# Objective
The `RenderLayers` type is never registered, making it unavailable for reflection.
## Solution
Register it in `CameraPlugin`, the same plugin that registers the related `Visibility*` types.
# Objective
- Update `wgpu` to 0.14.0, `naga` to `0.10.0`, `winit` to 0.27.4, `raw-window-handle` to 0.5.0, `ndk` to 0.7.
## Solution
---
## Changelog
### Changed
- Changed `RawWindowHandleWrapper` to `RawHandleWrapper` which wraps both `RawWindowHandle` and `RawDisplayHandle`, which satisfies the `impl HasRawWindowHandle and HasRawDisplayHandle` that `wgpu` 0.14.0 requires.
- Changed `bevy_window::WindowDescriptor`'s `cursor_locked` to `cursor_grab_mode`, change its type from `bool` to `bevy_window::CursorGrabMode`.
## Migration Guide
- Adjust usage of `bevy_window::WindowDescriptor`'s `cursor_locked` to `cursor_grab_mode`, and adjust its type from `bool` to `bevy_window::CursorGrabMode`.
# Objective
Make toggling the visibility of an entity slightly more convenient.
## Solution
Add a mutating `toggle` method to the `Visibility` component
```rust
fn my_system(mut query: Query<&mut Visibility, With<SomeMarker>>) {
let mut visibility = query.single_mut();
// before:
visibility.is_visible = !visibility.is_visible;
// after:
visibility.toggle();
}
```
## Changelog
### Added
- Added a mutating `toggle` method to the `Visibility` component
# Objective
- Trying to make it possible to do write tests that don't require a raw window handle.
- Fixes https://github.com/bevyengine/bevy/issues/6106.
## Solution
- Make the interface and type changes. Avoid accessing `None`.
---
## Changelog
- Converted `raw_window_handle` field in both `Window` and `ExtractedWindow` to `Option<RawWindowHandleWrapper>`.
- Revised accessor function `Window::raw_window_handle()` to return `Option<RawWindowHandleWrapper>`.
- Skip conditions in loops that would require a raw window handle (to create a `Surface`, for example).
## Migration Guide
`Window::raw_window_handle()` now returns `Option<RawWindowHandleWrapper>`.
Co-authored-by: targrub <62773321+targrub@users.noreply.github.com>
As suggested in #6104, it would be nice to link directly to `linux_dependencies.md` file in the panic message when running on Linux. And when not compiling for Linux, we fall back to the old message.
Signed-off-by: Lena Milizé <me@lvmn.org>
# Objective
Resolves#6104.
## Solution
Add link to `linux_dependencies.md` when compiling for Linux, and fall back to the old one when not.
…
# Objective
- Fixes Camera not being serializable due to missing registrations in core functionality.
- Fixes#6169
## Solution
- Updated Bevy_Render CameraPlugin with registrations for Option<Viewport> and then Bevy_Core CorePlugin with registrations for ReflectSerialize and ReflectDeserialize for type data Range<f32> respectively according to the solution in #6169
Co-authored-by: Noah <noahshomette@gmail.com>
# Objective
There is no Srgb support on some GPU and display protocols with `winit` (for example, Nvidia's GPUs with Wayland). Thus `TextureFormat::bevy_default()` which returns `Rgba8UnormSrgb` or `Bgra8UnormSrgb` will cause panics on such platforms. This patch will resolve this problem. Fix https://github.com/bevyengine/bevy/issues/3897.
## Solution
Make `initialize_renderer` expose `wgpu::Adapter` and `first_available_texture_format`, use the `first_available_texture_format` by default.
## Changelog
* Fixed https://github.com/bevyengine/bevy/issues/3897.
# Objective
- Reflecting `Default` is required for scripts to create `Reflect` types at runtime with no static type information.
- Reflecting `Default` on `Handle<T>` and `ComputedVisibility` should allow scripts from `bevy_mod_js_scripting` to actually spawn sprites from scratch, without needing any hand-holding from the host-game.
## Solution
- Derive `ReflectDefault` for `Handle<T>` and `ComputedVisiblity`.
---
## Changelog
> This section is optional. If this was a trivial fix, or has no externally-visible impact, you can delete this section.
- The `Default` trait is now reflected for `Handle<T>` and `ComputedVisibility`
# Objective
Add a method for getting a world space ray from a viewport position.
