     Buffer {
         buffer: BufferId,
         range: Range<u64>,
-        dynamic_index: Option<u32>,
     },
-    Texture(TextureId),
+    TextureView(TextureViewId),
     Sampler(SamplerId),
 }
 
 impl RenderResourceBinding {
-    pub fn get_texture(&self) -> Option<TextureId> {
-        if let RenderResourceBinding::Texture(texture) = self {
+    pub fn get_texture_view(&self) -> Option<TextureViewId> {
+        if let RenderResourceBinding::TextureView(texture) = self {
             Some(*texture)
         } else {
             None
@@ -29,16 +28,6 @@ impl RenderResourceBinding {
         }
     }
 
-    pub fn is_dynamic_buffer(&self) -> bool {
-        matches!(
-            self,
-            RenderResourceBinding::Buffer {
-                dynamic_index: Some(_),
-                ..
-            }
-        )
-    }
-
     pub fn get_sampler(&self) -> Option<SamplerId> {
         if let RenderResourceBinding::Sampler(sampler) = self {
             Some(*sampler)
@@ -48,9 +37,9 @@ impl RenderResourceBinding {
     }
 }
 
-impl From<TextureId> for RenderResourceBinding {
-    fn from(id: TextureId) -> Self {
-        RenderResourceBinding::Texture(id)
+impl From<TextureViewId> for RenderResourceBinding {
+    fn from(id: TextureViewId) -> Self {
+        RenderResourceBinding::TextureView(id)
     }
 }
 

pipelined/bevy_render2/src/render_resource/render_resource_id.rs

@@ -1,22 +1,15 @@
-use crate::render_resource::{BufferId, SamplerId, TextureId};
-
-#[derive(Debug, Clone, Eq, PartialEq)]
-pub enum RenderResourceType {
-    Buffer,
-    Texture,
-    Sampler,
-}
+use crate::render_resource::{BufferId, SamplerId, TextureViewId};
 
 #[derive(Debug, Clone, Hash, Eq, PartialEq)]
 pub enum RenderResourceId {
     Buffer(BufferId),
-    Texture(TextureId),
+    TextureView(TextureViewId),
     Sampler(SamplerId),
 }
 
 impl RenderResourceId {
-    pub fn get_texture(&self) -> Option<TextureId> {
-        if let RenderResourceId::Texture(id) = self {
+    pub fn get_texture_view(&self) -> Option<TextureViewId> {
+        if let RenderResourceId::TextureView(id) = self {
             Some(*id)
         } else {
             None

pipelined/bevy_render2/src/render_resource/texture.rs

@@ -10,6 +10,16 @@ impl TextureId {
     }
 }
 
+#[derive(Copy, Clone, Hash, Eq, PartialEq, Debug)]
+pub struct TextureViewId(Uuid);
+
+impl TextureViewId {
+    #[allow(clippy::new_without_default)]
+    pub fn new() -> Self {
+        TextureViewId(Uuid::new_v4())
+    }
+}
+
 #[derive(Copy, Clone, Hash, Eq, PartialEq, Debug)]
 pub struct SamplerId(Uuid);
 

pipelined/bevy_render2/src/render_resource/uniform_vec.rs

@@ -41,15 +41,18 @@ impl<T: AsStd140> UniformVec<T> {
         self.capacity
     }
 
-    pub fn push(&mut self, value: T) -> RenderResourceBinding {
-        if self.values.len() < self.capacity {
-            let binding = RenderResourceBinding::Buffer {
+    pub fn binding(&self) -> RenderResourceBinding {
+        RenderResourceBinding::Buffer {
             buffer: self.uniform_buffer.unwrap(),
-                dynamic_index: Some((self.values.len() * self.item_size) as u32),
             range: 0..self.item_size as u64,
-            };
+        }
+    }
+
+    pub fn push(&mut self, value: T) -> usize {
+        let len = self.values.len();
+        if len < self.capacity {
             self.values.push(value);
-            binding
+            len
         } else {
             panic!(
                 "Cannot push value because capacity of {} has been reached",
@@ -145,14 +148,19 @@ impl<T: AsStd140> DynamicUniformVec<T> {
         self.uniform_vec.uniform_buffer()
     }
 
+    #[inline]
+    pub fn binding(&self) -> RenderResourceBinding {
+        self.uniform_vec.binding()
+    }
+
     #[inline]
     pub fn capacity(&self) -> usize {
         self.uniform_vec.capacity()
     }
 
