extended material example

.cargo/config.toml

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+[target.x86_64-unknown-linux-gnu]
+linker = "clang"
+rustflags = ["-C", "link-arg=-fuse-ld=/usr/bin/mold"]

.gitignore

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+/target

Cargo.toml

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+[package]
+name = "bevyart"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+bevy = { version = "0.16.0", features = ["shader_format_wesl"] }
+
+# Enable a small amount of optimization in the dev profile.
+[profile.dev]
+opt-level = 1
+
+# Enable a large amount of optimization in the dev profile for dependencies.
+[profile.dev.package."*"]
+opt-level = 3

assets/shaders/material.wgsl

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+#import bevy_pbr::{
+    forward_io::{VertexOutput, FragmentOutput},
+    pbr_fragment::pbr_input_from_standard_material,
+    pbr_functions::{alpha_discard, apply_pbr_lighting, main_pass_post_lighting_processing},
+}
+
+struct MyExtendedMaterial {
+    quantize_steps: u32,
+}
+
+@group(2) @binding(100)
+var<uniform> my_extended_material: MyExtendedMaterial;
+
+@fragment
+fn fragment(
+    in: VertexOutput,
+    @builtin(front_facing) is_front: bool,
+) -> FragmentOutput {
+    var pbr_input = pbr_input_from_standard_material(in, is_front);
+
+    pbr_input.material.base_color = alpha_discard(pbr_input.material, pbr_input.material.base_color);
+
+    var out: FragmentOutput;
+
+    out.color = apply_pbr_lighting(pbr_input);
+
+    out.color = main_pass_post_lighting_processing(pbr_input, out.color);
+
+    return out;
+}

src/main.rs

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+//! Demonstrates using a custom extension to the `StandardMaterial` to modify the results of the builtin pbr shader.
+
+use bevy::{
+    color::palettes::basic::RED,
+    pbr::{ExtendedMaterial, MaterialExtension, OpaqueRendererMethod},
+    prelude::*,
+    render::render_resource::*,
+};
+
+/// This example uses a shader source file from the assets subdirectory
+const SHADER_ASSET_PATH: &str = "shaders/material.wgsl";
+
+fn main() {
+    App::new()
+        .add_plugins(DefaultPlugins)
+        .add_plugins(MaterialPlugin::<
+            ExtendedMaterial<StandardMaterial, MyExtension>,
+        >::default())
+        .add_systems(Startup, setup)
+        .add_systems(Update, rotate_things)
+        .run();
+}
+
+fn setup(
+    mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<ExtendedMaterial<StandardMaterial, MyExtension>>>,
+) {
+    // sphere
+    commands.spawn((
+        Mesh3d(meshes.add(Sphere::new(1.0))),
+        MeshMaterial3d(materials.add(ExtendedMaterial {
+            base: StandardMaterial {
+                base_color: RED.into(),
+                opaque_render_method: OpaqueRendererMethod::Auto,
+                ..Default::default()
+            },
+            extension: MyExtension { quantize_steps: 3 },
+        })),
+        Transform::from_xyz(0.0, 0.5, 0.0),
+    ));
+
+    // light
+    commands.spawn((
+        DirectionalLight::default(),
+        Transform::from_xyz(1.0, 1.0, 1.0).looking_at(Vec3::ZERO, Vec3::Y),
+        Rotate,
+    ));
+
+    // camera
+    commands.spawn((
+        Camera3d::default(),
+        Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
+    ));
+}
+
+#[derive(Component)]
+struct Rotate;
+
+fn rotate_things(mut q: Query<&mut Transform, With<Rotate>>, time: Res<Time>) {
+    for mut t in &mut q {
+        t.rotate_y(time.delta_secs());
+    }
+}
+
+#[derive(Asset, AsBindGroup, Reflect, Debug, Clone)]
+struct MyExtension {
+    #[uniform(100)]
+    quantize_steps: u32,
+}
+
+impl MaterialExtension for MyExtension {
+    fn fragment_shader() -> ShaderRef {
+        SHADER_ASSET_PATH.into()
+    }
+}