5eca832cee
Adds some methods to assist in building `ShaderStorageBuffer` without using `bytemuck`. We keep the `&[u8]` constructors since this is still modeled as a thin wrapper around the buffer descriptor, but should make it easier to interact with at the cost of an extra allocation in the `ShaderType` path for the buffer writer. Follow up from #14663
107 lines
3.1 KiB
Rust
107 lines
3.1 KiB
Rust
//! This example demonstrates how to use a storage buffer with `AsBindGroup` in a custom material.
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use bevy::{
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prelude::*,
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reflect::TypePath,
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render::render_resource::{AsBindGroup, ShaderRef},
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};
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use bevy_render::storage::ShaderStorageBuffer;
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const SHADER_ASSET_PATH: &str = "shaders/storage_buffer.wgsl";
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fn main() {
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App::new()
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.add_plugins((DefaultPlugins, MaterialPlugin::<CustomMaterial>::default()))
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.add_systems(Startup, setup)
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.add_systems(Update, update)
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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 buffers: ResMut<Assets<ShaderStorageBuffer>>,
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mut materials: ResMut<Assets<CustomMaterial>>,
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) {
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// Example data for the storage buffer
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let color_data: Vec<[f32; 4]> = vec![
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[1.0, 0.0, 0.0, 1.0],
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[0.0, 1.0, 0.0, 1.0],
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[0.0, 0.0, 1.0, 1.0],
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[1.0, 1.0, 0.0, 1.0],
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[0.0, 1.0, 1.0, 1.0],
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];
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let colors = buffers.add(ShaderStorageBuffer::from(color_data));
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// Create the custom material with the storage buffer
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let custom_material = CustomMaterial { colors };
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let material_handle = materials.add(custom_material);
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commands.insert_resource(CustomMaterialHandle(material_handle.clone()));
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// Spawn cubes with the custom material
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for i in -6..=6 {
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for j in -3..=3 {
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commands.spawn(MaterialMeshBundle {
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mesh: meshes.add(Cuboid::from_size(Vec3::splat(0.3))),
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material: material_handle.clone(),
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transform: Transform::from_xyz(i as f32, j as f32, 0.0),
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..default()
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});
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}
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}
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// Camera
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commands.spawn(Camera3dBundle {
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transform: Transform::from_xyz(0.0, 0.0, 10.0).looking_at(Vec3::ZERO, Vec3::Y),
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..default()
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});
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}
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// Update the material color by time
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fn update(
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time: Res<Time>,
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material_handle: Res<CustomMaterialHandle>,
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mut materials: ResMut<Assets<CustomMaterial>>,
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mut buffers: ResMut<Assets<ShaderStorageBuffer>>,
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) {
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let material = materials.get_mut(&material_handle.0).unwrap();
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let buffer = buffers.get_mut(&material.colors).unwrap();
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buffer.set_data(
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(0..5)
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.map(|i| {
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let t = time.elapsed_seconds() * 5.0;
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[
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(t + i as f32).sin() / 2.0 + 0.5,
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(t + i as f32 + 2.0).sin() / 2.0 + 0.5,
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(t + i as f32 + 4.0).sin() / 2.0 + 0.5,
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1.0,
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]
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})
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.collect::<Vec<[f32; 4]>>()
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.as_slice(),
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);
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}
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// Holds a handle to the custom material
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#[derive(Resource)]
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struct CustomMaterialHandle(Handle<CustomMaterial>);
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// This struct defines the data that will be passed to your shader
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#[derive(Asset, TypePath, AsBindGroup, Debug, Clone)]
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struct CustomMaterial {
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#[storage(0, read_only)]
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colors: Handle<ShaderStorageBuffer>,
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}
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impl Material for CustomMaterial {
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fn vertex_shader() -> ShaderRef {
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SHADER_ASSET_PATH.into()
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}
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fn fragment_shader() -> ShaderRef {
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SHADER_ASSET_PATH.into()
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}
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}
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