fix(light despawn / pcss example): add extracted lights and shadow related components to SyncComponent for lights (bevyengine#23790)

# Objective

- Fixes bevyengine#23769 !

## Solution

I `git bisect`’d the issue to bbcc1e6
which has to do with `SyncComponent`s. The problem was that not all the
relevant components were being despawned when toggling an entity between
different Light components within the example. Expanding
`SyncComponents` for each light ensures that the lights clean up
properly between toggling.

I also had to review bevyengine#23713 and I connected the dots that de-spawning
the light should also despawn the light view entity. Duh!

## Testing

- `cargo run --example pcss --features=“experimental_pbr_pcss”`:
toggling works!

Author: kfc35

crates/bevy_pbr/src/lib.rs

@@ -30,7 +30,10 @@ pub mod contact_shadows;
 #[cfg(feature = "bevy_gltf")]
 mod gltf;
 use bevy_light::cluster::GlobalClusterSettings;
-use bevy_render::sync_component::SyncComponent;
+use bevy_render::{
+    sync_component::SyncComponent,
+    view::{RenderExtractedShadowMapVisibleEntities, RenderShadowMapVisibleEntities},
+};
 pub use contact_shadows::{
     ContactShadows, ContactShadowsBuffer, ContactShadowsPlugin, ContactShadowsUniform,
     ViewContactShadowsUniformOffset,
@@ -418,7 +421,9 @@ impl Plugin for PbrPlugin {
         render_app
             .world_mut()
             .add_observer(remove_light_view_entities);
-        render_app.world_mut().add_observer(extracted_light_removed);
+        render_app
+            .world_mut()
+            .add_observer(remove_point_and_spot_light_view_entities);
 
         render_app.add_systems(
             Core3d,
@@ -477,16 +482,34 @@ pub fn stbn_placeholder() -> Image {
 }
 
 impl SyncComponent<PbrPlugin> for DirectionalLight {
-    type Target = Self;
+    type Target = (
+        Self,
+        ExtractedDirectionalLight,
+        RenderExtractedShadowMapVisibleEntities,
+        RenderShadowMapVisibleEntities,
+        DirectionalLightViewEntities,
+    );
 }
 impl SyncComponent<PbrPlugin> for PointLight {
-    type Target = Self;
+    type Target = (
+        Self,
+        ExtractedPointLight,
+        RenderExtractedShadowMapVisibleEntities,
+        RenderShadowMapVisibleEntities,
+        PointAndSpotLightViewEntities,
+    );
 }
 impl SyncComponent<PbrPlugin> for SpotLight {
-    type Target = Self;
+    type Target = (
+        Self,
+        ExtractedPointLight,
+        RenderExtractedShadowMapVisibleEntities,
+        RenderShadowMapVisibleEntities,
+        PointAndSpotLightViewEntities,
+    );
 }
 impl SyncComponent<PbrPlugin> for RectLight {
-    type Target = Self;
+    type Target = (Self, ExtractedRectLight);
 }
 impl SyncComponent<PbrPlugin> for AmbientLight {
     type Target = Self;

crates/bevy_pbr/src/render/light.rs

@@ -45,8 +45,7 @@ use bevy_render::mesh::allocator::MeshSlabs;
 use bevy_render::occlusion_culling::{
     OcclusionCulling, OcclusionCullingSubview, OcclusionCullingSubviewEntities,
 };
-use bevy_render::sync_world::{MainEntity, RenderEntity};
-use bevy_render::sync_world::{MainEntityHashMap, MainEntityHashSet};
+use bevy_render::sync_world::{MainEntity, MainEntityHashMap, RenderEntity};
 use bevy_render::view::{
     RenderExtractedShadowMapVisibleEntities, RenderShadowMapVisibleEntities, RenderVisibleEntities,
     VisibilityExtractionSystemParam,
@@ -421,17 +420,6 @@ pub fn extract_lights(
         &mut RenderExtractedShadowMapVisibleEntities,
         &mut RenderShadowMapVisibleEntities,
     )>,
-    (
-        mut removed_point_lights,
-        mut removed_spot_lights,
-        mut removed_directional_lights,
-        mut removed_rect_lights,
-    ): (
-        Extract<RemovedComponents<PointLight>>,
-        Extract<RemovedComponents<SpotLight>>,
-        Extract<RemovedComponents<DirectionalLight>>,
-        Extract<RemovedComponents<RectLight>>,
-    ),
 ) {
     let mapper = &visibility_extraction_system_param.mapper;
 
@@ -453,14 +441,6 @@ pub fn extract_lights(
     // https://catlikecoding.com/unity/tutorials/custom-srp/point-and-spot-shadows/
     let point_light_texel_size = 2.0 / point_light_shadow_map.size as f32;
 
