Commit graph

14 commits

Author SHA1 Message Date
Joona Aalto
0166db33f7
Deprecate shapes in bevy_render::mesh::shape (#11773)
# Objective

#11431 and #11688 implemented meshing support for Bevy's new geometric
primitives. The next step is to deprecate the shapes in
`bevy_render::mesh::shape` and to later remove them completely for 0.14.

## Solution

Deprecate the shapes and reduce code duplication by utilizing the
primitive meshing API for the old shapes where possible.

Note that some shapes have behavior that can't be exactly reproduced
with the new primitives yet:

- `Box` is more of an AABB with min/max extents
- `Plane` supports a subdivision count
- `Quad` has a `flipped` property

These types have not been changed to utilize the new primitives yet.

---

## Changelog

- Deprecated all shapes in `bevy_render::mesh::shape`
- Changed all examples to use new primitives for meshing

## Migration Guide

Bevy has previously used rendering-specific types like `UVSphere` and
`Quad` for primitive mesh shapes. These have now been deprecated to use
the geometric primitives newly introduced in version 0.13.

Some examples:

```rust
let before = meshes.add(shape::Box::new(5.0, 0.15, 5.0));
let after = meshes.add(Cuboid::new(5.0, 0.15, 5.0));

let before = meshes.add(shape::Quad::default());
let after = meshes.add(Rectangle::default());

let before = meshes.add(shape::Plane::from_size(5.0));
// The surface normal can now also be specified when using `new`
let after = meshes.add(Plane3d::default().mesh().size(5.0, 5.0));

let before = meshes.add(
    Mesh::try_from(shape::Icosphere {
        radius: 0.5,
        subdivisions: 5,
    })
    .unwrap(),
);
let after = meshes.add(Sphere::new(0.5).mesh().ico(5).unwrap());
```
2024-02-08 18:01:34 +00:00
JMS55
fcd7c0fc3d
Exposure settings (adopted) (#11347)
Rebased and finished version of
https://github.com/bevyengine/bevy/pull/8407. Huge thanks to @GitGhillie
for adjusting all the examples, and the many other people who helped
write this PR (@superdump , @coreh , among others) :)

Fixes https://github.com/bevyengine/bevy/issues/8369

---

## Changelog
- Added a `brightness` control to `Skybox`.
- Added an `intensity` control to `EnvironmentMapLight`.
- Added `ExposureSettings` and `PhysicalCameraParameters` for
controlling exposure of 3D cameras.
- Removed the baked-in `DirectionalLight` exposure Bevy previously
hardcoded internally.

## Migration Guide
- If using a `Skybox` or `EnvironmentMapLight`, use the new `brightness`
and `intensity` controls to adjust their strength.
- All 3D scene will now have different apparent brightnesses due to Bevy
implementing proper exposure controls. You will have to adjust the
intensity of your lights and/or your camera exposure via the new
`ExposureSettings` component to compensate.

---------

Co-authored-by: Robert Swain <robert.swain@gmail.com>
Co-authored-by: GitGhillie <jillisnoordhoek@gmail.com>
Co-authored-by: Marco Buono <thecoreh@gmail.com>
Co-authored-by: vero <email@atlasdostal.com>
Co-authored-by: atlas dostal <rodol@rivalrebels.com>
2024-01-16 14:53:21 +00:00
Joona Aalto
a795de30b4
Use impl Into<A> for Assets::add (#10878)
# Motivation

When spawning entities into a scene, it is very common to create assets
like meshes and materials and to add them via asset handles. A common
setup might look like this:

```rust
fn setup(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
) {
    commands.spawn(PbrBundle {
        mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
        material: materials.add(StandardMaterial::from(Color::RED)),
        ..default()
    });
}
```

Let's take a closer look at the part that adds the assets using `add`.

```rust
mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
material: materials.add(StandardMaterial::from(Color::RED)),
```

Here, "mesh" and "material" are both repeated three times. It's very
explicit, but I find it to be a bit verbose. In addition to being more
code to read and write, the extra characters can sometimes also lead to
the code being formatted to span multiple lines even though the core
task, adding e.g. a primitive mesh, is extremely simple.

