83 lines
2.6 KiB
Rust
83 lines
2.6 KiB
Rust
//! Demonstrates fog volumes with voxel density textures.
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//!
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//! We render the Stanford bunny as a fog volume. Parts of the bunny become
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//! lighter and darker as the camera rotates. This is physically-accurate
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//! behavior that results from the scattering and absorption of the directional
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//! light.
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use bevy::{
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math::vec3,
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pbr::{FogVolume, VolumetricFog, VolumetricLight},
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prelude::*,
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};
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/// Entry point.
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fn main() {
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App::new()
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.add_plugins(DefaultPlugins.set(WindowPlugin {
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primary_window: Some(Window {
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title: "Bevy Fog Volumes Example".into(),
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..default()
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}),
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..default()
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}))
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.insert_resource(AmbientLight::NONE)
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.add_systems(Startup, setup)
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.add_systems(Update, rotate_camera)
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.run();
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}
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/// Spawns all the objects in the scene.
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fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
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// Spawn a fog volume with a voxelized version of the Stanford bunny.
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commands.spawn((
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Transform::from_xyz(0.0, 0.5, 0.0),
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FogVolume {
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density_texture: Some(asset_server.load("volumes/bunny.ktx2")),
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density_factor: 1.0,
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// Scatter as much of the light as possible, to brighten the bunny
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// up.
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scattering: 1.0,
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..default()
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},
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));
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// Spawn a bright directional light that illuminates the fog well.
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commands.spawn((
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Transform::from_xyz(1.0, 1.0, -0.3).looking_at(vec3(0.0, 0.5, 0.0), Vec3::Y),
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DirectionalLight {
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shadows_enabled: true,
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illuminance: 32000.0,
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..default()
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},
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// Make sure to add this for the light to interact with the fog.
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VolumetricLight,
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));
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// Spawn a camera.
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commands.spawn((
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Camera3d::default(),
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Transform::from_xyz(-0.75, 1.0, 2.0).looking_at(vec3(0.0, 0.0, 0.0), Vec3::Y),
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Camera {
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hdr: true,
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..default()
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},
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VolumetricFog {
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// Make this relatively high in order to increase the fog quality.
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step_count: 64,
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// Disable ambient light.
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ambient_intensity: 0.0,
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..default()
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},
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));
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}
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/// Rotates the camera a bit every frame.
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fn rotate_camera(mut cameras: Query<&mut Transform, With<Camera3d>>) {
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for mut camera_transform in cameras.iter_mut() {
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*camera_transform =
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Transform::from_translation(Quat::from_rotation_y(0.01) * camera_transform.translation)
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.looking_at(vec3(0.0, 0.5, 0.0), Vec3::Y);
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}
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}
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