Opted to add a `Ray` type to `bevy_math` instead of returning a tuple of `Vec3`'s as this is clearer and easier to document
The docs on `viewport_to_world` are okay, but I'm not super happy with them.
## Changelog
* Add `Camera::viewport_to_world`
* Add `Camera::ndc_to_world`
* Add `Ray` to `bevy_math`
* Some doc tweaks
Co-authored-by: devil-ira <justthecooldude@gmail.com>
# Objective
- Currently, errors aren't logged as soon as they are found, they are logged only on the next frame. This means your shader could have an unreported error that could have been reported on the first frame.
## Solution
- Log the error as soon as they are found, don't wait until next frame
## Notes
I discovered this issue because I was simply unwrapping the `Result` from `PipelinCache::get_render_pipeline()` which caused it to fail without any explanations. Admittedly, this was a bit of a user error, I shouldn't have unwrapped that, but it seems a bit strange to wait until the next time the pipeline is processed to log the error instead of just logging it as soon as possible since we already have all the info necessary.
# Objective
The [Stageless RFC](https://github.com/bevyengine/rfcs/pull/45) involves allowing exclusive systems to be referenced and ordered relative to parallel systems. We've agreed that unifying systems under `System` is the right move.
This is an alternative to #4166 (see rationale in the comments I left there). Note that this builds on the learnings established there (and borrows some patterns).
## Solution
This unifies parallel and exclusive systems under the shared `System` trait, removing the old `ExclusiveSystem` trait / impls. This is accomplished by adding a new `ExclusiveFunctionSystem` impl similar to `FunctionSystem`. It is backed by `ExclusiveSystemParam`, which is similar to `SystemParam`. There is a new flattened out SystemContainer api (which cuts out a lot of trait and type complexity).
This means you can remove all cases of `exclusive_system()`:
```rust
// before
commands.add_system(some_system.exclusive_system());
// after
commands.add_system(some_system);
```
I've also implemented `ExclusiveSystemParam` for `&mut QueryState` and `&mut SystemState`, which makes this possible in exclusive systems:
```rust
fn some_exclusive_system(
world: &mut World,
transforms: &mut QueryState<&Transform>,
state: &mut SystemState<(Res<Time>, Query<&Player>)>,
) {
for transform in transforms.iter(world) {
println!("{transform:?}");
}
let (time, players) = state.get(world);
for player in players.iter() {
println!("{player:?}");
}
}
```
Note that "exclusive function systems" assume `&mut World` is present (and the first param). I think this is a fair assumption, given that the presence of `&mut World` is what defines the need for an exclusive system.
I added some targeted SystemParam `static` constraints, which removed the need for this:
``` rust
fn some_exclusive_system(state: &mut SystemState<(Res<'static, Time>, Query<&'static Player>)>) {}
```
## Related
- #2923
- #3001
- #3946
## Changelog
- `ExclusiveSystem` trait (and implementations) has been removed in favor of sharing the `System` trait.
- `ExclusiveFunctionSystem` and `ExclusiveSystemParam` were added, enabling flexible exclusive function systems
- `&mut SystemState` and `&mut QueryState` now implement `ExclusiveSystemParam`
- Exclusive and parallel System configuration is now done via a unified `SystemDescriptor`, `IntoSystemDescriptor`, and `SystemContainer` api.
## Migration Guide
Calling `.exclusive_system()` is no longer required (or supported) for converting exclusive system functions to exclusive systems:
```rust
// Old (0.8)
app.add_system(some_exclusive_system.exclusive_system());
// New (0.9)
app.add_system(some_exclusive_system);
```
Converting "normal" parallel systems to exclusive systems is done by calling the exclusive ordering apis:
```rust
// Old (0.8)
app.add_system(some_system.exclusive_system().at_end());
// New (0.9)
app.add_system(some_system.at_end());
```
Query state in exclusive systems can now be cached via ExclusiveSystemParams, which should be preferred for clarity and performance reasons:
```rust
// Old (0.8)
fn some_system(world: &mut World) {
let mut transforms = world.query::<&Transform>();
for transform in transforms.iter(world) {
}
}
// New (0.9)
fn some_system(world: &mut World, transforms: &mut QueryState<&Transform>) {
for transform in transforms.iter(world) {
}
}
```
# 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%:
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();
```
# Objective
- Reconfigure surface after present mode changes. It seems that this is not done currently at runtime. It's pretty common for games to change such graphical settings at runtime.
- Fixes present mode issue in #5111
## Solution
- Exactly like resolution change gets tracked when extracting window, do the same for present mode.