A way to address this is by using `.into()`:

```rust
mesh: meshes.add(shape::Cube { size: 1.0 }.into()),
material: materials.add(Color::RED.into()),
```

This is fine, but from the names and the type of `meshes`, we already
know what the type should be. It's very clear that `Cube` should be
turned into a `Mesh` because of the context it's used in. `.into()` is
just seven characters, but it's so common that it quickly adds up and
gets annoying.

It would be nice if you could skip all of the conversion and let Bevy
handle it for you:

```rust
mesh: meshes.add(shape::Cube { size: 1.0 }),
material: materials.add(Color::RED),
```

# Objective

Make adding assets more ergonomic by making `Assets::add` take an `impl
Into<A>` instead of `A`.

## Solution

`Assets::add` now takes an `impl Into<A>` instead of `A`, so e.g. this
works:

```rust
    commands.spawn(PbrBundle {
        mesh: meshes.add(shape::Cube { size: 1.0 }),
        material: materials.add(Color::RED),
        ..default()
    });
```

I also changed all examples to use this API, which increases consistency
as well because `Mesh::from` and `into` were being used arbitrarily even
in the same file. This also gets rid of some lines of code because
formatting is nicer.

---

## Changelog

- `Assets::add` now takes an `impl Into<A>` instead of `A`
- Examples don't use `T::from(K)` or `K.into()` when adding assets

## Migration Guide

Some `into` calls that worked previously might now be broken because of
the new trait bounds. You need to either remove `into` or perform the
conversion explicitly with `from`:

```rust
// Doesn't compile
let mesh_handle = meshes.add(shape::Cube { size: 1.0 }.into()),

// These compile
let mesh_handle = meshes.add(shape::Cube { size: 1.0 }),
let mesh_handle = meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
```

## Concerns

I believe the primary concerns might be:

1. Is this too implicit?
2. Does this increase codegen bloat?

Previously, the two APIs were using `into` or `from`, and now it's
"nothing" or `from`. You could argue that `into` is slightly more
explicit than "nothing" in cases like the earlier examples where a
`Color` gets converted to e.g. a `StandardMaterial`, but I personally
don't think `into` adds much value even in this case, and you could
still see the actual type from the asset type.

As for codegen bloat, I doubt it adds that much, but I'm not very
familiar with the details of codegen. I personally value the user-facing
code reduction and ergonomics improvements that these changes would
provide, but it might be worth checking the other effects in more
detail.

Another slight concern is migration pain; apps might have a ton of
`into` calls that would need to be removed, and it did take me a while
to do so for Bevy itself (maybe around 20-40 minutes). However, I think
the fact that there *are* so many `into` calls just highlights that the
API could be made nicer, and I'd gladly migrate my own projects for it.
2024-01-08 22:14:43 +00:00
Carter Anderson
aefe1f0739
Schedule-First: the new and improved add_systems (#8079)
Co-authored-by: Mike <mike.hsu@gmail.com>
2023-03-18 01:45:34 +00:00
JoJoJet
fd1af7c8b8
Replace multiple calls to add_system with add_systems (#8001) 2023-03-10 18:15:22 +00:00
Carter Anderson
dcc03724a5 Base Sets (#7466)
# Objective

NOTE: This depends on #7267 and should not be merged until #7267 is merged. If you are reviewing this before that is merged, I highly recommend viewing the Base Sets commit instead of trying to find my changes amongst those from #7267.

"Default sets" as described by the [Stageless RFC](https://github.com/bevyengine/rfcs/pull/45) have some [unfortunate consequences](https://github.com/bevyengine/bevy/discussions/7365).

## Solution

This adds "base sets" as a variant of `SystemSet`:

A set is a "base set" if `SystemSet::is_base` returns `true`. Typically this will be opted-in to using the `SystemSet` derive:

```rust
#[derive(SystemSet, Clone, Hash, Debug, PartialEq, Eq)]
#[system_set(base)]
enum MyBaseSet {
  A,
  B,
}
``` 

**Base sets are exclusive**: a system can belong to at most one "base set". Adding a system to more than one will result in an error. When possible we fail immediately during system-config-time with a nice file + line number. For the more nested graph-ey cases, this will fail at the final schedule build. 