     #[inline]
-    pub fn push(&mut self, value: T) -> RenderResourceBinding {
-        self.uniform_vec.push(DynamicUniform(value))
+    pub fn push(&mut self, value: T) -> u32 {
+        (self.uniform_vec.push(DynamicUniform(value)) * self.uniform_vec.item_size) as u32
     }
 
     #[inline]

pipelined/bevy_render2/src/renderer/headless_render_resource_context.rs

@@ -1,14 +1,16 @@
-use super::RenderResourceContext;
 use crate::{
-    pipeline::{BindGroupDescriptorId, ComputePipelineDescriptor, RenderPipelineDescriptor, PipelineId},
+    pipeline::{
+        BindGroupDescriptorId, ComputePipelineDescriptor, PipelineId, RenderPipelineDescriptor,
+    },
     render_resource::{
         BindGroup, BufferId, BufferInfo, BufferMapMode, SamplerId, SwapChainDescriptor, TextureId,
+        TextureViewId,
     },
+    renderer::RenderResourceContext,
     shader::{Shader, ShaderId},
-    texture::{SamplerDescriptor, TextureDescriptor},
+    texture::{SamplerDescriptor, TextureDescriptor, TextureViewDescriptor},
 };
 use bevy_utils::HashMap;
-use bevy_window::Window;
 use parking_lot::RwLock;
 use std::{ops::Range, sync::Arc};
 
@@ -16,6 +18,7 @@ use std::{ops::Range, sync::Arc};
 pub struct HeadlessRenderResourceContext {
     buffer_info: Arc<RwLock<HashMap<BufferId, BufferInfo>>>,
     texture_descriptors: Arc<RwLock<HashMap<TextureId, TextureDescriptor>>>,
+    texture_view_descriptors: Arc<RwLock<HashMap<TextureViewId, TextureViewDescriptor>>>,
 }
 
 impl HeadlessRenderResourceContext {
@@ -29,9 +32,7 @@ impl HeadlessRenderResourceContext {
 }
 
 impl RenderResourceContext for HeadlessRenderResourceContext {
-    fn create_swap_chain(&self, _window: &Window) {}
-
-    fn drop_swap_chain_texture(&self, _render_resource: TextureId) {}
+    fn drop_swap_chain_texture(&self, _texture_view: TextureViewId) {}
 
     fn drop_all_swap_chain_textures(&self) {}
 
@@ -45,6 +46,18 @@ impl RenderResourceContext for HeadlessRenderResourceContext {
         texture
     }
 
+    fn create_texture_view(
+        &self,
+        _texture_id: TextureId,
+        texture_view_descriptor: TextureViewDescriptor,
+    ) -> TextureViewId {
+        let texture_view_id = TextureViewId::new();
+        self.texture_view_descriptors
+            .write()
+            .insert(texture_view_id, texture_view_descriptor);
+        texture_view_id
+    }
+
     fn create_buffer(&self, buffer_info: BufferInfo) -> BufferId {
         let buffer = BufferId::new();
         self.add_buffer_info(buffer, buffer_info);
@@ -97,7 +110,14 @@ impl RenderResourceContext for HeadlessRenderResourceContext {
 
     fn remove_sampler(&self, _sampler: SamplerId) {}
 
-    fn create_render_pipeline(&self, _pipeline_descriptor: &RenderPipelineDescriptor) -> PipelineId {
+    fn remove_texture_view(&self, texture_view: TextureViewId) {
+        self.texture_view_descriptors.write().remove(&texture_view);
+    }
+
+    fn create_render_pipeline(
+        &self,
+        _pipeline_descriptor: &RenderPipelineDescriptor,
+    ) -> PipelineId {
         PipelineId::new()
     }
 
@@ -138,7 +158,7 @@ impl RenderResourceContext for HeadlessRenderResourceContext {
 
     fn remove_stale_bind_groups(&self) {}
 
-    fn next_swap_chain_texture(&self, _descriptor: &SwapChainDescriptor) -> TextureId {
-        TextureId::new()
+    fn next_swap_chain_texture(&self, _descriptor: &SwapChainDescriptor) -> TextureViewId {
+        TextureViewId::new()
     }
 }

pipelined/bevy_render2/src/renderer/render_resource_context.rs

@@ -1,12 +1,14 @@
 use crate::{
-    pipeline::{BindGroupDescriptorId, ComputePipelineDescriptor, RenderPipelineDescriptor, PipelineId},
+    pipeline::{
+        BindGroupDescriptorId, ComputePipelineDescriptor, PipelineId, RenderPipelineDescriptor,
+    },
     render_resource::{
         BindGroup, BufferId, BufferInfo, BufferMapMode, SamplerId, SwapChainDescriptor, TextureId,
+        TextureViewId,
     },
     shader::{Shader, ShaderId},
-    texture::{SamplerDescriptor, TextureDescriptor},
+    texture::{SamplerDescriptor, TextureDescriptor, TextureViewDescriptor},
 };
-use bevy_window::Window;
 use downcast_rs::{impl_downcast, Downcast};
 use std::ops::{Deref, DerefMut, Range};
 