Additionally, I added present mode (vsync) toggling to window settings example.
# Objective
Take advantage of the "impl Bundle for Component" changes in #2975 / add the follow up changes discussed there.
## Solution
- Change `insert` and `remove` to accept a Bundle instead of a Component (for both Commands and World)
- Deprecate `insert_bundle`, `remove_bundle`, and `remove_bundle_intersection`
- Add `remove_intersection`
---
## Changelog
- Change `insert` and `remove` now accept a Bundle instead of a Component (for both Commands and World)
- `insert_bundle` and `remove_bundle` are deprecated
## Migration Guide
Replace `insert_bundle` with `insert`:
```rust
// Old (0.8)
commands.spawn().insert_bundle(SomeBundle::default());
// New (0.9)
commands.spawn().insert(SomeBundle::default());
```
Replace `remove_bundle` with `remove`:
```rust
// Old (0.8)
commands.entity(some_entity).remove_bundle::<SomeBundle>();
// New (0.9)
commands.entity(some_entity).remove::<SomeBundle>();
```
Replace `remove_bundle_intersection` with `remove_intersection`:
```rust
// Old (0.8)
world.entity_mut(some_entity).remove_bundle_intersection::<SomeBundle>();
// New (0.9)
world.entity_mut(some_entity).remove_intersection::<SomeBundle>();
```
Consider consolidating as many operations as possible to improve ergonomics and cut down on archetype moves:
```rust
// Old (0.8)
commands.spawn()
.insert_bundle(SomeBundle::default())
.insert(SomeComponent);
// New (0.9) - Option 1
commands.spawn().insert((
SomeBundle::default(),
SomeComponent,
))
// New (0.9) - Option 2
commands.spawn_bundle((
SomeBundle::default(),
SomeComponent,
))
```
## Next Steps
Consider changing `spawn` to accept a bundle and deprecate `spawn_bundle`.
# Objective
Implement `IntoIterator` for `&Extract<P>` if the system parameter it wraps implements `IntoIterator`.
Enables the use of `IntoIterator` with an extracted query.
Co-authored-by: devil-ira <justthecooldude@gmail.com>
# Objective
A common pitfall since 0.8 is the requirement on `ComputedVisibility`
being present on all ancestors of an entity that itself has
`ComputedVisibility`, without which, the entity becomes invisible.
I myself hit the issue and got very confused, and saw a few people hit
it as well, so it makes sense to provide a hint of what to do when such
a situation is encountered.
- Fixes#5849
- Closes#5616
- Closes#2277
- Closes#5081
## Solution
We now check that all entities with both a `Parent` and a
`ComputedVisibility` component have parents that themselves have a
`ComputedVisibility` component.
Note that the warning is only printed once.
We also add a similar warning to `GlobalTransform`.
This only emits a warning. Because sometimes it could be an intended
behavior.
Alternatives:
- Do nothing and keep repeating to newcomers how to avoid recurring
pitfalls
- Make the transform and visibility propagation tolerant to missing
components (#5616)
- Probably archetype invariants, though the current draft would not
allow detecting that kind of errors
---
## Changelog
- Add a warning when encountering dubious component hierarchy structure
Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
# Objective
fixes#5946
## Solution
adjust cluster index calculation for viewport origin.
from reading point 2 of the rasterization algorithm description in https://gpuweb.github.io/gpuweb/#rasterization, it looks like framebuffer space (and so @bulitin(position)) is not meant to be adjusted for viewport origin, so we need to subtract that to get the right cluster index.
- add viewport origin to rust `ExtractedView` and wgsl `View` structs
- subtract from frag coord for cluster index calculation
# Objective
Currently some TextureFormats are not supported by the Image type.
The `TextureFormat::Rg16Unorm` format is useful for storing minmax heightmaps.
Similar to #5249 I now additionally require image to support the dual channel variant.
## Solution
Added `TextureFormat::Rg16Unorm` support to Image.
Additionally this PR derives `Resource` for `SpecializedComputePipelines`, because for some reason this was missing.
All other special pipelines do derive `Resource` already.
Co-authored-by: Kurt Kühnert <51823519+Ku95@users.noreply.github.com>
## Solution
Exposes the image <-> "texture" as methods on `Image`.
## Extra
I'm wondering if `image_texture_conversion.rs` should be renamed to `image_conversion.rs`. That or the file be deleted altogether in favour of putting the code alongside the rest of the `Image` impl. Its kind-of weird to refer to the `Image` as a texture.