**Base sets cannot belong to other sets**: this is where the word "base" comes from

Systems and Sets can only be added to base sets using `in_base_set`. Calling `in_set` with a base set will fail. As will calling `in_base_set` with a normal set.

```rust
app.add_system(foo.in_base_set(MyBaseSet::A))
       // X must be a normal set ... base sets cannot be added to base sets
       .configure_set(X.in_base_set(MyBaseSet::A))
```

Base sets can still be configured like normal sets:

```rust
app.add_system(MyBaseSet::B.after(MyBaseSet::Ap))
``` 

The primary use case for base sets is enabling a "default base set":

```rust
schedule.set_default_base_set(CoreSet::Update)
  // this will belong to CoreSet::Update by default
  .add_system(foo)
  // this will override the default base set with PostUpdate
  .add_system(bar.in_base_set(CoreSet::PostUpdate))
```

This allows us to build apis that work by default in the standard Bevy style. This is a rough analog to the "default stage" model, but it use the new "stageless sets" model instead, with all of the ordering flexibility (including exclusive systems) that it provides.

---

## Changelog

- Added "base sets" and ported CoreSet to use them.

## Migration Guide

TODO
2023-02-06 03:10:08 +00:00
Alice Cecile
206c7ce219 Migrate engine to Schedule v3 (#7267)
Huge thanks to @maniwani, @devil-ira, @hymm, @cart, @superdump and @jakobhellermann for the help with this PR.

# Objective

- Followup #6587.
- Minimal integration for the Stageless Scheduling RFC: https://github.com/bevyengine/rfcs/pull/45

## Solution

- [x]  Remove old scheduling module
- [x] Migrate new methods to no longer use extension methods
- [x] Fix compiler errors
- [x] Fix benchmarks
- [x] Fix examples
- [x] Fix docs
- [x] Fix tests

## Changelog

### Added

- a large number of methods on `App` to work with schedules ergonomically
- the `CoreSchedule` enum
- `App::add_extract_system` via the `RenderingAppExtension` trait extension method
- the private `prepare_view_uniforms` system now has a public system set for scheduling purposes, called `ViewSet::PrepareUniforms`

### Removed

- stages, and all code that mentions stages
- states have been dramatically simplified, and no longer use a stack
- `RunCriteriaLabel`
- `AsSystemLabel` trait
- `on_hierarchy_reports_enabled` run criteria (now just uses an ad hoc resource checking run condition)
- systems in `RenderSet/Stage::Extract` no longer warn when they do not read data from the main world
- `RunCriteriaLabel`
- `transform_propagate_system_set`: this was a nonstandard pattern that didn't actually provide enough control. The systems are already `pub`: the docs have been updated to ensure that the third-party usage is clear.

### Changed

- `System::default_labels` is now `System::default_system_sets`.
- `App::add_default_labels` is now `App::add_default_sets`
- `CoreStage` and `StartupStage` enums are now `CoreSet` and `StartupSet`
- `App::add_system_set` was renamed to `App::add_systems`
- The `StartupSchedule` label is now defined as part of the `CoreSchedules` enum
-  `.label(SystemLabel)` is now referred to as `.in_set(SystemSet)`
- `SystemLabel` trait was replaced by `SystemSet`
- `SystemTypeIdLabel<T>` was replaced by `SystemSetType<T>`
- The `ReportHierarchyIssue` resource now has a public constructor (`new`), and implements `PartialEq`
- Fixed time steps now use a schedule (`CoreSchedule::FixedTimeStep`) rather than a run criteria.
- Adding rendering extraction systems now panics rather than silently failing if no subapp with the `RenderApp` label is found.
- the `calculate_bounds` system, with the `CalculateBounds` label, is now in `CoreSet::Update`, rather than in `CoreSet::PostUpdate` before commands are applied. 
- `SceneSpawnerSystem` now runs under `CoreSet::Update`, rather than `CoreStage::PreUpdate.at_end()`.
- `bevy_pbr::add_clusters` is no longer an exclusive system
- the top level `bevy_ecs::schedule` module was replaced with `bevy_ecs::scheduling`
- `tick_global_task_pools_on_main_thread` is no longer run as an exclusive system. Instead, it has been replaced by `tick_global_task_pools`, which uses a `NonSend` resource to force running on the main thread.

