1918608b02
# Objective - Changes the default clear color to match the code block color on Bevy's website. ## Solution - Changed the clear color, updated text in examples to ensure adequate contrast. Inconsistent usage of white text color set to use the default color instead, which is already white. - Additionally, updated the `3d_scene` example to make it look a bit better, and use bevy's branding colors. 
255 lines
8.5 KiB
Rust
255 lines
8.5 KiB
Rust
//! Bevy has an optional prepass that is controlled per-material. A prepass is a rendering pass that runs before the main pass.
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//! It will optionally generate various view textures. Currently it supports depth, normal, and motion vector textures.
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//! The textures are not generated for any material using alpha blending.
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use bevy::{
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core_pipeline::prepass::{DepthPrepass, MotionVectorPrepass, NormalPrepass},
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pbr::{NotShadowCaster, PbrPlugin},
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prelude::*,
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reflect::TypePath,
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render::render_resource::{AsBindGroup, ShaderRef, ShaderType},
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};
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fn main() {
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App::new()
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.add_plugins((
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DefaultPlugins.set(PbrPlugin {
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// The prepass is enabled by default on the StandardMaterial,
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// but you can disable it if you need to.
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//
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// prepass_enabled: false,
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..default()
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}),
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MaterialPlugin::<CustomMaterial>::default(),
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MaterialPlugin::<PrepassOutputMaterial> {
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// This material only needs to read the prepass textures,
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// but the meshes using it should not contribute to the prepass render, so we can disable it.
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prepass_enabled: false,
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..default()
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},
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))
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.add_systems(Startup, setup)
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.add_systems(Update, (rotate, toggle_prepass_view))
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// Disabling MSAA for maximum compatibility. Shader prepass with MSAA needs GPU capability MULTISAMPLED_SHADING
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.insert_resource(Msaa::Off)
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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 materials: ResMut<Assets<CustomMaterial>>,
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mut std_materials: ResMut<Assets<StandardMaterial>>,
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mut depth_materials: ResMut<Assets<PrepassOutputMaterial>>,
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asset_server: Res<AssetServer>,
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) {
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// camera
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commands.spawn((
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Camera3dBundle {
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transform: Transform::from_xyz(-2.0, 3., 5.0).looking_at(Vec3::ZERO, Vec3::Y),
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..default()
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},
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// To enable the prepass you need to add the components associated with the ones you need
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// This will write the depth buffer to a texture that you can use in the main pass
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DepthPrepass,
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// This will generate a texture containing world normals (with normal maps applied)
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NormalPrepass,
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// This will generate a texture containing screen space pixel motion vectors
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MotionVectorPrepass,
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));
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// plane
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commands.spawn(PbrBundle {
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mesh: meshes.add(shape::Plane::from_size(5.0).into()),
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material: std_materials.add(Color::rgb(0.3, 0.5, 0.3).into()),
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..default()
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});
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// A quad that shows the outputs of the prepass
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// To make it easy, we just draw a big quad right in front of the camera.
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// For a real application, this isn't ideal.
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commands.spawn((
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MaterialMeshBundle {
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mesh: meshes.add(shape::Quad::new(Vec2::new(20.0, 20.0)).into()),
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material: depth_materials.add(PrepassOutputMaterial {
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settings: ShowPrepassSettings::default(),
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}),
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transform: Transform::from_xyz(-0.75, 1.25, 3.0)
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.looking_at(Vec3::new(2.0, -2.5, -5.0), Vec3::Y),
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..default()
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},
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NotShadowCaster,
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));
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// Opaque cube
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commands.spawn((
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MaterialMeshBundle {
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mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
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material: materials.add(CustomMaterial {
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color: Color::WHITE,
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color_texture: Some(asset_server.load("branding/icon.png")),
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alpha_mode: AlphaMode::Opaque,
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}),
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transform: Transform::from_xyz(-1.0, 0.5, 0.0),
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..default()
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},
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Rotates,
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));
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// Cube with alpha mask
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commands.spawn(PbrBundle {
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mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
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material: std_materials.add(StandardMaterial {
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alpha_mode: AlphaMode::Mask(1.0),
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base_color_texture: Some(asset_server.load("branding/icon.png")),
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..default()
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}),
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transform: Transform::from_xyz(0.0, 0.5, 0.0),
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..default()
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});
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// Cube with alpha blending.
