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https://github.com/bevyengine/bevy
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54006b107b
# Objective A big step in the migration to required components: meshes and materials! ## Solution As per the [selected proposal](https://hackmd.io/@bevy/required_components/%2Fj9-PnF-2QKK0on1KQ29UWQ): - Deprecate `MaterialMesh2dBundle`, `MaterialMeshBundle`, and `PbrBundle`. - Add `Mesh2d` and `Mesh3d` components, which wrap a `Handle<Mesh>`. - Add `MeshMaterial2d<M: Material2d>` and `MeshMaterial3d<M: Material>`, which wrap a `Handle<M>`. - Meshes *without* a mesh material should be rendered with a default material. The existence of a material is determined by `HasMaterial2d`/`HasMaterial3d`, which is required by `MeshMaterial2d`/`MeshMaterial3d`. This gets around problems with the generics. Previously: ```rust commands.spawn(MaterialMesh2dBundle { mesh: meshes.add(Circle::new(100.0)).into(), material: materials.add(Color::srgb(7.5, 0.0, 7.5)), transform: Transform::from_translation(Vec3::new(-200., 0., 0.)), ..default() }); ``` Now: ```rust commands.spawn(( Mesh2d(meshes.add(Circle::new(100.0))), MeshMaterial2d(materials.add(Color::srgb(7.5, 0.0, 7.5))), Transform::from_translation(Vec3::new(-200., 0., 0.)), )); ``` If the mesh material is missing, previously nothing was rendered. Now, it renders a white default `ColorMaterial` in 2D and a `StandardMaterial` in 3D (this can be overridden). Below, only every other entity has a material:   Why white? This is still open for discussion, but I think white makes sense for a *default* material, while *invalid* asset handles pointing to nothing should have something like a pink material to indicate that something is broken (I don't handle that in this PR yet). This is kind of a mix of Godot and Unity: Godot just renders a white material for non-existent materials, while Unity renders nothing when no materials exist, but renders pink for invalid materials. I can also change the default material to pink if that is preferable though. ## Testing I ran some 2D and 3D examples to test if anything changed visually. I have not tested all examples or features yet however. If anyone wants to test more extensively, it would be appreciated! ## Implementation Notes - The relationship between `bevy_render` and `bevy_pbr` is weird here. `bevy_render` needs `Mesh3d` for its own systems, but `bevy_pbr` has all of the material logic, and `bevy_render` doesn't depend on it. I feel like the two crates should be refactored in some way, but I think that's out of scope for this PR. - I didn't migrate meshlets to required components yet. That can probably be done in a follow-up, as this is already a huge PR. - It is becoming increasingly clear to me that we really, *really* want to disallow raw asset handles as components. They caused me a *ton* of headache here already, and it took me a long time to find every place that queried for them or inserted them directly on entities, since there were no compiler errors for it. If we don't remove the `Component` derive, I expect raw asset handles to be a *huge* footgun for users as we transition to wrapper components, especially as handles as components have been the norm so far. I personally consider this to be a blocker for 0.15: we need to migrate to wrapper components for asset handles everywhere, and remove the `Component` derive. Also see https://github.com/bevyengine/bevy/issues/14124. --- ## Migration Guide Asset handles for meshes and mesh materials must now be wrapped in the `Mesh2d` and `MeshMaterial2d` or `Mesh3d` and `MeshMaterial3d` components for 2D and 3D respectively. Raw handles as components no longer render meshes. Additionally, `MaterialMesh2dBundle`, `MaterialMeshBundle`, and `PbrBundle` have been deprecated. Instead, use the mesh and material components directly. Previously: ```rust commands.spawn(MaterialMesh2dBundle { mesh: meshes.add(Circle::new(100.0)).into(), material: materials.add(Color::srgb(7.5, 0.0, 7.5)), transform: Transform::from_translation(Vec3::new(-200., 0., 0.)), ..default() }); ``` Now: ```rust commands.spawn(( Mesh2d(meshes.add(Circle::new(100.0))), MeshMaterial2d(materials.add(Color::srgb(7.5, 0.0, 7.5))), Transform::from_translation(Vec3::new(-200., 0., 0.)), )); ``` If the mesh material is missing, a white default material is now used. Previously, nothing was rendered if the material was missing. The `WithMesh2d` and `WithMesh3d` query filter type aliases have also been removed. Simply use `With<Mesh2d>` or `With<Mesh3d>`. --------- Co-authored-by: Tim Blackbird <justthecooldude@gmail.com> Co-authored-by: Carter Anderson <mcanders1@gmail.com>
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::{
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render_resource::{AsBindGroup, ShaderRef},
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storage::ShaderStorageBuffer,
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},
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};
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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((
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Mesh3d(meshes.add(Cuboid::from_size(Vec3::splat(0.3)))),
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MeshMaterial3d(material_handle.clone()),
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Transform::from_xyz(i as f32, j as f32, 0.0),
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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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ops::sin(t + i as f32) / 2.0 + 0.5,
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ops::sin(t + i as f32 + 2.0) / 2.0 + 0.5,
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ops::sin(t + i as f32 + 4.0) / 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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