## Migration Guide

- Calls to `.label(MyLabel)` should be replaced with `.in_set(MySet)`
- Stages have been removed. Replace these with system sets, and then add command flushes using the `apply_system_buffers` exclusive system where needed.
- The `CoreStage`, `StartupStage, `RenderStage` and `AssetStage`  enums have been replaced with `CoreSet`, `StartupSet, `RenderSet` and `AssetSet`. The same scheduling guarantees have been preserved.
  - Systems are no longer added to `CoreSet::Update` by default. Add systems manually if this behavior is needed, although you should consider adding your game logic systems to `CoreSchedule::FixedTimestep` instead for more reliable framerate-independent behavior.
  - Similarly, startup systems are no longer part of `StartupSet::Startup` by default. In most cases, this won't matter to you.
  - For example, `add_system_to_stage(CoreStage::PostUpdate, my_system)` should be replaced with 
  - `add_system(my_system.in_set(CoreSet::PostUpdate)`
- When testing systems or otherwise running them in a headless fashion, simply construct and run a schedule using `Schedule::new()` and `World::run_schedule` rather than constructing stages
- Run criteria have been renamed to run conditions. These can now be combined with each other and with states.
- Looping run criteria and state stacks have been removed. Use an exclusive system that runs a schedule if you need this level of control over system control flow.
- For app-level control flow over which schedules get run when (such as for rollback networking), create your own schedule and insert it under the `CoreSchedule::Outer` label.
- Fixed timesteps are now evaluated in a schedule, rather than controlled via run criteria. The `run_fixed_timestep` system runs this schedule between `CoreSet::First` and `CoreSet::PreUpdate` by default.
- Command flush points introduced by `AssetStage` have been removed. If you were relying on these, add them back manually.
- Adding extract systems is now typically done directly on the main app. Make sure the `RenderingAppExtension` trait is in scope, then call `app.add_extract_system(my_system)`.
- the `calculate_bounds` system, with the `CalculateBounds` label, is now in `CoreSet::Update`, rather than in `CoreSet::PostUpdate` before commands are applied. You may need to order your movement systems to occur before this system in order to avoid system order ambiguities in culling behavior.
- the `RenderLabel` `AppLabel` was renamed to `RenderApp` for clarity
- `App::add_state` now takes 0 arguments: the starting state is set based on the `Default` impl.
- Instead of creating `SystemSet` containers for systems that run in stages, simply use `.on_enter::<State::Variant>()` or its `on_exit` or `on_update` siblings.
- `SystemLabel` derives should be replaced with `SystemSet`. You will also need to add the `Debug`, `PartialEq`, `Eq`, and `Hash` traits to satisfy the new trait bounds.
- `with_run_criteria` has been renamed to `run_if`. Run criteria have been renamed to run conditions for clarity, and should now simply return a bool.
- States have been dramatically simplified: there is no longer a "state stack". To queue a transition to the next state, call `NextState::set`

## TODO

- [x] remove dead methods on App and World
- [x] add `App::add_system_to_schedule` and `App::add_systems_to_schedule`
- [x] avoid adding the default system set at inappropriate times
- [x] remove any accidental cycles in the default plugins schedule
- [x] migrate benchmarks
- [x] expose explicit labels for the built-in command flush points
- [x] migrate engine code
- [x] remove all mentions of stages from the docs
- [x] verify docs for States
- [x] fix uses of exclusive systems that use .end / .at_start / .before_commands
- [x] migrate RenderStage and AssetStage
- [x] migrate examples
- [x] ensure that transform propagation is exported in a sufficiently public way (the systems are already pub)
- [x] ensure that on_enter schedules are run at least once before the main app
- [x] re-enable opt-in to execution order ambiguities
- [x] revert change to `update_bounds` to ensure it runs in `PostUpdate`
- [x] test all examples
  - [x] unbreak directional lights
  - [x] unbreak shadows (see 3d_scene, 3d_shape, lighting, transparaency_3d examples)
  - [x] game menu example shows loading screen and menu simultaneously
  - [x] display settings menu is a blank screen
  - [x] `without_winit` example panics
- [x] ensure all tests pass
  - [x] SubApp doc test fails
  - [x] runs_spawn_local tasks fails
  - [x] [Fix panic_when_hierachy_cycle test hanging](https://github.com/alice-i-cecile/bevy/pull/120)

