91 lines
2.8 KiB
Rust
91 lines
2.8 KiB
Rust
//! A shader that uses the GLSL shading language.
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use bevy::{
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pbr::{MaterialPipeline, MaterialPipelineKey},
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prelude::*,
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reflect::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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asset_server: Res<AssetServer>,
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) {
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// 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(0.0, 0.5, 0.0),
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material: materials.add(CustomMaterial {
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color: Color::BLUE,
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color_texture: Some(asset_server.load("branding/icon.png")),
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alpha_mode: AlphaMode::Blend,
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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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// This is the struct that will be passed to your shader
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#[derive(AsBindGroup, Clone, TypeUuid)]
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#[uuid = "4ee9c363-1124-4113-890e-199d81b00281"]
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pub struct CustomMaterial {
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#[uniform(0)]
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color: Color,
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#[texture(1)]
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#[sampler(2)]
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color_texture: Option<Handle<Image>>,
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alpha_mode: AlphaMode,
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}
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/// The Material trait is very configurable, but comes with sensible defaults for all methods.
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/// You only need to implement functions for features that need non-default behavior. See the Material api docs for details!
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/// When using the GLSL shading language for your shader, the specialize method must be overridden.
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impl Material for CustomMaterial {
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fn vertex_shader() -> ShaderRef {
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"shaders/custom_material.vert".into()
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}
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fn fragment_shader() -> ShaderRef {
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"shaders/custom_material.frag".into()
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}
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fn alpha_mode(&self) -> AlphaMode {
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self.alpha_mode
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}
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// Bevy assumes by default that vertex shaders use the "vertex" entry point
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// and fragment shaders use the "fragment" entry point (for WGSL shaders).
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// GLSL uses "main" as the entry point, so we must override the defaults here
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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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descriptor.vertex.entry_point = "main".into();
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descriptor.fragment.as_mut().unwrap().entry_point = "main".into();
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Ok(())
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}
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}
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