Also `Image::convert` is a public method so I didn't want to edit its signature, but it might be nice to have the function consume the image instead of just passing a reference to it because it would eliminate a clone.
## Changelog
> Rename `image_to_texture` to `Image::from_dynamic`
> Rename `texture_to_image` to `Image::try_into_dynamic`
> `Image::try_into_dynamic` now returns a `Result` (this is to make it easier for users who didn't read that only a few conversions are supported to figure it out.)
# Objective
Document most of the public items of the `bevy_render::camera` module and its
sub-modules.
## Solution
Add docs to most public items. Follow-up from #3447.
# Objective
Document `PipelineCache` and a few other related types.
## Solution
Add documenting comments to `PipelineCache` and a few other related
types in the same file.
# Objective
- In WASM, creating a pipeline can easily take 2 seconds, freezing the game while doing so
- Preloading pipelines can be done during a "loading" state, but it is not trivial to know which pipeline to preload, or when it's done
## Solution
- Add a log with shaders being loaded and their shader defs
- add a function on `PipelineCache` to return the number of ready pipelines
# Objective
Since `identity` is a const fn that takes no arguments it seems logical to make it an associated constant.
This is also more in line with types from glam (eg. `Quat::IDENTITY`).
## Migration Guide
The method `identity()` on `Transform`, `GlobalTransform` and `TransformBundle` has been deprecated.
Use the associated constant `IDENTITY` instead.
Co-authored-by: devil-ira <justthecooldude@gmail.com>
# Objective
- While generating https://github.com/jakobhellermann/bevy_reflect_ts_type_export/blob/main/generated/types.ts, I noticed that some types that implement `Reflect` did not register themselves
- `Viewport` isn't reflect but can be (there's a TODO)
## Solution
- register all reflected types
- derive `Reflect` for `Viewport`
## Changelog
- more types are not registered in the type registry
- remove `Serialize`, `Deserialize` impls from `Viewport`
I also decided to remove the `Serialize, Deserialize` from the `Viewport`, since they were (AFAIK) only used for reflection, which now is done without serde. So this is technically a breaking change for people who relied on that impl directly.
Personally I don't think that every bevy type should implement `Serialize, Deserialize`, as that would lead to a ton of code generation that mostly isn't necessary because we can do the same with `Reflect`, but if this is deemed controversial I can remove it from this PR.
## Migration Guide
- `KeyCode` now implements `Reflect` not as `reflect_value`, but with proper struct reflection. The `Serialize` and `Deserialize` impls were removed, now that they are no longer required for scene serialization.
# Objective
Fix a nasty system ordering bug between `update_frusta` and `camera_system` that lead to incorrect frustum s, leading to excessive culling and extremely hard-to-debug visual glitches
## Solution
- add explicit system ordering
Probably a copy-paste error, but `Add<Color>` and `AddAssign<Color>` should use `rhs.as_hlsa_f32()` instead of `rhs.as_linear_rgba_f32()` when the LHS is a `Color::Hsla`. Fixes#5543.
Co-authored-by: Verte <105466627+vertesians@users.noreply.github.com>
# Objective
The reflection impls on `Option<T>` have the bound `T: Reflect + Clone`. This means that using `FromReflect` requires `Clone` even though we can normally get away with just `FromReflect`.
## Solution
Update the bounds on `Option<T>` to match that of `Vec<T>`, where `T: FromReflect`.
This helps remove a `Clone` implementation that may be undesired but added for the sole purpose of getting the code to compile.
---
## Changelog
* Reflection on `Option<T>` now has `T` bound by `FromReflect` rather than `Reflect + Clone`
* Added a `FromReflect` impl for `Instant`
## Migration Guide
If using `Option<T>` with Bevy's reflection API, `T` now needs to implement `FromReflect` rather than just `Clone`. This can be achieved easily by simply deriving `FromReflect`:
```rust
// OLD
#[derive(Reflect, Clone)]
struct Foo;
let reflected: Box<dyn Reflect> = Box::new(Some(Foo));
// NEW
#[derive(Reflect, FromReflect)]
struct Foo;
let reflected: Box<dyn Reflect> = Box::new(Some(Foo));
```
> Note: You can still derive `Clone`, but it's not required in order to compile.