## Points of Difficulty and Controversy

**Reviewers, please give feedback on these and look closely**

1.  Default sets, from the RFC, have been removed. These added a tremendous amount of implicit complexity and result in hard to debug scheduling errors. They're going to be tackled in the form of "base sets" by @cart in a followup.
2. The outer schedule controls which schedule is run when `App::update` is called.
3. I implemented `Label for `Box<dyn Label>` for our label types. This enables us to store schedule labels in concrete form, and then later run them. I ran into the same set of problems when working with one-shot systems. We've previously investigated this pattern in depth, and it does not appear to lead to extra indirection with nested boxes.
4. `SubApp::update` simply runs the default schedule once. This sucks, but this whole API is incomplete and this was the minimal changeset.
5. `time_system` and `tick_global_task_pools_on_main_thread` no longer use exclusive systems to attempt to force scheduling order
6. Implemetnation strategy for fixed timesteps
7. `AssetStage` was migrated to `AssetSet` without reintroducing command flush points. These did not appear to be used, and it's nice to remove these bottlenecks.
8. Migration of `bevy_render/lib.rs` and pipelined rendering. The logic here is unusually tricky, as we have complex scheduling requirements.

## Future Work (ideally before 0.10)

- Rename schedule_v3 module to schedule or scheduling
- Add a derive macro to states, and likely a `EnumIter` trait of some form
- Figure out what exactly to do with the "systems added should basically work by default" problem
- Improve ergonomics for working with fixed timesteps and states
- Polish FixedTime API to match Time
- Rebase and merge #7415
- Resolve all internal ambiguities (blocked on better tools, especially #7442)
- Add "base sets" to replace the removed default sets.
2023-02-06 02:04:50 +00:00
Carter Anderson
01aedc8431 Spawn now takes a Bundle (#6054)
# Objective

Now that we can consolidate Bundles and Components under a single insert (thanks to #2975 and #6039), almost 100% of world spawns now look like `world.spawn().insert((Some, Tuple, Here))`. Spawning an entity without any components is an extremely uncommon pattern, so it makes sense to give spawn the "first class" ergonomic api. This consolidated api should be made consistent across all spawn apis (such as World and Commands).

## Solution

All `spawn` apis (`World::spawn`, `Commands:;spawn`, `ChildBuilder::spawn`, and `WorldChildBuilder::spawn`) now accept a bundle as input:

```rust
// before:
commands
  .spawn()
  .insert((A, B, C));
world
  .spawn()
  .insert((A, B, C);

// after
commands.spawn((A, B, C));
world.spawn((A, B, C));
```

All existing instances of `spawn_bundle` have been deprecated in favor of the new `spawn` api. A new `spawn_empty` has been added, replacing the old `spawn` api.  

By allowing `world.spawn(some_bundle)` to replace `world.spawn().insert(some_bundle)`, this opened the door to removing the initial entity allocation in the "empty" archetype / table done in `spawn()` (and subsequent move to the actual archetype in `.insert(some_bundle)`).

This improves spawn performance by over 10%:
![image](https://user-images.githubusercontent.com/2694663/191627587-4ab2f949-4ccd-4231-80eb-80dd4d9ad6b9.png)

To take this measurement, I added a new `world_spawn` benchmark.

Unfortunately, optimizing `Commands::spawn` is slightly less trivial, as Commands expose the Entity id of spawned entities prior to actually spawning. Doing the optimization would (naively) require assurances that the `spawn(some_bundle)` command is applied before all other commands involving the entity (which would not necessarily be true, if memory serves). Optimizing `Commands::spawn` this way does feel possible, but it will require careful thought (and maybe some additional checks), which deserves its own PR. For now, it has the same performance characteristics of the current `Commands::spawn_bundle` on main.

