Trait bevy_pbr::Material

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pub trait Material: Asset + AsBindGroup + Clone + Sized {
    // Provided methods
    fn vertex_shader() -> ShaderRef { ... }
    fn fragment_shader() -> ShaderRef { ... }
    fn alpha_mode(&self) -> AlphaMode { ... }
    fn opaque_render_method(&self) -> OpaqueRendererMethod { ... }
    fn depth_bias(&self) -> f32 { ... }
    fn reads_view_transmission_texture(&self) -> bool { ... }
    fn prepass_vertex_shader() -> ShaderRef { ... }
    fn prepass_fragment_shader() -> ShaderRef { ... }
    fn deferred_vertex_shader() -> ShaderRef { ... }
    fn deferred_fragment_shader() -> ShaderRef { ... }
    fn specialize(
        pipeline: &MaterialPipeline<Self>,
        descriptor: &mut RenderPipelineDescriptor,
        layout: &MeshVertexBufferLayout,
        key: MaterialPipelineKey<Self>
    ) -> Result<(), SpecializedMeshPipelineError> { ... }
}
Expand description

Materials are used alongside MaterialPlugin and MaterialMeshBundle to spawn entities that are rendered with a specific Material type. They serve as an easy to use high level way to render Mesh entities with custom shader logic.

Materials must implement AsBindGroup to define how data will be transferred to the GPU and bound in shaders. AsBindGroup can be derived, which makes generating bindings straightforward. See the AsBindGroup docs for details.

Example

Here is a simple Material implementation. The AsBindGroup derive has many features. To see what else is available, check out the AsBindGroup documentation.


#[derive(AsBindGroup, Debug, Clone, Asset, TypePath)]
pub struct CustomMaterial {
    // Uniform bindings must implement `ShaderType`, which will be used to convert the value to
    // its shader-compatible equivalent. Most core math types already implement `ShaderType`.
    #[uniform(0)]
    color: Color,
    // Images can be bound as textures in shaders. If the Image's sampler is also needed, just
    // add the sampler attribute with a different binding index.
    #[texture(1)]
    #[sampler(2)]
    color_texture: Handle<Image>,
}

// All functions on `Material` have default impls. You only need to implement the
// functions that are relevant for your material.
impl Material for CustomMaterial {
    fn fragment_shader() -> ShaderRef {
        "shaders/custom_material.wgsl".into()
    }
}

// Spawn an entity using `CustomMaterial`.
fn setup(mut commands: Commands, mut materials: ResMut<Assets<CustomMaterial>>, asset_server: Res<AssetServer>) {
    commands.spawn(MaterialMeshBundle {
        material: materials.add(CustomMaterial {
            color: Color::RED,
            color_texture: asset_server.load("some_image.png"),
        }),
        ..Default::default()
    });
}

In WGSL shaders, the material’s binding would look like this:

@group(2) @binding(0) var<uniform> color: vec4<f32>;
@group(2) @binding(1) var color_texture: texture_2d<f32>;
@group(2) @binding(2) var color_sampler: sampler;

Provided Methods§

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fn vertex_shader() -> ShaderRef

Returns this material’s vertex shader. If ShaderRef::Default is returned, the default mesh vertex shader will be used.

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fn fragment_shader() -> ShaderRef

Returns this material’s fragment shader. If ShaderRef::Default is returned, the default mesh fragment shader will be used.

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fn alpha_mode(&self) -> AlphaMode

Returns this material’s AlphaMode. Defaults to AlphaMode::Opaque.

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fn opaque_render_method(&self) -> OpaqueRendererMethod

Returns if this material should be rendered by the deferred or forward renderer. for AlphaMode::Opaque or AlphaMode::Mask materials. If OpaqueRendererMethod::Auto, it will default to what is selected in the DefaultOpaqueRendererMethod resource.

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fn depth_bias(&self) -> f32

Add a bias to the view depth of the mesh which can be used to force a specific render order. for meshes with similar depth, to avoid z-fighting. The bias is in depth-texture units so large values may be needed to overcome small depth differences.

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fn reads_view_transmission_texture(&self) -> bool

Returns whether the material would like to read from ViewTransmissionTexture.

This allows taking color output from the Opaque3d pass as an input, (for screen-space transmission) but requires rendering to take place in a separate Transmissive3d pass.

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fn prepass_vertex_shader() -> ShaderRef

Returns this material’s prepass vertex shader. If ShaderRef::Default is returned, the default prepass vertex shader will be used.

This is used for the various prepasses as well as for generating the depth maps required for shadow mapping.

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fn prepass_fragment_shader() -> ShaderRef

Returns this material’s prepass fragment shader. If ShaderRef::Default is returned, the default prepass fragment shader will be used.

This is used for the various prepasses as well as for generating the depth maps required for shadow mapping.

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fn deferred_vertex_shader() -> ShaderRef

Returns this material’s deferred vertex shader. If ShaderRef::Default is returned, the default deferred vertex shader will be used.

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fn deferred_fragment_shader() -> ShaderRef

Returns this material’s deferred fragment shader. If ShaderRef::Default is returned, the default deferred fragment shader will be used.

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fn specialize( pipeline: &MaterialPipeline<Self>, descriptor: &mut RenderPipelineDescriptor, layout: &MeshVertexBufferLayout, key: MaterialPipelineKey<Self> ) -> Result<(), SpecializedMeshPipelineError>

Customizes the default RenderPipelineDescriptor for a specific entity using the entity’s MaterialPipelineKey and MeshVertexBufferLayout as input.

Object Safety§

This trait is not object safe.

Implementors§