# Objective
Rust 1.63 resolved [an issue](https://github.com/rust-lang/rust/issues/83701) that prevents you from combining explicit generic arguments with `impl Trait` arguments.
Now, we no longer need to use dynamic dispatch to work around this.
## Migration Guide
The methods `Schedule::get_stage` and `get_stage_mut` now accept `impl StageLabel` instead of `&dyn StageLabel`.
### Before
```rust
let stage = schedule.get_stage_mut::<SystemStage>(&MyLabel)?;
```
### After
```rust
let stage = schedule.get_stage_mut::<SystemStage>(MyLabel)?;
```
# Objective
When an invalid attribute is inserted and the LogPlugin is not enabled the full error is not printed which means makes it hard to diagnose.
## Solution
- Always print the full message in the panic.
## Notes
I originally had a separate error log because I wanted to make it clearer for users, but this is probably causing more issues than necessary.
# Objective
Remove unused `enum DepthCalculation` and its usages. This was used to compute visible entities in the [old renderer](db665b96c0/crates/bevy_render/src/camera/visible_entities.rs), but is now unused.
## Solution
`sed 's/DepthCalculation//g'`
---
## Changelog
### Changed
Removed `bevy_render:📷:DepthCalculation`.
## Migration Guide
Remove references to `bevy_render:📷:DepthCalculation`, such as `use bevy_render:📷:DepthCalculation`. Remove `depth_calculation` fields from Projections.
# Objective
`ShaderData` is marked as public, but is an internal type only used by one other
internal type, so it should be made private.
## Solution
`ShaderData` is only used in `ShaderCache`, and the latter is private,
so there is no need to make the former public. This change removes the
`pub` keyword from `ShaderData`, hidding it as the implementation detail
it is.
Split from #5600
# Objective
- I often have UI nodes that are completely transparent and just for organisation
- Don't render them
- I doesn't bring a lot of improvements, but it doesn't add a lot of complexity either
*This PR description is an edited copy of #5007, written by @alice-i-cecile.*
# Objective
Follow-up to https://github.com/bevyengine/bevy/pull/2254. The `Resource` trait currently has a blanket implementation for all types that meet its bounds.
While ergonomic, this results in several drawbacks:
* it is possible to make confusing, silent mistakes such as inserting a function pointer (Foo) rather than a value (Foo::Bar) as a resource
* it is challenging to discover if a type is intended to be used as a resource
* we cannot later add customization options (see the [RFC](https://github.com/bevyengine/rfcs/blob/main/rfcs/27-derive-component.md) for the equivalent choice for Component).
* dependencies can use the same Rust type as a resource in invisibly conflicting ways
* raw Rust types used as resources cannot preserve privacy appropriately, as anyone able to access that type can read and write to internal values
* we cannot capture a definitive list of possible resources to display to users in an editor
## Notes to reviewers
* Review this commit-by-commit; there's effectively no back-tracking and there's a lot of churn in some of these commits.
*ira: My commits are not as well organized :')*
* I've relaxed the bound on Local to Send + Sync + 'static: I don't think these concerns apply there, so this can keep things simple. Storing e.g. a u32 in a Local is fine, because there's a variable name attached explaining what it does.
* I think this is a bad place for the Resource trait to live, but I've left it in place to make reviewing easier. IMO that's best tackled with https://github.com/bevyengine/bevy/issues/4981.
## Changelog
`Resource` is no longer automatically implemented for all matching types. Instead, use the new `#[derive(Resource)]` macro.
## Migration Guide
Add `#[derive(Resource)]` to all types you are using as a resource.
If you are using a third party type as a resource, wrap it in a tuple struct to bypass orphan rules. Consider deriving `Deref` and `DerefMut` to improve ergonomics.
`ClearColor` no longer implements `Component`. Using `ClearColor` as a component in 0.8 did nothing.
Use the `ClearColorConfig` in the `Camera3d` and `Camera2d` components instead.
Co-authored-by: Alice <alice.i.cecile@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: devil-ira <justthecooldude@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
In Bevy 0.8, the default filter mode was changed to linear (#4465). I believe this is a sensible default, but it's also very common to want to use point filtering (e.g. for pixel art games).
## Solution
I am proposing including `bevy_render::texture::ImageSettings` in the Bevy prelude so it is more ergonomic to change the filtering in such cases.
---
## Changelog
### Added
- Added `bevy_render::texture::ImageSettings` to prelude.
> In draft until #4761 is merged. See the relevant commits [here](a85fe94a18).