**Note that 99% of this PR is simple renames and refactors. The only code that needs careful scrutiny is the new `World::spawn()` impl, which is relatively straightforward, but it has some new unsafe code (which re-uses battle tested BundlerSpawner code path).** 

---

## Changelog

- All `spawn` apis (`World::spawn`, `Commands:;spawn`, `ChildBuilder::spawn`, and `WorldChildBuilder::spawn`) now accept a bundle as input
- All instances of `spawn_bundle` have been deprecated in favor of the new `spawn` api
- World and Commands now have `spawn_empty()`, which is equivalent to the old `spawn()` behavior.  

## Migration Guide

```rust
// Old (0.8):
commands
  .spawn()
  .insert_bundle((A, B, C));
// New (0.9)
commands.spawn((A, B, C));

// Old (0.8):
commands.spawn_bundle((A, B, C));
// New (0.9)
commands.spawn((A, B, C));

// Old (0.8):
let entity = commands.spawn().id();
// New (0.9)
let entity = commands.spawn_empty().id();

// Old (0.8)
let entity = world.spawn().id();
// New (0.9)
let entity = world.spawn_empty();
```
2022-09-23 19:55:54 +00:00
ira
4847f7e3ad Update codebase to use IntoIterator where possible. (#5269)
Remove unnecessary calls to `iter()`/`iter_mut()`.
Mainly updates the use of queries in our code, docs, and examples.

```rust
// From
for _ in list.iter() {
for _ in list.iter_mut() {

// To
for _ in &list {
for _ in &mut list {
```

We already enable the pedantic lint [clippy::explicit_iter_loop](https://rust-lang.github.io/rust-clippy/stable/) inside of Bevy. However, this only warns for a few known types from the standard library.

## Note for reviewers
As you can see the additions and deletions are exactly equal.
Maybe give it a quick skim to check I didn't sneak in a crypto miner, but you don't have to torture yourself by reading every line.
I already experienced enough pain making this PR :) 


Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-07-11 15:28:50 +00:00
ira
ea13f0bddf Add helper methods for rotating Transforms (#5151)
# Objective
Users often ask for help with rotations as they struggle with `Quat`s.
`Quat` is rather complex and has a ton of verbose methods.

## Solution
Add rotation helper methods to `Transform`.


Co-authored-by: devil-ira <justthecooldude@gmail.com>
2022-07-01 03:58:54 +00:00
François
73174730e4 use the default() method in examples instead of Default::default() (#4952)
# Objective

- Use the `..default()` method in examples instead of `..Default::default()`
2022-06-07 02:16:47 +00:00
Carter Anderson
f487407e07 Camera Driven Rendering (#4745)
This adds "high level camera driven rendering" to Bevy. The goal is to give users more control over what gets rendered (and where) without needing to deal with render logic. This will make scenarios like "render to texture", "multiple windows", "split screen", "2d on 3d", "3d on 2d", "pass layering", and more significantly easier. 

Here is an [example of a 2d render sandwiched between two 3d renders (each from a different perspective)](https://gist.github.com/cart/4fe56874b2e53bc5594a182fc76f4915):
![image](https://user-images.githubusercontent.com/2694663/168411086-af13dec8-0093-4a84-bdd4-d4362d850ffa.png)

Users can now spawn a camera, point it at a RenderTarget (a texture or a window), and it will "just work". 

Rendering to a second window is as simple as spawning a second camera and assigning it to a specific window id:
```rust
// main camera (main window)
commands.spawn_bundle(Camera2dBundle::default());

// second camera (other window)
commands.spawn_bundle(Camera2dBundle {
    camera: Camera {
        target: RenderTarget::Window(window_id),
        ..default()
    },
    ..default()
});
```

Rendering to a texture is as simple as pointing the camera at a texture:

```rust
commands.spawn_bundle(Camera2dBundle {
    camera: Camera {
        target: RenderTarget::Texture(image_handle),
        ..default()
    },
    ..default()
});
```

