//! Types for handling [`Bundle`]s. //! //! This module contains the [`Bundle`] trait and some other helper types. pub use bevy_ecs_macros::Bundle; use crate::{ archetype::{ Archetype, ArchetypeId, Archetypes, BundleComponentStatus, ComponentStatus, SpawnBundleStatus, }, component::{Component, ComponentId, ComponentStorage, Components, StorageType, Tick}, entity::{Entities, Entity, EntityLocation}, storage::{SparseSetIndex, SparseSets, Storages, Table, TableRow}, }; use bevy_ecs_macros::all_tuples; use bevy_ptr::OwningPtr; use std::{any::TypeId, collections::HashMap}; /// The `Bundle` trait enables insertion and removal of [`Component`]s from an entity. /// /// Implementors of the `Bundle` trait are called 'bundles'. /// /// Each bundle represents a static set of [`Component`] types. /// Currently, bundles can only contain one of each [`Component`], and will /// panic once initialised if this is not met. /// /// ## Insertion /// /// The primary use for bundles is to add a useful collection of components to an entity. /// /// Adding a value of bundle to an entity will add the components from the set it /// represents to the entity. /// The values of these components are taken from the bundle. /// If an entity already had one of these components, the entity's original component value /// will be overwritten. /// /// Importantly, bundles are only their constituent set of components. /// You **should not** use bundles as a unit of behaviour. /// The behaviour of your app can only be considered in terms of components, as systems, /// which drive the behaviour of a `bevy` application, operate on combinations of /// components. /// /// This rule is also important because multiple bundles may contain the same component type, /// calculated in different ways — adding both of these bundles to one entity /// would create incoherent behaviour. /// This would be unexpected if bundles were treated as an abstraction boundary, as /// the abstraction would be unmaintainable for these cases. /// For example, both `Camera3dBundle` and `Camera2dBundle` contain the `CameraRenderGraph` /// component, but specifying different render graphs to use. /// If the bundles were both added to the same entity, only one of these two bundles would work. /// /// For this reason, there is intentionally no [`Query`] to match whether an entity /// contains the components of a bundle. /// Queries should instead only select the components they logically operate on. /// /// ## Removal /// /// Bundles are also used when removing components from an entity. /// /// Removing a bundle from an entity will remove any of its components attached /// to the entity from the entity. /// That is, if the entity does not have all the components of the bundle, those /// which are present will be removed. /// /// # Implementors /// /// Every type which implements [`Component`] also implements `Bundle`, since /// [`Component`] types can be added to or removed from an entity. /// /// Additionally, [Tuples](`tuple`) of bundles are also [`Bundle`] (with up to 15 bundles). /// These bundles contain the items of the 'inner' bundles. /// This is a convenient shorthand which is primarily used when spawning entities. /// For example, spawning an entity using the bundle `(SpriteBundle {...}, PlayerMarker)` /// will spawn an entity with components required for a 2d sprite, and the `PlayerMarker` component. /// /// [`unit`], otherwise known as [`()`](`unit`), is a [`Bundle`] containing no components (since it /// can also be considered as the empty tuple). /// This can be useful for spawning large numbers of empty entities using /// [`World::spawn_batch`](crate::world::World::spawn_batch). /// /// Tuple bundles can be nested, which can be used to create an anonymous bundle with more than /// 15 items. /// However, in most cases where this is required, the derive macro [`derive@Bundle`] should be /// used instead. /// The derived `Bundle` implementation contains the items of its fields, which all must /// implement `Bundle`. /// As explained above, this includes any [`Component`] type, and other derived bundles. /// /// If you want to add `PhantomData` to your `Bundle` you have to mark it with `#[bundle(ignore)]`. /// ``` /// # use std::marker::PhantomData; /// use bevy_ecs::{component::Component, bundle::Bundle}; /// /// #[derive(Component)] /// struct XPosition(i32); /// #[derive(Component)] /// struct YPosition(i32); /// /// #[derive(Bundle)] /// struct PositionBundle { /// // A bundle can contain components /// x: XPosition, /// y: YPosition, /// } /// /// // You