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https://github.com/bevyengine/bevy
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# 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>
88 lines
2.9 KiB
Rust
88 lines
2.9 KiB
Rust
//! Demonstrates using a custom extension to the `StandardMaterial` to modify the results of the builtin pbr shader.
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use bevy::{
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color::palettes::basic::RED,
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pbr::{ExtendedMaterial, MaterialExtension, OpaqueRendererMethod},
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prelude::*,
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render::render_resource::*,
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};
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/// This example uses a shader source file from the assets subdirectory
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const SHADER_ASSET_PATH: &str = "shaders/extended_material.wgsl";
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fn main() {
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App::new()
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.add_plugins(DefaultPlugins)
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.add_plugins(MaterialPlugin::<
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ExtendedMaterial<StandardMaterial, MyExtension>,
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>::default())
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.add_systems(Startup, setup)
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.add_systems(Update, rotate_things)
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.run();
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}
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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<ExtendedMaterial<StandardMaterial, MyExtension>>>,
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) {
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// sphere
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commands.spawn((
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Mesh3d(meshes.add(Sphere::new(1.0))),
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MeshMaterial3d(materials.add(ExtendedMaterial {
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base: StandardMaterial {
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base_color: RED.into(),
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// can be used in forward or deferred mode.
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opaque_render_method: OpaqueRendererMethod::Auto,
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// in deferred mode, only the PbrInput can be modified (uvs, color and other material properties),
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// in forward mode, the output can also be modified after lighting is applied.
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// see the fragment shader `extended_material.wgsl` for more info.
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// Note: to run in deferred mode, you must also add a `DeferredPrepass` component to the camera and either
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// change the above to `OpaqueRendererMethod::Deferred` or add the `DefaultOpaqueRendererMethod` resource.
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..Default::default()
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},
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extension: MyExtension { quantize_steps: 3 },
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})),
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Transform::from_xyz(0.0, 0.5, 0.0),
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));
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// light
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commands.spawn((
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DirectionalLight::default(),
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Transform::from_xyz(1.0, 1.0, 1.0).looking_at(Vec3::ZERO, Vec3::Y),
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Rotate,
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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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#[derive(Component)]
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struct Rotate;
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fn rotate_things(mut q: Query<&mut Transform, With<Rotate>>, time: Res<Time>) {
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for mut t in &mut q {
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t.rotate_y(time.delta_seconds());
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}
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}
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#[derive(Asset, AsBindGroup, Reflect, Debug, Clone)]
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struct MyExtension {
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// We need to ensure that the bindings of the base material and the extension do not conflict,
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// so we start from binding slot 100, leaving slots 0-99 for the base material.
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#[uniform(100)]
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quantize_steps: u32,
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}
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impl MaterialExtension for MyExtension {
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fn fragment_shader() -> ShaderRef {
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SHADER_ASSET_PATH.into()
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}
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fn deferred_fragment_shader() -> ShaderRef {
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SHADER_ASSET_PATH.into()
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}
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}
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