Cameras now have a "render priority", which controls the order they are drawn in. If you want to use a camera's output texture as a texture in the main pass, just set the priority to a number lower than the main pass camera (which defaults to `0`).

```rust
// main pass camera with a default priority of 0
commands.spawn_bundle(Camera2dBundle::default());

commands.spawn_bundle(Camera2dBundle {
    camera: Camera {
        target: RenderTarget::Texture(image_handle.clone()),
        priority: -1,
        ..default()
    },
    ..default()
});

commands.spawn_bundle(SpriteBundle {
    texture: image_handle,
    ..default()
})
```

Priority can also be used to layer to cameras on top of each other for the same RenderTarget. This is what "2d on top of 3d" looks like in the new system:

```rust
commands.spawn_bundle(Camera3dBundle::default());

commands.spawn_bundle(Camera2dBundle {
    camera: Camera {
        // this will render 2d entities "on top" of the default 3d camera's render
        priority: 1,
        ..default()
    },
    ..default()
});
```

There is no longer the concept of a global "active camera". Resources like `ActiveCamera<Camera2d>` and `ActiveCamera<Camera3d>` have been replaced with the camera-specific `Camera::is_active` field. This does put the onus on users to manage which cameras should be active.

Cameras are now assigned a single render graph as an "entry point", which is configured on each camera entity using the new `CameraRenderGraph` component. The old `PerspectiveCameraBundle` and `OrthographicCameraBundle` (generic on camera marker components like Camera2d and Camera3d) have been replaced by `Camera3dBundle` and `Camera2dBundle`, which set 3d and 2d default values for the `CameraRenderGraph` and projections.

```rust
// old 3d perspective camera
commands.spawn_bundle(PerspectiveCameraBundle::default())

// new 3d perspective camera
commands.spawn_bundle(Camera3dBundle::default())
```

```rust
// old 2d orthographic camera
commands.spawn_bundle(OrthographicCameraBundle::new_2d())

// new 2d orthographic camera
commands.spawn_bundle(Camera2dBundle::default())
```

```rust
// old 3d orthographic camera
commands.spawn_bundle(OrthographicCameraBundle::new_3d())

// new 3d orthographic camera
commands.spawn_bundle(Camera3dBundle {
    projection: OrthographicProjection {
        scale: 3.0,
        scaling_mode: ScalingMode::FixedVertical,
        ..default()
    }.into(),
    ..default()
})
```

Note that `Camera3dBundle` now uses a new `Projection` enum instead of hard coding the projection into the type. There are a number of motivators for this change: the render graph is now a part of the bundle, the way "generic bundles" work in the rust type system prevents nice `..default()` syntax, and changing projections at runtime is much easier with an enum (ex for editor scenarios). I'm open to discussing this choice, but I'm relatively certain we will all come to the same conclusion here. Camera2dBundle and Camera3dBundle are much clearer than being generic on marker components / using non-default constructors.

If you want to run a custom render graph on a camera, just set the `CameraRenderGraph` component:

```rust
commands.spawn_bundle(Camera3dBundle {
    camera_render_graph: CameraRenderGraph::new(some_render_graph_name),
    ..default()
})
```

Just note that if the graph requires data from specific components to work (such as `Camera3d` config, which is provided in the `Camera3dBundle`), make sure the relevant components have been added.

Speaking of using components to configure graphs / passes, there are a number of new configuration options:

```rust
commands.spawn_bundle(Camera3dBundle {
    camera_3d: Camera3d {
        // overrides the default global clear color 
        clear_color: ClearColorConfig::Custom(Color::RED),
        ..default()
    },
    ..default()
})

commands.spawn_bundle(Camera3dBundle {
    camera_3d: Camera3d {
        // disables clearing
        clear_color: ClearColorConfig::None,
        ..default()
    },
    ..default()
})
```

Expect to see more of the "graph configuration Components on Cameras" pattern in the future.

