docs/bevy/examples/3d/decal.rs 4.5 K · 134 lines · raw · history

1 //! Decal rendering.
2 //! Note: On Wasm, this example only runs on WebGPU
3
4 use bevy::{
5 camera_controller::free_camera::{FreeCamera, FreeCameraPlugin},
6 core_pipeline::prepass::DepthPrepass,
7 pbr::decal::{ForwardDecal, ForwardDecalMaterial, ForwardDecalMaterialExt},
8 prelude::*,
9 };
10 use chacha20::ChaCha8Rng;
11 use rand::{RngExt, SeedableRng};
12
13 fn main() {
14 App::new()
15 .add_plugins((DefaultPlugins, FreeCameraPlugin))
16 .add_systems(Startup, setup)
17 .run();
18 }
19
20 fn setup(
21 mut commands: Commands,
22 mut meshes: ResMut<Assets<Mesh>>,
23 mut standard_materials: ResMut<Assets<StandardMaterial>>,
24 mut decal_standard_materials: ResMut<Assets<ForwardDecalMaterial<StandardMaterial>>>,
25 asset_server: Res<AssetServer>,
26 ) {
27 // Spawn the forward decal
28 commands.spawn((
29 Name::new("Decal Blue"),
30 ForwardDecal,
31 MeshMaterial3d(decal_standard_materials.add(ForwardDecalMaterial {
32 base: StandardMaterial {
33 base_color_texture: Some(asset_server.load("textures/uv_checker_bw.png")),
34 base_color: Color::srgb(0.3, 0.5, 0.8),
35 alpha_mode: AlphaMode::Opaque,
36 depth_bias: 0.0,
37 ..default()
38 },
39 extension: ForwardDecalMaterialExt {
40 depth_fade_factor: 1.0,
41 },
42 })),
43 Transform::from_scale(Vec3::splat(4.0)).with_translation(Vec3::new(-1.0, 0.0, -1.0)),
44 ));
45
46 commands.spawn((
47 Name::new("Decal Green"),
48 ForwardDecal,
49 MeshMaterial3d(decal_standard_materials.add(ForwardDecalMaterial {
50 base: StandardMaterial {
51 base_color_texture: Some(asset_server.load("textures/uv_checker_bw.png")),
52 base_color: Color::srgba(0.0, 1.0, 0.0, 0.5),
53 alpha_mode: AlphaMode::Blend,
54 depth_bias: 2.0,
55 ..default()
56 },
57 extension: ForwardDecalMaterialExt {
58 depth_fade_factor: 1.0,
59 },
60 })),
61 Transform::from_scale(Vec3::splat(4.0)).with_translation(Vec3::new(1.0, 0.0, -1.0)),
62 ));
63
64 commands.spawn((
65 Name::new("Decal Red"),
66 ForwardDecal,
67 MeshMaterial3d(decal_standard_materials.add(ForwardDecalMaterial {
68 base: StandardMaterial {
69 base_color_texture: Some(asset_server.load("textures/uv_checker_bw.png")),
70 base_color: Color::srgba(1.0, 0.0, 0.0, 0.5),
71 alpha_mode: AlphaMode::Add,
72 depth_bias: 4.0,
73 ..default()
74 },
75 extension: ForwardDecalMaterialExt {
76 depth_fade_factor: 1.0,
77 },
78 })),
79 Transform::from_scale(Vec3::splat(4.0)).with_translation(Vec3::new(0.0, 0.0, 1.0)),
80 ));
81
82 commands.spawn((
83 Name::new("Camera"),
84 Camera3d::default(),
85 FreeCamera::default(),
86 // Must enable the depth prepass to render forward decals
87 DepthPrepass,
88 Transform::from_xyz(2.0, 9.5, 2.5).looking_at(Vec3::ZERO, Vec3::Y),
89 ));
90
91 let white_material = standard_materials.add(Color::WHITE);
92
93 commands.spawn((
94 Name::new("Floor"),
95 Mesh3d(meshes.add(Rectangle::from_length(10.0))),
96 MeshMaterial3d(white_material.clone()),
97 Transform::from_rotation(Quat::from_rotation_x(-std::f32::consts::FRAC_PI_2)),
98 ));
99
100 // Spawn a few cube with random rotations to showcase how the decals behave with non-flat geometry
101 let num_obs = 10;
102 let mut rng = ChaCha8Rng::seed_from_u64(19878367467713);
103 for i in 0..num_obs {
104 for j in 0..num_obs {
105 let rotation_axis: [f32; 3] = rng.random();
106 let rotation_vec: Vec3 = rotation_axis.into();
107 let rotation: u32 = rng.random_range(0..360);
108 let transform = Transform::from_xyz(
109 (-num_obs + 1) as f32 / 2.0 + i as f32,
110 -0.2,
111 (-num_obs + 1) as f32 / 2.0 + j as f32,
112 )
113 .with_rotation(Quat::from_axis_angle(
114 rotation_vec.normalize_or_zero(),
115 (rotation as f32).to_radians(),
116 ));
117
118 commands.spawn((
119 Mesh3d(meshes.add(Cuboid::from_length(0.6))),
120 MeshMaterial3d(white_material.clone()),
121 transform,
122 ));
123 }
124 }
125
126 commands.spawn((
127 Name::new("Light"),
128 PointLight {
129 shadow_maps_enabled: true,
130 ..default()
131 },
132 Transform::from_xyz(4.0, 8.0, 4.0),
133 ));
134 }