---
# Objective
Update enums across Bevy to use the new enum reflection and get rid of `#[reflect_value(...)]` usages.
## Solution
Find and replace all[^1] instances of `#[reflect_value(...)]` on enum types.
---
## Changelog
- Updated all[^1] reflected enums to implement `Enum` (i.e. they are no longer `ReflectRef::Value`)
## Migration Guide
Bevy-defined enums have been updated to implement `Enum` and are not considered value types (`ReflectRef::Value`) anymore. This means that their serialized representations will need to be updated. For example, given the Bevy enum:
```rust
pub enum ScalingMode {
None,
WindowSize,
Auto { min_width: f32, min_height: f32 },
FixedVertical(f32),
FixedHorizontal(f32),
}
```
You will need to update the serialized versions accordingly.
```js
// OLD FORMAT
{
"type": "bevy_render:📷:projection::ScalingMode",
"value": FixedHorizontal(720),
},
// NEW FORMAT
{
"type": "bevy_render:📷:projection::ScalingMode",
"enum": {
"variant": "FixedHorizontal",
"tuple": [
{
"type": "f32",
"value": 720,
},
],
},
},
```
This may also have other smaller implications (such as `Debug` representation), but serialization is probably the most prominent.
[^1]: All enums except `HandleId` as neither `Uuid` nor `AssetPathId` implement the reflection traits
# Objective
> This is a revival of #1347. Credit for the original PR should go to @Davier.
Currently, enums are treated as `ReflectRef::Value` types by `bevy_reflect`. Obviously, there needs to be better a better representation for enums using the reflection API.
## Solution
Based on prior work from @Davier, an `Enum` trait has been added as well as the ability to automatically implement it via the `Reflect` derive macro. This allows enums to be expressed dynamically:
```rust
#[derive(Reflect)]
enum Foo {
A,
B(usize),
C { value: f32 },
}
let mut foo = Foo::B(123);
assert_eq!("B", foo.variant_name());
assert_eq!(1, foo.field_len());
let new_value = DynamicEnum::from(Foo::C { value: 1.23 });
foo.apply(&new_value);
assert_eq!(Foo::C{value: 1.23}, foo);
```
### Features
#### Derive Macro
Use the `#[derive(Reflect)]` macro to automatically implement the `Enum` trait for enum definitions. Optionally, you can use `#[reflect(ignore)]` with both variants and variant fields, just like you can with structs. These ignored items will not be considered as part of the reflection and cannot be accessed via reflection.
```rust
#[derive(Reflect)]
enum TestEnum {
A,
// Uncomment to ignore all of `B`
// #[reflect(ignore)]
B(usize),
C {
// Uncomment to ignore only field `foo` of `C`
// #[reflect(ignore)]
foo: f32,
bar: bool,
},
}
```
#### Dynamic Enums
Enums may be created/represented dynamically via the `DynamicEnum` struct. The main purpose of this struct is to allow enums to be deserialized into a partial state and to allow dynamic patching. In order to ensure conversion from a `DynamicEnum` to a concrete enum type goes smoothly, be sure to add `FromReflect` to your derive macro.
```rust
let mut value = TestEnum::A;
// Create from a concrete instance
let dyn_enum = DynamicEnum::from(TestEnum::B(123));
value.apply(&dyn_enum);
assert_eq!(TestEnum::B(123), value);
// Create a purely dynamic instance
let dyn_enum = DynamicEnum::new("TestEnum", "A", ());
value.apply(&dyn_enum);
assert_eq!(TestEnum::A, value);
```
#### Variants
An enum value is always represented as one of its variants— never the enum in its entirety.
```rust
let value = TestEnum::A;
assert_eq!("A", value.variant_name());
// Since we are using the `A` variant, we cannot also be the `B` variant
assert_ne!("B", value.variant_name());
```
All variant types are representable within the `Enum` trait: unit, struct, and tuple.
You can get the current type like:
```rust
match value.variant_type() {
VariantType::Unit => println!("A unit variant!"),
VariantType::Struct => println!("A struct variant!"),
VariantType::Tuple => println!("A tuple variant!"),
}
```
> Notice that they don't contain any values representing the fields. These are purely tags.