By popular demand, UI no longer requires a dedicated camera. `UiCameraBundle` has been removed. `Camera2dBundle` and `Camera3dBundle` now both default to rendering UI as part of their own render graphs. To disable UI rendering for a camera, disable it using the CameraUi component:

```rust
commands
    .spawn_bundle(Camera3dBundle::default())
    .insert(CameraUi {
        is_enabled: false,
        ..default()
    })
```

## Other Changes

* The separate clear pass has been removed. We should revisit this for things like sky rendering, but I think this PR should "keep it simple" until we're ready to properly support that (for code complexity and performance reasons). We can come up with the right design for a modular clear pass in a followup pr.
* I reorganized bevy_core_pipeline into Core2dPlugin and Core3dPlugin (and core_2d / core_3d modules). Everything is pretty much the same as before, just logically separate. I've moved relevant types (like Camera2d, Camera3d, Camera3dBundle, Camera2dBundle) into their relevant modules, which is what motivated this reorganization.
* I adapted the `scene_viewer` example (which relied on the ActiveCameras behavior) to the new system. I also refactored bits and pieces to be a bit simpler. 
* All of the examples have been ported to the new camera approach. `render_to_texture` and `multiple_windows` are now _much_ simpler. I removed `two_passes` because it is less relevant with the new approach. If someone wants to add a new "layered custom pass with CameraRenderGraph" example, that might fill a similar niche. But I don't feel much pressure to add that in this pr.
* Cameras now have `target_logical_size` and `target_physical_size` fields, which makes finding the size of a camera's render target _much_ simpler. As a result, the `Assets<Image>` and `Windows` parameters were removed from `Camera::world_to_screen`, making that operation much more ergonomic.
* Render order ambiguities between cameras with the same target and the same priority now produce a warning. This accomplishes two goals:
    1. Now that there is no "global" active camera, by default spawning two cameras will result in two renders (one covering the other). This would be a silent performance killer that would be hard to detect after the fact. By detecting ambiguities, we can provide a helpful warning when this occurs.
    2. Render order ambiguities could result in unexpected / unpredictable render results. Resolving them makes sense.

## Follow Up Work

* Per-Camera viewports, which will make it possible to render to a smaller area inside of a RenderTarget (great for something like splitscreen)
* Camera-specific MSAA config (should use the same "overriding" pattern used for ClearColor)
* Graph Based Camera Ordering: priorities are simple, but they make complicated ordering constraints harder to express. We should consider adopting a "graph based" camera ordering model with "before" and "after" relationships to other cameras (or build it "on top" of the priority system).
* Consider allowing graphs to run subgraphs from any nest level (aka a global namespace for graphs). Right now the 2d and 3d graphs each need their own UI subgraph, which feels "fine" in the short term. But being able to share subgraphs between other subgraphs seems valuable.
* Consider splitting `bevy_core_pipeline` into `bevy_core_2d` and `bevy_core_3d` packages. Theres a shared "clear color" dependency here, which would need a new home.
2022-06-02 00:12:17 +00:00
Mark Schmale
1ba7429371 Doc/module style doc blocks for examples (#4438)
# Objective

Provide a starting point for #3951, or a partial solution. 
Providing a few comment blocks to discuss, and hopefully find better one in the process. 

## Solution

Since I am pretty new to pretty much anything in this context, I figured I'd just start with a draft for some file level doc blocks. For some of them I found more relevant details (or at least things I considered interessting), for some others there is less. 

## Changelog

- Moved some existing comments from main() functions in the 2d examples to the file header level
- Wrote some more comment blocks for most other 2d examples

TODO: 
- [x] 2d/sprite_sheet, wasnt able to come up with something good yet 
- [x] all other example groups...


Also: Please let me know if the commit style is okay, or to verbose. I could certainly squash these things, or add more details if needed. 
I also hope its okay to raise this PR this early, with just a few files changed. Took me long enough and I dont wanted to let it go to waste because I lost motivation to do the whole thing. Additionally I am somewhat uncertain over the style and contents of the commets. So let me know what you thing please.
2022-05-16 13:53:20 +00:00
Mizu
9dfd4e4b08 Add examples for Transforms (#2441)
# Add Transform Examples

- Adding examples for moving/rotating entities (with its own section) to resolve #2400 

I've stumbled upon this project and been fiddling around a little. Saw the issue and thought I might just add some examples for the proposed transformations.
Mind to check if I got the gist correctly and suggest anything I can improve?
2022-03-15 05:49:49 +00:00