bevy/examples/3d/fog_volumes.rs
Emerson Coskey 7ab00ca185
Split Camera.hdr out into a new component (#18873)
# Objective

- Simplify `Camera` initialization
- allow effects to require HDR

## Solution

- Split out `Camera.hdr` into a marker `Hdr` component

## Testing

- ran `bloom_3d` example

---

## Showcase

```rs
// before
commands.spawn((
  Camera3d
  Camera {
    hdr: true
    ..Default::default()
  }
))

// after
commands.spawn((Camera3d, Hdr));

// other rendering components can require that the camera enables hdr!
// currently implemented for Bloom, AutoExposure, and Atmosphere.
#[require(Hdr)]
pub struct Bloom;
```
2025-05-26 19:24:45 +00:00

81 lines
2.5 KiB
Rust

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