If a variant has them, you can access the fields as well:
```rust
let mut value = TestEnum::C {
foo: 1.23,
bar: false
};
// Read/write specific fields
*value.field_mut("bar").unwrap() = true;
// Iterate over the entire collection of fields
for field in value.iter_fields() {
println!("{} = {:?}", field.name(), field.value());
}
```
#### Variant Swapping
It might seem odd to group all variant types under a single trait (why allow `iter_fields` on a unit variant?), but the reason this was done ~~is to easily allow *variant swapping*.~~ As I was recently drafting up the **Design Decisions** section, I discovered that other solutions could have been made to work with variant swapping. So while there are reasons to keep the all-in-one approach, variant swapping is _not_ one of them.
```rust
let mut value: Box<dyn Enum> = Box::new(TestEnum::A);
value.set(Box::new(TestEnum::B(123))).unwrap();
```
#### Serialization
Enums can be serialized and deserialized via reflection without needing to implement `Serialize` or `Deserialize` themselves (which can save thousands of lines of generated code). Below are the ways an enum can be serialized.
> Note, like the rest of reflection-based serialization, the order of the keys in these representations is important!
##### Unit
```json
{
"type": "my_crate::TestEnum",
"enum": {
"variant": "A"
}
}
```
##### Tuple
```json
{
"type": "my_crate::TestEnum",
"enum": {
"variant": "B",
"tuple": [
{
"type": "usize",
"value": 123
}
]
}
}
```
<details>
<summary>Effects on Option</summary>
This ends up making `Option` look a little ugly:
```json
{
"type": "core::option::Option<usize>",
"enum": {
"variant": "Some",
"tuple": [
{
"type": "usize",
"value": 123
}
]
}
}
```
</details>
##### Struct
```json
{
"type": "my_crate::TestEnum",
"enum": {
"variant": "C",
"struct": {
"foo": {
"type": "f32",
"value": 1.23
},
"bar": {
"type": "bool",
"value": false
}
}
}
}
```
## Design Decisions
<details>
<summary><strong>View Section</strong></summary>
This section is here to provide some context for why certain decisions were made for this PR, alternatives that could have been used instead, and what could be improved upon in the future.
### Variant Representation
One of the biggest decisions was to decide on how to represent variants. The current design uses a "all-in-one" design where unit, tuple, and struct variants are all simultaneously represented by the `Enum` trait. This is not the only way it could have been done, though.
#### Alternatives
##### 1. Variant Traits
One way of representing variants would be to define traits for each variant, implementing them whenever an enum featured at least one instance of them. This would allow us to define variants like:
```rust
pub trait Enum: Reflect {
fn variant(&self) -> Variant;
}
pub enum Variant<'a> {
Unit,
Tuple(&'a dyn TupleVariant),
Struct(&'a dyn StructVariant),
}
pub trait TupleVariant {
fn field_len(&self) -> usize;
// ...
}
```
And then do things like:
```rust
fn get_tuple_len(foo: &dyn Enum) -> usize {
match foo.variant() {
Variant::Tuple(tuple) => tuple.field_len(),
_ => panic!("not a tuple variant!")
}
}
```
The reason this PR does not go with this approach is because of the fact that variants are not separate types. In other words, we cannot implement traits on specific variants— these cover the *entire* enum. This means we offer an easy footgun:
```rust
let foo: Option<i32> = None;
let my_enum = Box::new(foo) as Box<dyn TupleVariant>;
```
Here, `my_enum` contains `foo`, which is a unit variant. However, since we need to implement `TupleVariant` for `Option` as a whole, it's possible to perform such a cast. This is obviously wrong, but could easily go unnoticed. So unfortunately, this makes it not a good candidate for representing variants.
##### 2. Variant Structs
To get around the issue of traits necessarily needing to apply to both the enum and its variants, we could instead use structs that are created on a per-variant basis. This was also considered but was ultimately [[removed](71d27ab3c6) due to concerns about allocations.
Each variant struct would probably look something like:
```rust
pub trait Enum: Reflect {
fn variant_mut(&self) -> VariantMut;
}
pub enum VariantMut<'a> {
Unit,
Tuple(TupleVariantMut),
Struct(StructVariantMut),
}
struct StructVariantMut<'a> {
fields: Vec<&'a mut dyn Reflect>,
field_indices: HashMap<Cow<'static, str>, usize>
}
```
This allows us to isolate struct variants into their own defined struct and define methods specifically for their use. It also prevents users from casting to it since it's not a trait. However, this is not an optimal solution. Both `field_indices` and `fields` will require an allocation (remember, a `Box<[T]>` still requires a `Vec<T>` in order to be constructed). This *might* be a problem if called frequently enough.