@@ -33,13 +35,16 @@ impl DerefMut for RenderResources {
 }
 
 pub trait RenderResourceContext: Downcast + Send + Sync + 'static {
-    // TODO: remove me
-    fn create_swap_chain(&self, window: &Window);
-    fn next_swap_chain_texture(&self, descriptor: &SwapChainDescriptor) -> TextureId;
-    fn drop_swap_chain_texture(&self, resource: TextureId);
+    fn next_swap_chain_texture(&self, descriptor: &SwapChainDescriptor) -> TextureViewId;
+    fn drop_swap_chain_texture(&self, resource: TextureViewId);
     fn drop_all_swap_chain_textures(&self);
     fn create_sampler(&self, sampler_descriptor: &SamplerDescriptor) -> SamplerId;
     fn create_texture(&self, texture_descriptor: TextureDescriptor) -> TextureId;
+    fn create_texture_view(
+        &self,
+        texture_id: TextureId,
+        texture_view_descriptor: TextureViewDescriptor,
+    ) -> TextureViewId;
     fn create_buffer(&self, buffer_info: BufferInfo) -> BufferId;
     // TODO: remove RenderResourceContext here
     fn write_mapped_buffer(
@@ -61,6 +66,7 @@ pub trait RenderResourceContext: Downcast + Send + Sync + 'static {
     fn remove_buffer(&self, buffer: BufferId);
     fn remove_texture(&self, texture: TextureId);
     fn remove_sampler(&self, sampler: SamplerId);
+    fn remove_texture_view(&self, texture_view: TextureViewId);
     fn get_buffer_info(&self, buffer: BufferId) -> Option<BufferInfo>;
     fn get_aligned_uniform_size(&self, size: usize, dynamic: bool) -> usize;
     fn get_aligned_texture_size(&self, data_size: usize) -> usize;

pipelined/bevy_render2/src/shader/shader_reflect.rs

@@ -105,11 +105,24 @@ fn reflect_bind_group(
 }
 
 fn reflect_dimension(type_description: &ReflectTypeDescription) -> TextureViewDimension {
+    let arrayed = type_description.traits.image.arrayed > 0;
     match type_description.traits.image.dim {
         ReflectDimension::Type1d => TextureViewDimension::D1,
-        ReflectDimension::Type2d => TextureViewDimension::D2,
+        ReflectDimension::Type2d => {
+            if arrayed {
+                TextureViewDimension::D2Array
+            } else {
+                TextureViewDimension::D2
+            }
+        }
         ReflectDimension::Type3d => TextureViewDimension::D3,
-        ReflectDimension::Cube => TextureViewDimension::Cube,
+        ReflectDimension::Cube => {
+            if arrayed {
+                TextureViewDimension::CubeArray
+            } else {
+                TextureViewDimension::Cube
+            }
+        }
         dimension => panic!("Unsupported image dimension: {:?}.", dimension),
     }
 }

pipelined/bevy_render2/src/texture/mod.rs

@@ -4,6 +4,7 @@ mod image_texture_loader;
 mod sampler_descriptor;
 #[allow(clippy::module_inception)]
 mod texture;
+mod texture_cache;
 mod texture_descriptor;
 mod texture_dimension;
 
@@ -14,6 +15,7 @@ pub use hdr_texture_loader::*;
 pub use image_texture_loader::*;
 pub use sampler_descriptor::*;
 pub use texture::*;
+pub use texture_cache::*;
 pub use texture_descriptor::*;
 pub use texture_dimension::*;
 
