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))
103 lines
3.0 KiB
Rust
103 lines
3.0 KiB
Rust
//! A shader that uses "shaders defs", which selectively toggle parts of a shader.
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use bevy::{
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pbr::{MaterialPipeline, MaterialPipelineKey},
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prelude::*,
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reflect::{TypePath, TypeUuid},
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render::{
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mesh::MeshVertexBufferLayout,
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render_resource::{
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AsBindGroup, RenderPipelineDescriptor, ShaderRef, SpecializedMeshPipelineError,
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},
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},
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};
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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::<CustomMaterial>::default())
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.add_systems(Startup, setup)
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.run();
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}
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/// set up a simple 3D scene
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fn setup(
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mut commands: Commands,
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mut meshes: ResMut<Assets<Mesh>>,
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mut materials: ResMut<Assets<CustomMaterial>>,
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) {
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// blue cube
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commands.spawn(MaterialMeshBundle {
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mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
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transform: Transform::from_xyz(-1.0, 0.5, 0.0),
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material: materials.add(CustomMaterial {
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color: Color::BLUE,
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is_red: false,
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}),
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..default()
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});
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// red cube (with green color overridden by the IS_RED "shader def")
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commands.spawn(MaterialMeshBundle {
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mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
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transform: Transform::from_xyz(1.0, 0.5, 0.0),
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material: materials.add(CustomMaterial {
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color: Color::GREEN,
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is_red: true,
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}),
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..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(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
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..default()
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});
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}
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impl Material for CustomMaterial {
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fn fragment_shader() -> ShaderRef {
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"shaders/shader_defs.wgsl".into()
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}
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fn specialize(
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_pipeline: &MaterialPipeline<Self>,
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descriptor: &mut RenderPipelineDescriptor,
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_layout: &MeshVertexBufferLayout,
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key: MaterialPipelineKey<Self>,
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) -> Result<(), SpecializedMeshPipelineError> {
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if key.bind_group_data.is_red {
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let fragment = descriptor.fragment.as_mut().unwrap();
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fragment.shader_defs.push("IS_RED".into());
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}
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Ok(())
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}
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}
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// This is the struct that will be passed to your shader
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#[derive(AsBindGroup, TypeUuid, TypePath, Debug, Clone)]
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#[uuid = "f690fdae-d598-45ab-8225-97e2a3f056e0"]
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#[bind_group_data(CustomMaterialKey)]
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pub struct CustomMaterial {
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#[uniform(0)]
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color: Color,
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is_red: bool,
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}
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// This key is used to identify a specific permutation of this material pipeline.
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// In this case, we specialize on whether or not to configure the "IS_RED" shader def.
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// Specialization keys should be kept as small / cheap to hash as possible,
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// as they will be used to look up the pipeline for each drawn entity with this material type.
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#[derive(Eq, PartialEq, Hash, Clone)]
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pub struct CustomMaterialKey {
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is_red: bool,
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}
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impl From<&CustomMaterial> for CustomMaterialKey {
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fn from(material: &CustomMaterial) -> Self {
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Self {
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is_red: material.is_red,
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}
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}
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}
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