##### 3. Generated Structs
The original design, implemented by @Davier, instead generates structs specific for each variant. So if we had a variant path like `Foo::Bar`, we'd generate a struct named `FooBarWrapper`. This would be newtyped around the original enum and forward tuple or struct methods to the enum with the chosen variant.
Because it involved using the `Tuple` and `Struct` traits (which are also both bound on `Reflect`), this meant a bit more code had to be generated. For a single struct variant with one field, the generated code amounted to ~110LoC. However, each new field added to that variant only added ~6 more LoC.
In order to work properly, the enum had to be transmuted to the generated struct:
```rust
fn variant(&self) -> crate::EnumVariant<'_> {
match self {
Foo::Bar {value: i32} => {
let wrapper_ref = unsafe {
std::mem::transmute::<&Self, &FooBarWrapper>(self)
};
crate::EnumVariant::Struct(wrapper_ref as &dyn crate::Struct)
}
}
}
```
This works because `FooBarWrapper` is defined as `repr(transparent)`.
Out of all the alternatives, this would probably be the one most likely to be used again in the future. The reasons for why this PR did not continue to use it was because:
* To reduce generated code (which would hopefully speed up compile times)
* To avoid cluttering the code with generated structs not visible to the user
* To keep bevy_reflect simple and extensible (these generated structs act as proxies and might not play well with current or future systems)
* To avoid additional unsafe blocks
* My own misunderstanding of @Davier's code
That last point is obviously on me. I misjudged the code to be too unsafe and unable to handle variant swapping (which it probably could) when I was rebasing it. Looking over it again when writing up this whole section, I see that it was actually a pretty clever way of handling variant representation.
#### Benefits of All-in-One
As stated before, the current implementation uses an all-in-one approach. All variants are capable of containing fields as far as `Enum` is concerned. This provides a few benefits that the alternatives do not (reduced indirection, safer code, etc.).
The biggest benefit, though, is direct field access. Rather than forcing users to have to go through pattern matching, we grant direct access to the fields contained by the current variant. The reason we can do this is because all of the pattern matching happens internally. Getting the field at index `2` will automatically return `Some(...)` for the current variant if it has a field at that index or `None` if it doesn't (or can't).
This could be useful for scenarios where the variant has already been verified or just set/swapped (or even where the type of variant doesn't matter):
```rust
let dyn_enum: &mut dyn Enum = &mut Foo::Bar {value: 123};
// We know it's the `Bar` variant
let field = dyn_enum.field("value").unwrap();
```
Reflection is not a type-safe abstraction— almost every return value is wrapped in `Option<...>`. There are plenty of places to check and recheck that a value is what Reflect says it is. Forcing users to have to go through `match` each time they want to access a field might just be an extra step among dozens of other verification processes.
Some might disagree, but ultimately, my view is that the benefit here is an improvement to the ergonomics and usability of reflected enums.
</details>
---
## Changelog
### Added
* Added `Enum` trait
* Added `Enum` impl to `Reflect` derive macro
* Added `DynamicEnum` struct
* Added `DynamicVariant`
* Added `EnumInfo`
* Added `VariantInfo`
* Added `StructVariantInfo`
* Added `TupleVariantInfo`
* Added `UnitVariantInfo`
* Added serializtion/deserialization support for enums
* Added `EnumSerializer`
* Added `VariantType`
* Added `VariantFieldIter`
* Added `VariantField`
* Added `enum_partial_eq(...)`
* Added `enum_hash(...)`
### Changed
* `Option<T>` now implements `Enum`
* `bevy_window` now depends on `bevy_reflect`
* Implemented `Reflect` and `FromReflect` for `WindowId`
* Derive `FromReflect` on `PerspectiveProjection`
* Derive `FromReflect` on `OrthographicProjection`
* Derive `FromReflect` on `WindowOrigin`
* Derive `FromReflect` on `ScalingMode`
* Derive `FromReflect` on `DepthCalculation`
## Migration Guide
* Enums no longer need to be treated as values and usages of `#[reflect_value(...)]` can be removed or replaced by `#[reflect(...)]`
* Enums (including `Option<T>`) now take a different format when serializing. The format is described above, but this may cause issues for existing scenes that make use of enums.
---
Also shout out to @nicopap for helping clean up some of the code here! It's a big feature so help like this is really appreciated!
Co-authored-by: Gino Valente <gino.valente.code@gmail.com>