@@ -21,6 +23,7 @@ use crate::{
     render_command::RenderCommandQueue,
     render_resource::{BufferInfo, BufferUsage},
     renderer::{RenderResourceContext, RenderResources},
+    RenderStage,
 };
 use bevy_app::{App, CoreStage, Plugin};
 use bevy_asset::{AddAsset, AssetEvent, Assets, Handle};
@@ -38,10 +41,14 @@ impl Plugin for TexturePlugin {
 
         app.add_system_to_stage(CoreStage::PostUpdate, texture_resource_system.system())
             .add_asset::<Texture>();
+
+        let render_app = app.sub_app_mut(0);
+        render_app
+            .init_resource::<TextureCache>()
+            .add_system_to_stage(RenderStage::Cleanup, update_texture_cache_system.system());
     }
 }
 
-// TODO: remove old system
 pub fn texture_resource_system(
     render_resource_context: Res<RenderResources>,
     mut render_command_queue: ResMut<RenderCommandQueue>,
@@ -57,7 +64,8 @@ pub fn texture_resource_system(
             }
             AssetEvent::Modified { handle } => {
                 changed_textures.insert(handle);
-                remove_current_texture_resources(render_resource_context, handle, &mut textures);
+                // TODO: uncomment this to support mutated textures
+                // remove_current_texture_resources(render_resource_context, handle, &mut textures);
             }
             AssetEvent::Removed { handle } => {
                 remove_current_texture_resources(render_resource_context, handle, &mut textures);
@@ -109,9 +117,13 @@ pub fn texture_resource_system(
                 },
                 &aligned_data,
             );
-            texture.gpu_data = Some(GpuData {
-                texture_id,
-                sampler_id,
+
+            let texture_view_id = render_resource_context
+                .create_texture_view(texture_id, TextureViewDescriptor::default());
+            texture.gpu_data = Some(TextureGpuData {
+                texture: texture_id,
+                texture_view: texture_view_id,
+                sampler: sampler_id,
             });
 
             render_command_queue.copy_buffer_to_texture(
@@ -134,7 +146,7 @@ fn remove_current_texture_resources(
     textures: &mut Assets<Texture>,
 ) {
     if let Some(gpu_data) = textures.get_mut(handle).and_then(|t| t.gpu_data.take()) {
-        render_resource_context.remove_texture(gpu_data.texture_id);
-        render_resource_context.remove_sampler(gpu_data.sampler_id);
+        render_resource_context.remove_texture(gpu_data.texture);
+        render_resource_context.remove_sampler(gpu_data.sampler);
     }
 }

pipelined/bevy_render2/src/texture/texture.rs

@@ -2,7 +2,7 @@ use super::{
     image_texture_conversion::image_to_texture, Extent3d, SamplerDescriptor, TextureDimension,
     TextureFormat,
 };
-use crate::render_resource::{SamplerId, TextureId};
+use crate::render_resource::{SamplerId, TextureId, TextureViewId};
 use bevy_reflect::TypeUuid;
 use thiserror::Error;
 
@@ -11,16 +11,17 @@ pub const SAMPLER_ASSET_INDEX: u64 = 1;
 
 // TODO: this shouldn't live in the Texture type
 #[derive(Debug, Clone)]
-pub struct GpuData {
-    pub texture_id: TextureId,
-    pub sampler_id: SamplerId,
+pub struct TextureGpuData {
+    pub texture: TextureId,
+    pub texture_view: TextureViewId,
+    pub sampler: SamplerId,
 }
 
 #[derive(Debug, Clone, TypeUuid)]
 #[uuid = "6ea26da6-6cf8-4ea2-9986-1d7bf6c17d6f"]
 pub struct Texture {
     pub data: Vec<u8>,
-    pub gpu_data: Option<GpuData>,
+    pub gpu_data: Option<TextureGpuData>,
     pub size: Extent3d,
     pub format: TextureFormat,
     pub dimension: TextureDimension,