have to implement `Default` for ignored field types in bundle structs. /// #[derive(Default)] /// struct Other(f32); /// /// #[derive(Bundle)] /// struct NamedPointBundle { /// // Or other bundles /// a: PositionBundle, /// // In addition to more components /// z: PointName, /// /// // when you need to use `PhantomData` you have to mark it as ignored /// #[bundle(ignore)] /// _phantom_data: PhantomData /// } /// /// #[derive(Component)] /// struct PointName(String); /// ``` /// /// # Safety /// /// Manual implementations of this trait are unsupported. /// That is, there is no safe way to implement this trait, and you must not do so. /// If you want a type to implement [`Bundle`], you must use [`derive@Bundle`](derive@Bundle). /// /// [`Query`]: crate::system::Query // Some safety points: // - [`Bundle::component_ids`] must return the [`ComponentId`] for each component type in the // bundle, in the _exact_ order that [`Bundle::get_components`] is called. // - [`Bundle::from_components`] must call `func` exactly once for each [`ComponentId`] returned by // [`Bundle::component_ids`]. pub unsafe trait Bundle: Send + Sync + 'static { /// Gets this [`Bundle`]'s component ids, in the order of this bundle's [`Component`]s #[doc(hidden)] fn component_ids( components: &mut Components, storages: &mut Storages, ids: &mut impl FnMut(ComponentId), ); /// Calls `func`, which should return data for each component in the bundle, in the order of /// this bundle's [`Component`]s /// /// # Safety /// Caller must return data for each component in the bundle, in the order of this bundle's /// [`Component`]s #[doc(hidden)] unsafe fn from_components(ctx: &mut T, func: &mut F) -> Self where // Ensure that the `OwningPtr` is used correctly F: for<'a> FnMut(&'a mut T) -> OwningPtr<'a>, Self: Sized; // SAFETY: // The `StorageType` argument passed into [`Bundle::get_components`] must be correct for the // component being fetched. // /// Calls `func` on each value, in the order of this bundle's [`Component`]s. This passes /// ownership of the component values to `func`. #[doc(hidden)] fn get_components(self, func: &mut impl FnMut(StorageType, OwningPtr<'_>)); } // SAFETY: // - `Bundle::component_ids` calls `ids` for C's component id (and nothing else) // - `Bundle::get_components` is called exactly once for C and passes the component's storage type based on it's associated constant. // - `Bundle::from_components` calls `func` exactly once for C, which is the exact value returned by `Bundle::component_ids`. unsafe impl Bundle for C { fn component_ids( components: &mut Components, storages: &mut Storages, ids: &mut impl FnMut(ComponentId), ) { ids(components.init_component::(storages)); } unsafe fn from_components(ctx: &mut T, func: &mut F) -> Self where // Ensure that the `OwningPtr` is used correctly F: for<'a> FnMut(&'a mut T) -> OwningPtr<'a>, Self: Sized, { // Safety: The id given in `component_ids` is for `Self` func(ctx).read() } #[inline] fn get_components(self, func: &mut impl FnMut(StorageType, OwningPtr<'_>)) { OwningPtr::make(self, |ptr| func(C::Storage::STORAGE_TYPE, ptr)); } } macro_rules! tuple_impl { ($($name: ident),*) => { // SAFETY: // - `Bundle::component_ids` calls `ids` for each component type in the // bundle, in the exact order that `Bundle::get_components` is called. // - `Bundle::from_components` calls `func` exactly once for each `ComponentId` returned by `Bundle::component_ids`. // - `Bundle::get_components` is called exactly once for each member. Relies on the above implementation to pass the correct // `StorageType` into the callback. unsafe impl<$($name: Bundle),*> Bundle for ($($name,)*) { #[allow(unused_variables)] fn component_ids(components: &mut Components, storages: &mut Storages, ids: &mut impl FnMut(ComponentId)){ $(<$name as Bundle>::component_ids(components, storages, ids);)* } #[allow(unused_variables, unused_mut)] #[allow(clippy::unused_unit)] unsafe fn from_components(ctx: &mut T, func: &mut F) -> Self where F: FnMut(&mut T) -> OwningPtr<'_> { // Rust guarantees that tuple calls are evaluated 'left to right'. // https://doc.rust-lang.org/reference/expressions.html#evaluation-order-of-operands ($(<$name as Bundle>::from_components(ctx, func),)*) } #[allow(unused_variables, unused_mut)] #[inline(always)] fn get_components(self, func: &mut impl FnMut(StorageType, OwningPtr<'_>)) { #[allow(non_snake_case)] let ($(mut $name,)*) = self; $( $name.get_components(&mut *func); )* } } } } all_tuples!