
# 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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/// 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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#[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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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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// 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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// 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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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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// 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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// 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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#[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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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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