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// Transparent materials are ignored by the prepass
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commands.spawn(MaterialMeshBundle {
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mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
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material: materials.add(CustomMaterial {
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color: Color::WHITE,
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color_texture: Some(asset_server.load("branding/icon.png")),
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alpha_mode: AlphaMode::Blend,
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}),
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transform: Transform::from_xyz(1.0, 0.5, 0.0),
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..default()
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});
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// light
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commands.spawn(PointLightBundle {
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point_light: PointLight {
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intensity: 1500.0,
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shadows_enabled: true,
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..default()
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},
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transform: Transform::from_xyz(4.0, 8.0, 4.0),
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..default()
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});
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let style = TextStyle {
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font_size: 18.0,
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..default()
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};
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commands.spawn(
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TextBundle::from_sections(vec![
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TextSection::new("Prepass Output: transparent\n", style.clone()),
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TextSection::new("\n\n", style.clone()),
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TextSection::new("Controls\n", style.clone()),
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TextSection::new("---------------\n", style.clone()),
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TextSection::new("Space - Change output\n", style),
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])
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.with_style(Style {
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position_type: PositionType::Absolute,
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top: Val::Px(10.0),
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left: Val::Px(10.0),
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..default()
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}),
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);
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}
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// This is the struct that will be passed to your shader
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#[derive(Asset, TypePath, AsBindGroup, Debug, Clone)]
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pub struct CustomMaterial {
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#[uniform(0)]
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color: Color,
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#[texture(1)]
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#[sampler(2)]
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color_texture: Option<Handle<Image>>,
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alpha_mode: AlphaMode,
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}
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/// Not shown in this example, but if you need to specialize your material, the specialize
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/// function will also be used by the prepass
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impl Material for CustomMaterial {
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fn fragment_shader() -> ShaderRef {
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"shaders/custom_material.wgsl".into()
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}
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fn alpha_mode(&self) -> AlphaMode {
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self.alpha_mode
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}
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// You can override the default shaders used in the prepass if your material does
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// anything not supported by the default prepass
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// fn prepass_fragment_shader() -> ShaderRef {
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// "shaders/custom_material.wgsl".into()
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// }
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}
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#[derive(Component)]
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struct Rotates;
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fn rotate(mut q: Query<&mut Transform, With<Rotates>>, time: Res<Time>) {
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for mut t in q.iter_mut() {
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let rot = (time.elapsed_seconds().sin() * 0.5 + 0.5) * std::f32::consts::PI * 2.0;
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t.rotation = Quat::from_rotation_z(rot);
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}
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}
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#[derive(Debug, Clone, Default, ShaderType)]
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struct ShowPrepassSettings {
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show_depth: u32,
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show_normals: u32,
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show_motion_vectors: u32,
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padding_1: u32,
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padding_2: u32,
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}
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// This shader simply loads the prepass texture and outputs it directly
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#[derive(Asset, TypePath, AsBindGroup, Debug, Clone)]
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pub struct PrepassOutputMaterial {
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#[uniform(0)]
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settings: ShowPrepassSettings,
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}
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impl Material for PrepassOutputMaterial {
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fn fragment_shader() -> ShaderRef {
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"shaders/show_prepass.wgsl".into()
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}
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// This needs to be transparent in order to show the scene behind the mesh
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fn alpha_mode(&self) -> AlphaMode {
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AlphaMode::Blend
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}
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}
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/// Every time you press space, it will cycle between transparent, depth and normals view
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fn toggle_prepass_view(
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mut prepass_view: Local<u32>,
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keycode: Res<Input<KeyCode>>,
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material_handle: Query<&Handle<PrepassOutputMaterial>>,
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mut materials: ResMut<Assets<PrepassOutputMaterial>>,
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mut text: Query<&mut Text>,
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) {
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if keycode.just_pressed(KeyCode::Space) {
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*prepass_view = (*prepass_view + 1) % 4;
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let label = match *prepass_view {
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0 => "transparent",
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1 => "depth",
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2 => "normals",
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3 => "motion vectors",
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_ => unreachable!(),
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};
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let mut text = text.single_mut();
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text.sections[0].value = format!("Prepass Output: {label}\n");
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for section in &mut text.sections {
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section.style.color = Color::WHITE;
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}
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let handle = material_handle.single();
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let mat = materials.get_mut(handle).unwrap();
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mat.settings.show_depth = (*prepass_view == 1) as u32;
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mat.settings.show_normals = (*prepass_view == 2) as u32;
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mat.settings.show_motion_vectors = (*prepass_view == 3) as u32;
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}
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}
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