# Objective Fixes #15560 Fixes (most of) #15570 Currently a lot of examples (and presumably some user code) depend on toggling certain render features by adding/removing a single component to an entity, e.g. `SpotLight` to toggle a light. Because of the retained render world this no longer works: Extract will add any new components, but when it is removed the entity persists unchanged in the render world. ## Solution Add `SyncComponentPlugin<C: Component>` that registers `SyncToRenderWorld` as a required component for `C`, and adds a component hook that will clear all components from the render world entity when `C` is removed. We add this plugin to `ExtractComponentPlugin` which fixes most instances of the problem. For custom extraction logic we can manually add `SyncComponentPlugin` for that component. We also rename `WorldSyncPlugin` to `SyncWorldPlugin` so we start a naming convention like all the `Extract` plugins. In this PR I also fixed a bunch of breakage related to the retained render world, stemming from old code that assumed that `Entity` would be the same in both worlds. I found that using the `RenderEntity` wrapper instead of `Entity` in data structures when referring to render world entities makes intent much clearer, so I propose we make this an official pattern. ## Testing Run examples like ``` cargo run --features pbr_multi_layer_material_textures --example clearcoat cargo run --example volumetric_fog ``` and see that they work, and that toggles work correctly. But really we should test every single example, as we might not even have caught all the breakage yet. --- ## Migration Guide The retained render world notes should be updated to explain this edge case and `SyncComponentPlugin` --------- Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com> Co-authored-by: Trashtalk217 <trashtalk217@gmail.com>
		
			
				
	
	
		
			86 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			86 lines
		
	
	
		
			2.7 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
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        .spawn(SpatialBundle {
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            visibility: Visibility::Visible,
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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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        .insert(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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    // 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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