(tuple_impl, 0, 15, B); #[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)] pub struct BundleId(usize); impl BundleId { #[inline] pub fn index(self) -> usize { self.0 } } impl SparseSetIndex for BundleId { #[inline] fn sparse_set_index(&self) -> usize { self.index() } fn get_sparse_set_index(value: usize) -> Self { Self(value) } } pub struct BundleInfo { pub(crate) id: BundleId, pub(crate) component_ids: Vec, } impl BundleInfo { #[inline] pub fn id(&self) -> BundleId { self.id } #[inline] pub fn components(&self) -> &[ComponentId] { &self.component_ids } pub(crate) fn get_bundle_inserter<'a, 'b>( &'b self, entities: &'a mut Entities, archetypes: &'a mut Archetypes, components: &mut Components, storages: &'a mut Storages, archetype_id: ArchetypeId, change_tick: u32, ) -> BundleInserter<'a, 'b> { let new_archetype_id = self.add_bundle_to_archetype(archetypes, storages, components, archetype_id); let archetypes_ptr = archetypes.archetypes.as_mut_ptr(); if new_archetype_id == archetype_id { let archetype = &mut archetypes[archetype_id]; let table_id = archetype.table_id(); BundleInserter { bundle_info: self, archetype, entities, sparse_sets: &mut storages.sparse_sets, table: &mut storages.tables[table_id], archetypes_ptr, change_tick, result: InsertBundleResult::SameArchetype, } } else { let (archetype, new_archetype) = archetypes.get_2_mut(archetype_id, new_archetype_id); let table_id = archetype.table_id(); if table_id == new_archetype.table_id() { BundleInserter { bundle_info: self, archetype, archetypes_ptr, entities, sparse_sets: &mut storages.sparse_sets, table: &mut storages.tables[table_id], change_tick, result: InsertBundleResult::NewArchetypeSameTable { new_archetype }, } } else { let (table, new_table) = storages .tables .get_2_mut(table_id, new_archetype.table_id()); BundleInserter { bundle_info: self, archetype, sparse_sets: &mut storages.sparse_sets, entities, archetypes_ptr, table, change_tick, result: InsertBundleResult::NewArchetypeNewTable { new_archetype, new_table, }, } } } } pub(crate) fn get_bundle_spawner<'a, 'b>( &'b self, entities: &'a mut Entities, archetypes: &'a mut Archetypes, components: &mut Components, storages: &'a mut Storages, change_tick: u32, ) -> BundleSpawner<'a, 'b> { let new_archetype_id = self.add_bundle_to_archetype(archetypes, storages, components, ArchetypeId::EMPTY); let archetype = &mut archetypes[new_archetype_id]; let table = &mut storages.tables[archetype.table_id()]; BundleSpawner { archetype, bundle_info: self, table, entities, sparse_sets: &mut storages.sparse_sets, change_tick, } } /// This writes components from a given [`Bundle`] to the given entity. /// /// # Safety /// /// `bundle_component_status` must return the "correct" [`ComponentStatus`] for each component /// in the [`Bundle`], with respect to the entity's original archetype (prior to the bundle being added) /// For example, if the original archetype already has `ComponentA` and `T` also has `ComponentA`, the status /// should be `Mutated`. If the original archetype does not have `ComponentA`, the status should be `Added`. /// When "inserting" a bundle into an existing entity, [`AddBundle`](crate::archetype::AddBundle) /// should be used, which will report `Added` vs `Mutated` status based on the current archetype's structure. /// When spawning a bundle, [`SpawnBundleStatus`] can be used instead, which removes the need /// to look up the [`AddBundle`](crate::archetype::AddBundle) in the archetype graph, which requires /// ownership of the entity's current archetype. /// /// `table` must be the "new" table for `entity`. `table_row` must have space allocated for the /// `entity`, `bundle` must match this [`BundleInfo`]'s type #[inline] #[allow(clippy::too_many_arguments)] unsafe fn write_components( &self, table: &mut Table, sparse_sets: &mut SparseSets, bundle_component_status: &S, entity: Entity, table_row: TableRow, change_tick: u32, bundle: T, ) { // NOTE: get_components calls this closure on each component in "bundle order". // bundle_info.component_ids are also in "bundle order" let mut bundle_component = 0; bundle.get_components(&mut |storage_type, component_ptr| { let component_id = *self.component_ids.get_unchecked(bundle_component); match storage_type { StorageType::Table => { let column = table.get_column_mut(component_id).unwrap(); // SAFETY: bundle_component is a valid index for this bundle match bundle_component_status.get_status(bundle_component) { ComponentStatus::Added => { column.initialize(table_row, component_ptr, Tick::new(change_tick)); } ComponentStatus::Mutated => { column.replace(table_row, component_ptr, change_tick); } } } StorageType::SparseSet => { sparse_sets.get_mut(component_id).unwrap().insert( entity, component_ptr, change_tick, ); } } bundle_component += 1; }); } /// Adds a bundle to the given archetype and returns the resulting archetype. This could be the /// same [`ArchetypeId`], in the event that adding the given bundle does not result in an /// [`Archetype`] change. Results are cached in the [`Archetype`] graph to avoid redundant work. pub(crate) fn add_bundle_to_archetype( &self, archetypes: &mut Archetypes, storages: &mut Storages, components: &mut Components, archetype_id: ArchetypeId, ) -> ArchetypeId { if let Some(add_bundle_id) = archetypes[archetype_id].edges().get_add_bundle(self.id) { return add_bundle_id; } let mut new_table_components = Vec::new(); let mut new_sparse_set_components = Vec::new(); let mut bundle_status = Vec::with_capacity(self.component_ids.len()); let current_archetype = &mut archetypes[archetype_id]; for component_id in self.component_ids.iter().cloned() { if current_archetype.contains(component_id) { bundle_status.push(ComponentStatus::Mutated); } else { bundle_status.push(ComponentStatus::Added); // SAFETY: component_id exists let component_info = unsafe { components.get_info_unchecked(component_id) }; match component_info.storage_type() { StorageType::Table => new_table_components.push(component_id), StorageType::SparseSet => new_sparse_set_components.push(component_id), } } } if new_table_components.is_empty() && new_sparse_set_components.is_empty() { let edges = current_archetype.edges_mut(); // the archetype does not change when we add this bundle edges.insert_add_bundle(self.id, archetype_id, bundle_status); archetype_id } else { let table_id; let table_components; let sparse_set_components; // the archetype changes when we add this bundle. prepare the new archetype and storages { let current_archetype = &archetypes[archetype_id]; table_components = if new_table_components.is_empty() { // if there are no new table components, we can keep using this table table_id = current_archetype.table_id(); current_archetype.table_components().collect() } else { new_table_components.extend(current_archetype.table_components()); // sort to ignore order while hashing new_table_components.sort(); // SAFETY: all component ids in `new_table_components` exist table_id = unsafe { storages .tables .get_id_or_insert(&new_table_components, components) }; new_table_components }; sparse_set_components = if new_sparse_set_components.is_empty() { current_archetype.sparse_set_components().collect() } else { new_sparse_set_components.extend(current_archetype.sparse_set_components()); // sort to ignore order while hashing new_sparse_set_components.sort(); new_sparse_set_components }; }; let new_archetype_id = archetypes.get_id_or_insert(table_id, table_components, sparse_set_components); // add an edge from the old archetype to the new archetype archetypes[archetype_id].edges_mut().insert_add_bundle( self.id, new_archetype_id, bundle_status, ); new_archetype_id } } } pub(crate) struct BundleInserter<'a, 'b> { pub(crate) archetype: &'a mut Archetype, pub(crate) entities: &'a mut Entities, bundle_info: &'b BundleInfo, table: &'a mut Table, sparse_sets: &'a mut SparseSets, result: InsertBundleResult<'a>, archetypes_ptr: *mut Archetype, change_tick: u32, } pub(crate) enum InsertBundleResult<'a> { SameArchetype, NewArchetypeSameTable { new_archetype: &'a mut Archetype, }, NewArchetypeNewTable { new_archetype: &'a mut Archetype, new_table: &'a mut Table, }, } impl<'a, 'b> BundleInserter<'a, 'b> { /// # Safety /// `entity` must currently exist in the source archetype for this inserter. `archetype_row` /// must be `entity`'s location in the archetype. `T` must match this [`BundleInfo`]'s type #[inline] pub unsafe fn insert( &mut self, entity: Entity, location: EntityLocation, bundle: T, ) -> EntityLocation { match &mut self.result { InsertBundleResult::SameArchetype => { // PERF: this could be looked up during Inserter construction and stored (but borrowing makes this nasty) let add_bundle = self .archetype .edges() .get_add_bundle_internal(self.bundle_info.id) .unwrap(); self.bundle_info.write_components( self.table, self.sparse_sets, add_bundle, entity, location.table_row, self.change_tick, bundle, ); location } InsertBundleResult::NewArchetypeSameTable { new_archetype } => { let result = self.archetype.swap_remove(location.archetype_row); if let Some(swapped_entity) = result.swapped_entity { self.entities.set(swapped_entity.index(), location); } let new_location = new_archetype.allocate(entity, result.table_row); self.entities.set(entity.index(), new_location); // PERF: this could be looked up during Inserter construction and stored (but borrowing makes this nasty) let add_bundle = self .archetype .edges() .get_add_bundle_internal(self.bundle_info.id) .unwrap(); self.bundle_info.write_components( self.table, self.sparse_sets, add_bundle, entity, result.table_row, self.change_tick, bundle, ); new_location } InsertBundleResult::NewArchetypeNewTable { new_archetype, new_table, } => { let result = self.archetype.swap_remove(location.archetype_row); if let Some(swapped_entity) = result.swapped_entity { self.entities.set(swapped_entity.index(), location); } // PERF: store "non bundle" components in edge, then just move those to avoid // redundant copies let move_result = self .table .move_to_superset_unchecked(result.table_row, new_table); let new_location = new_archetype.allocate(entity, move_result.new_row); self.entities.set(entity.index(), new_location); // if an entity was moved into this entity's table spot, update its table row if let Some(swapped_entity) = move_result.swapped_entity { let swapped_location = self.entities.get(swapped_entity).unwrap(); let swapped_archetype = if self.archetype.id() == swapped_location.archetype_id { &mut *self.archetype } else if new_archetype.id() == swapped_location.archetype_id { new_archetype } else { // SAFETY: the only two borrowed archetypes are above and we just did collision checks &mut *self .archetypes_ptr .add(swapped_location.archetype_id.index()) }; swapped_archetype .set_entity_table_row(swapped_location.archetype_row, result.table_row); } // PERF: this could be looked up during Inserter construction and stored (but borrowing makes this nasty) let add_bundle = self .archetype .edges() .get_add_bundle_internal(self.bundle_info.id) .unwrap(); self.bundle_info.write_components( new_table, self.sparse_sets, add_bundle, entity, move_result.new_row, self.change_tick, bundle, ); new_location } } } } pub(crate) struct BundleSpawner<'a, 'b> { pub(crate) archetype: &'a mut Archetype, pub(crate) entities: &'a mut Entities, bundle_info: &'b BundleInfo, table: &'a mut Table, sparse_sets: &'a mut SparseSets, change_tick: u32, } impl<'a, 'b> BundleSpawner<'a, 'b> { pub fn reserve_storage(&mut self, additional: usize) { self.archetype.reserve(additional); self.table.reserve(additional); } /// # Safety /// `entity` must be allocated (but non-existent), `T` must match this [`BundleInfo`]'s type #[inline] pub unsafe fn spawn_non_existent( &mut self, entity: Entity, bundle: T, ) -> EntityLocation { let table_row = self.table.allocate(entity); let location = self.archetype.allocate(entity, table_row); self.bundle_info.write_components( self.table, self.sparse_sets, &SpawnBundleStatus, entity, table_row, self.change_tick, bundle, ); self.entities.set(entity.index(), location); location } /// # Safety /// `T` must match this [`BundleInfo`]'s type #[inline] pub unsafe fn spawn(&mut self, bundle: T) -> Entity { let entity = self.entities.alloc(); // SAFETY: entity is allocated (but non-existent), `T` matches this BundleInfo's type self.spawn_non_existent(entity, bundle); entity } } #[derive(Default)] pub struct Bundles { bundle_infos: Vec, bundle_ids: HashMap, } impl Bundles { #[inline] pub fn get(&self, bundle_id: BundleId) -> Option<&BundleInfo> { self.bundle_infos.get(bundle_id.index()) } #[inline] pub fn get_id(&self, type_id: TypeId) -> Option { self.bundle_ids.get(&type_id).cloned() } pub(crate) fn init_info<'a, T: Bundle>( &'a mut self, components: &mut Components, storages: &mut Storages, ) -> &'a BundleInfo { let bundle_infos = &mut self.bundle_infos; let id = self.bundle_ids.entry(TypeId::of::()).or_insert_with(|| { let mut component_ids = Vec::new(); T::component_ids(components, storages, &mut |id| component_ids.push(id)); let id = BundleId(bundle_infos.len()); let bundle_info = // SAFETY: T::component_id ensures info was created unsafe { initialize_bundle(std::any::type_name::(), component_ids, id) }; bundle_infos.push(bundle_info); id }); // SAFETY: index either exists, or was initialized unsafe { self.bundle_infos.get_unchecked(id.0) } } } /// # Safety /// /// `component_id` must be valid [`ComponentId`]'s unsafe fn initialize_bundle( bundle_type_name: &'static str, component_ids: Vec, id: BundleId, ) -> BundleInfo { let mut deduped = component_ids.clone(); deduped.sort(); deduped.dedup(); assert!( deduped.len() == component_ids.len(), "Bundle {bundle_type_name} has duplicate components", ); BundleInfo { id, component_ids } }