-    // Keep track of all entities of a type that we updated this frame, so that
-    // we don't incorrectly remove the components later even if they show up in
-    // `RemovedComponents`.
-    let mut seen_point_light_main_entities = MainEntityHashSet::default();
-    let mut seen_spot_light_main_entities = MainEntityHashSet::default();
-    let mut seen_directional_light_main_entities = MainEntityHashSet::default();
-    let mut seen_rect_light_main_entities = MainEntityHashSet::default();
-
     for (
         main_entity,
         render_entity,
@@ -472,8 +452,6 @@ pub fn extract_lights(
         volumetric_light,
     ) in point_lights.iter()
     {
-        seen_point_light_main_entities.insert(main_entity.into());
-
         if !view_visibility.get() {
             if let Ok(mut entity_commands) = commands.get_entity(render_entity) {
                 entity_commands.remove::<ExtractedPointLight>();
@@ -586,8 +564,6 @@ pub fn extract_lights(
         volumetric_light,
     ) in spot_lights.iter()
     {
-        seen_spot_light_main_entities.insert(main_entity.into());
-
         if !view_visibility.get() {
             if let Ok(mut entity_commands) = commands.get_entity(render_entity) {
                 entity_commands.remove::<ExtractedPointLight>();
@@ -706,8 +682,6 @@ pub fn extract_lights(
         sun_disk,
     ) in &directional_lights
     {
-        seen_directional_light_main_entities.insert(main_entity.into());
-
         if !view_visibility.get() {
             commands
                 .get_entity(entity)
@@ -850,8 +824,6 @@ pub fn extract_lights(
     }
 
     for (main_entity, render_entity, rect_light, transform, view_visibility) in &rect_lights {
-        seen_rect_light_main_entities.insert(main_entity.into());
-
         if !view_visibility.get() {
             if let Ok(mut entity_commands) = commands.get_entity(render_entity) {
                 entity_commands.remove::<ExtractedRectLight>();
@@ -879,64 +851,6 @@ pub fn extract_lights(
             ));
     }
 
-    // Remove extracted light components from entities that have had their
-    // light components removed.
-    remove_components::<PointLight, ExtractedPointLight>(
-        &mut commands,
-        mapper,
-        &mut removed_point_lights,
-        &seen_point_light_main_entities,
-    );
-    remove_components::<SpotLight, ExtractedPointLight>(
-        &mut commands,
-        mapper,
-        &mut removed_spot_lights,
-        &seen_spot_light_main_entities,
-    );
-    remove_components::<DirectionalLight, ExtractedDirectionalLight>(
-        &mut commands,
-        mapper,
-        &mut removed_directional_lights,
-        &seen_directional_light_main_entities,
-    );
-    remove_components::<RectLight, ExtractedRectLight>(
-        &mut commands,
-        mapper,
-        &mut removed_rect_lights,
-        &seen_rect_light_main_entities,
-    );
-
-    // A helper function that removes a render-world component `RWC` when a
-    // main-world component `MC` is removed.
-    //
-    // `seen_entities` is the list of all entities with that component that were
-    // updated this frame. It's needed because presence in the
-    // `RemovedComponents` table for the main-world component isn't enough to
-    // determine whether the render-world component can be removed, as the
-    // main-world component might have been removed and then re-added in the
-    // same frame.
-    fn remove_components<MC, RWC>(
-        commands: &mut Commands,
-        mapper: &Query<&RenderEntity>,
-        removed_components: &mut RemovedComponents<MC>,
-        seen_entities: &MainEntityHashSet,
-    ) where
-        MC: Component,
-        RWC: Component,
-    {
-        // As usual, only remove components if we didn't process them in the
-        // outer extraction function, because of the possibility that the
-        // component might have been removed and re-added in the same frame.
-        for main_entity in removed_components.read() {
-            if !seen_entities.contains(&MainEntity::from(main_entity))
-                && let Ok(render_entity) = mapper.get(main_entity)
-                && let Ok(mut entity_commands) = commands.get_entity(**render_entity)
-            {
-                entity_commands.remove::<RWC>();
-            }
-        }
-    }
-
     /// Clears out any shadow maps that may be present for a light with shadow
     /// mapping turned off.
     fn clear_shadow_maps(commands: &mut Commands, render_entity: Entity) {
@@ -965,17 +879,6 @@ pub(crate) fn add_light_view_entities(
     }
 }
 
-/// Removes [`DirectionalLightViewEntities`] when light is removed. See
-/// [`add_light_view_entities`].
-pub(crate) fn extracted_light_removed(
-    remove: On<Remove, ExtractedDirectionalLight>,
-    mut commands: Commands,
-) {
-    if let Ok(mut v) = commands.get_entity(remove.entity) {
-        v.try_remove::<DirectionalLightViewEntities>();
-    }
-}
-
 pub(crate) fn remove_light_view_entities(
     remove: On<Remove, DirectionalLightViewEntities>,
     query: Query<&DirectionalLightViewEntities>,
@@ -992,6 +895,20 @@ pub(crate) fn remove_light_view_entities(
     }
 }
 
+pub(crate) fn remove_point_and_spot_light_view_entities(
+    remove: On<Remove, PointAndSpotLightViewEntities>,
+    query: Query<&PointAndSpotLightViewEntities>,
+    mut commands: Commands,
+) {
+    if let Ok(entities) = query.get(remove.entity) {
+        for e in entities.0.iter().copied() {
+            if let Ok(mut v) = commands.get_entity(e) {
+                v.despawn();
+            }
+        }
+    }
+}
+
 /// A component that stores the shadow maps associated with a point or spot
 /// light.
 ///