 1efc762924
			
		
	
	
		1efc762924
		
			
		
	
	
	
	
		
			
			# Objective
- Introduce a stable alternative to
[`std::any::type_name`](https://doc.rust-lang.org/std/any/fn.type_name.html).
- Rewrite of #5805 with heavy inspiration in design.
- On the path to #5830.
- Part of solving #3327.
## Solution
- Add a `TypePath` trait for static stable type path/name information.
- Add a `TypePath` derive macro.
- Add a `impl_type_path` macro for implementing internal and foreign
types in `bevy_reflect`.
---
## Changelog
- Added `TypePath` trait.
- Added `DynamicTypePath` trait and `get_type_path` method to `Reflect`.
- Added a `TypePath` derive macro.
- Added a `bevy_reflect::impl_type_path` for implementing `TypePath` on
internal and foreign types in `bevy_reflect`.
- Changed `bevy_reflect::utility::(Non)GenericTypeInfoCell` to
`(Non)GenericTypedCell<T>` which allows us to be generic over both
`TypeInfo` and `TypePath`.
- `TypePath` is now a supertrait of `Asset`, `Material` and
`Material2d`.
- `impl_reflect_struct` needs a `#[type_path = "..."]` attribute to be
specified.
- `impl_reflect_value` needs to either specify path starting with a
double colon (`::core::option::Option`) or an `in my_crate::foo`
declaration.
- Added `bevy_reflect_derive::ReflectTypePath`.
- Most uses of `Ident` in `bevy_reflect_derive` changed to use
`ReflectTypePath`.
## Migration Guide
- Implementors of `Asset`, `Material` and `Material2d` now also need to
derive `TypePath`.
- Manual implementors of `Reflect` will need to implement the new
`get_type_path` method.
## Open Questions
- [x] ~This PR currently does not migrate any usages of
`std::any::type_name` to use `bevy_reflect::TypePath` to ease the review
process. Should it?~ Migration will be left to a follow-up PR.
- [ ] This PR adds a lot of `#[derive(TypePath)]` and `T: TypePath` to
satisfy new bounds, mostly when deriving `TypeUuid`. Should we make
`TypePath` a supertrait of `TypeUuid`? [Should we remove `TypeUuid` in
favour of
`TypePath`?](2afbd85532 (r961067892))
		
	
			
		
			
				
	
	
		
			105 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			105 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
| use bevy::{
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|     asset::LoadState,
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|     prelude::*,
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|     reflect::{TypePath, TypeUuid},
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|     render::render_resource::{AsBindGroup, ShaderRef},
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| };
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| 
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| /// This example illustrates how to create a texture for use with a `texture_2d_array<f32>` shader
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| /// uniform variable.
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| fn main() {
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|     App::new()
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|         .add_plugins(DefaultPlugins)
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|         .add_plugin(MaterialPlugin::<ArrayTextureMaterial>::default())
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|         .add_systems(Startup, setup)
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|         .add_systems(Update, create_array_texture)
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|         .run();
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| }
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| 
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| #[derive(Resource)]
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| struct LoadingTexture {
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|     is_loaded: bool,
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|     handle: Handle<Image>,
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| }
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| 
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| fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
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|     // Start loading the texture.
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|     commands.insert_resource(LoadingTexture {
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|         is_loaded: false,
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|         handle: asset_server.load("textures/array_texture.png"),
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|     });
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| 
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|     // light
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|     commands.spawn(PointLightBundle {
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|         point_light: PointLight {
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|             intensity: 3000.0,
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|             ..Default::default()
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|         },
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|         transform: Transform::from_xyz(-3.0, 2.0, -1.0),
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|         ..Default::default()
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|     });
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|     commands.spawn(PointLightBundle {
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|         point_light: PointLight {
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|             intensity: 3000.0,
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|             ..Default::default()
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|         },
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|         transform: Transform::from_xyz(3.0, 2.0, 1.0),
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|         ..Default::default()
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|     });
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| 
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|     // camera
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|     commands.spawn(Camera3dBundle {
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|         transform: Transform::from_xyz(5.0, 5.0, 5.0).looking_at(Vec3::new(1.5, 0.0, 0.0), Vec3::Y),
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|         ..Default::default()
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|     });
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| }
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| 
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| fn create_array_texture(
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|     mut commands: Commands,
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|     asset_server: Res<AssetServer>,
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|     mut loading_texture: ResMut<LoadingTexture>,
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|     mut images: ResMut<Assets<Image>>,
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|     mut meshes: ResMut<Assets<Mesh>>,
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|     mut materials: ResMut<Assets<ArrayTextureMaterial>>,
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| ) {
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|     if loading_texture.is_loaded
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|         || asset_server.get_load_state(loading_texture.handle.clone()) != LoadState::Loaded
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|     {
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|         return;
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|     }
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|     loading_texture.is_loaded = true;
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|     let image = images.get_mut(&loading_texture.handle).unwrap();
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| 
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|     // Create a new array texture asset from the loaded texture.
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|     let array_layers = 4;
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|     image.reinterpret_stacked_2d_as_array(array_layers);
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| 
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|     // Spawn some cubes using the array texture
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|     let mesh_handle = meshes.add(Mesh::from(shape::Cube { size: 1.0 }));
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|     let material_handle = materials.add(ArrayTextureMaterial {
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|         array_texture: loading_texture.handle.clone(),
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|     });
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|     for x in -5..=5 {
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|         commands.spawn(MaterialMeshBundle {
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|             mesh: mesh_handle.clone(),
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|             material: material_handle.clone(),
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|             transform: Transform::from_xyz(x as f32 + 0.5, 0.0, 0.0),
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|             ..Default::default()
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|         });
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|     }
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| }
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| 
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| #[derive(AsBindGroup, Debug, Clone, TypeUuid, TypePath)]
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| #[uuid = "9c5a0ddf-1eaf-41b4-9832-ed736fd26af3"]
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| struct ArrayTextureMaterial {
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|     #[texture(0, dimension = "2d_array")]
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|     #[sampler(1)]
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|     array_texture: Handle<Image>,
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| }
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| 
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| impl Material for ArrayTextureMaterial {
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|     fn fragment_shader() -> ShaderRef {
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|         "shaders/array_texture.wgsl".into()
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|     }
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| }
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