bevy/examples/shader/shader_material_glsl.rs
radiish 1efc762924
reflect: stable type path v2 (#7184)
# 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))
2023-06-05 20:31:20 +00:00

90 lines
2.8 KiB
Rust

//! A shader that uses the GLSL shading language.
use bevy::{
pbr::{MaterialPipeline, MaterialPipelineKey},
prelude::*,
reflect::{TypePath, TypeUuid},
render::{
mesh::MeshVertexBufferLayout,
render_resource::{
AsBindGroup, RenderPipelineDescriptor, ShaderRef, SpecializedMeshPipelineError,
},
},
};
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_plugin(MaterialPlugin::<CustomMaterial>::default())
.add_systems(Startup, setup)
.run();
}
/// set up a simple 3D scene
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<CustomMaterial>>,
asset_server: Res<AssetServer>,
) {
// cube
commands.spawn(MaterialMeshBundle {
mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
transform: Transform::from_xyz(0.0, 0.5, 0.0),
material: materials.add(CustomMaterial {
color: Color::BLUE,
color_texture: Some(asset_server.load("branding/icon.png")),
alpha_mode: AlphaMode::Blend,
}),
..default()
});
// camera
commands.spawn(Camera3dBundle {
transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
..default()
});
}
// This is the struct that will be passed to your shader
#[derive(AsBindGroup, Clone, TypeUuid, TypePath)]
#[uuid = "4ee9c363-1124-4113-890e-199d81b00281"]
pub struct CustomMaterial {
#[uniform(0)]
color: Color,
#[texture(1)]
#[sampler(2)]
color_texture: Option<Handle<Image>>,
alpha_mode: AlphaMode,
}
/// The Material trait is very configurable, but comes with sensible defaults for all methods.
/// You only need to implement functions for features that need non-default behavior. See the Material api docs for details!
/// When using the GLSL shading language for your shader, the specialize method must be overridden.
impl Material for CustomMaterial {
fn vertex_shader() -> ShaderRef {
"shaders/custom_material.vert".into()
}
fn fragment_shader() -> ShaderRef {
"shaders/custom_material.frag".into()
}
fn alpha_mode(&self) -> AlphaMode {
self.alpha_mode
}
// Bevy assumes by default that vertex shaders use the "vertex" entry point
// and fragment shaders use the "fragment" entry point (for WGSL shaders).
// GLSL uses "main" as the entry point, so we must override the defaults here
fn specialize(
_pipeline: &MaterialPipeline<Self>,
descriptor: &mut RenderPipelineDescriptor,
_layout: &MeshVertexBufferLayout,
_key: MaterialPipelineKey<Self>,
) -> Result<(), SpecializedMeshPipelineError> {
descriptor.vertex.entry_point = "main".into();
descriptor.fragment.as_mut().unwrap().entry_point = "main".into();
Ok(())
}
}