pipelined/bevy_render2/src/texture/texture_cache.rs

@@ -0,0 +1,101 @@
+use crate::{
+    render_resource::{TextureId, TextureViewId},
+    renderer::RenderResources,
+    texture::{TextureDescriptor, TextureViewDescriptor},
+};
+use bevy_ecs::prelude::{Res, ResMut};
+use bevy_utils::HashMap;
+
+struct CachedTextureMeta {
+    texture: TextureId,
+    default_view: TextureViewId,
+    taken: bool,
+    frames_since_last_use: usize,
+}
+
+pub struct CachedTexture {
+    pub texture: TextureId,
+    pub default_view: TextureViewId,
+}
+
+#[derive(Default)]
+pub struct TextureCache {
+    textures: HashMap<TextureDescriptor, Vec<CachedTextureMeta>>,
+}
+
+impl TextureCache {
+    pub fn get(
+        &mut self,
+        render_resources: &RenderResources,
+        descriptor: TextureDescriptor,
+    ) -> CachedTexture {
+        match self.textures.entry(descriptor) {
+            std::collections::hash_map::Entry::Occupied(mut entry) => {
+                for texture in entry.get_mut().iter_mut() {
+                    if !texture.taken {
+                        texture.frames_since_last_use = 0;
+                        texture.taken = true;
+                        return CachedTexture {
+                            texture: texture.texture,
+                            default_view: texture.default_view,
+                        };
+                    }
+                }
+
+                let texture_id = render_resources.create_texture(entry.key().clone());
+                let view_id = render_resources
+                    .create_texture_view(texture_id, TextureViewDescriptor::default());
+                entry.get_mut().push(CachedTextureMeta {
+                    texture: texture_id,
+                    default_view: view_id,
+                    frames_since_last_use: 0,
+                    taken: true,
+                });
+                CachedTexture {
+                    texture: texture_id,
+                    default_view: view_id,
+                }
+            }
+            std::collections::hash_map::Entry::Vacant(entry) => {
+                let texture_id = render_resources.create_texture(entry.key().clone());
+                let view_id = render_resources
+                    .create_texture_view(texture_id, TextureViewDescriptor::default());
+                entry.insert(vec![CachedTextureMeta {
+                    texture: texture_id,
+                    default_view: view_id,
+                    taken: true,
+                    frames_since_last_use: 0,
+                }]);
+                CachedTexture {
+                    texture: texture_id,
+                    default_view: view_id,
+                }
+            }
+        }
+    }
+
+    pub fn update(&mut self, render_resources: &RenderResources) {
+        for textures in self.textures.values_mut() {
+            for texture in textures.iter_mut() {
+                texture.frames_since_last_use += 1;
+                texture.taken = false;
+            }
+
+            textures.retain(|texture| {
+                let should_keep = texture.frames_since_last_use < 3;
+                if !should_keep {
+                    render_resources.remove_texture_view(texture.default_view);
+                    render_resources.remove_texture(texture.texture);
+                }
+                should_keep
+            });
+        }
+    }
+}
+
+pub fn update_texture_cache_system(
+    mut texture_cache: ResMut<TextureCache>,
+    render_resources: Res<RenderResources>,
+) {
+    texture_cache.update(&render_resources);
+}

pipelined/bevy_render2/src/texture/texture_descriptor.rs

@@ -1,7 +1,11 @@
+use std::num::NonZeroU32;
+
+use crate::texture::TextureViewDimension;
+
 use super::{Extent3d, Texture, TextureDimension, TextureFormat, TextureUsage};
 
 /// Describes a texture
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
 pub struct TextureDescriptor {
     pub size: Extent3d,
     pub mip_level_count: u32,
@@ -67,3 +71,42 @@ pub enum StorageTextureAccess {
     /// ```
     ReadWrite,
 }
+
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub enum TextureAspect {
+    /// Depth, Stencil, and Color.
+    All,
+    /// Stencil.
+    StencilOnly,
+    /// Depth.
+    DepthOnly,
+}
+
+impl Default for TextureAspect {
+    fn default() -> Self {
+        Self::All
+    }
+}
+
+#[derive(Default, Debug, Copy, Clone, Eq, PartialEq)]
+pub struct TextureViewDescriptor {
+    /// Format of the texture view. At this time, it must be the same as the underlying format of the texture.
+    pub format: Option<TextureFormat>,
+    /// The dimension of the texture view. For 1D textures, this must be `1D`. For 2D textures it must be one of
+    /// `D2`, `D2Array`, `Cube`, and `CubeArray`. For 3D textures it must be `3D`
+    pub dimension: Option<TextureViewDimension>,
+    /// Aspect of the texture. Color textures must be [`TextureAspect::All`].
+    pub aspect: TextureAspect,
+    /// Base mip level.
+    pub base_mip_level: u32,
+    /// Mip level count.
+    /// If `Some(count)`, `base_mip_level + count` must be less or equal to underlying texture mip count.
+    /// If `None`, considered to include the rest of the mipmap levels, but at least 1 in total.
+    pub level_count: Option<NonZeroU32>,
+    /// Base array layer.
+    pub base_array_layer: u32,
+    /// Layer count.
+    /// If `Some(count)`, `base_array_layer + count` must be less or equal to the underlying array count.
+    /// If `None`, considered to include the rest of the array layers, but at least 1 in total.
+    pub array_layer_count: Option<NonZeroU32>,
+}