From 6b837dd2976df486dcace1dc870612479f72692a Mon Sep 17 00:00:00 2001
From: Patrick Walton <pcwalton@mimiga.net>
Date: Thu, 13 Feb 2025 22:43:35 -0800
Subject: [PATCH] Remove prepasses from the render world when they're removed
 from the main world. (#17565)

This makes switching rendering modes in `deferred_rendering` work again.

Closes #16679.
---
 crates/bevy_core_pipeline/src/core_3d/mod.rs | 35 +++++++++++---
 crates/bevy_pbr/src/deferred/mod.rs          | 48 +++++++++++---------
 2 files changed, 56 insertions(+), 27 deletions(-)

diff --git a/crates/bevy_core_pipeline/src/core_3d/mod.rs b/crates/bevy_core_pipeline/src/core_3d/mod.rs
index 7572d80b3944e..d09f6a55250bf 100644
--- a/crates/bevy_core_pipeline/src/core_3d/mod.rs
+++ b/crates/bevy_core_pipeline/src/core_3d/mod.rs
@@ -718,13 +718,35 @@ pub fn extract_camera_prepass_phase(
         }
         live_entities.insert(retained_view_entity);
 
-        commands
+        // Add or remove prepasses as appropriate.
+
+        let mut camera_commands = commands
             .get_entity(entity)
-            .expect("Camera entity wasn't synced.")
-            .insert_if(DepthPrepass, || depth_prepass)
-            .insert_if(NormalPrepass, || normal_prepass)
-            .insert_if(MotionVectorPrepass, || motion_vector_prepass)
-            .insert_if(DeferredPrepass, || deferred_prepass);
+            .expect("Camera entity wasn't synced.");
+
+        if depth_prepass {
+            camera_commands.insert(DepthPrepass);
+        } else {
+            camera_commands.remove::<DepthPrepass>();
+        }
+
+        if normal_prepass {
+            camera_commands.insert(NormalPrepass);
+        } else {
+            camera_commands.remove::<NormalPrepass>();
+        }
+
+        if motion_vector_prepass {
+            camera_commands.insert(MotionVectorPrepass);
+        } else {
+            camera_commands.remove::<MotionVectorPrepass>();
+        }
+
+        if deferred_prepass {
+            camera_commands.insert(DeferredPrepass);
+        } else {
+            camera_commands.remove::<DeferredPrepass>();
+        }
     }
 
     opaque_3d_prepass_phases.retain(|view_entity, _| live_entities.contains(view_entity));
@@ -986,6 +1008,7 @@ pub fn prepare_prepass_textures(
             && !opaque_3d_deferred_phases.contains_key(&view.retained_view_entity)
             && !alpha_mask_3d_deferred_phases.contains_key(&view.retained_view_entity)
         {
+            commands.entity(entity).remove::<ViewPrepassTextures>();
             continue;
         };
 
diff --git a/crates/bevy_pbr/src/deferred/mod.rs b/crates/bevy_pbr/src/deferred/mod.rs
index 5738cdd25dacf..c7d7e04636150 100644
--- a/crates/bevy_pbr/src/deferred/mod.rs
+++ b/crates/bevy_pbr/src/deferred/mod.rs
@@ -432,28 +432,26 @@ pub fn prepare_deferred_lighting_pipelines(
     pipeline_cache: Res<PipelineCache>,
     mut pipelines: ResMut<SpecializedRenderPipelines<DeferredLightingLayout>>,
     deferred_lighting_layout: Res<DeferredLightingLayout>,
-    views: Query<
+    views: Query<(
+        Entity,
+        &ExtractedView,
+        Option<&Tonemapping>,
+        Option<&DebandDither>,
+        Option<&ShadowFilteringMethod>,
         (
-            Entity,
-            &ExtractedView,
-            Option<&Tonemapping>,
-            Option<&DebandDither>,
-            Option<&ShadowFilteringMethod>,
-            (
-                Has<ScreenSpaceAmbientOcclusion>,
-                Has<ScreenSpaceReflectionsUniform>,
-                Has<DistanceFog>,
-            ),
-            (
-                Has<NormalPrepass>,
-                Has<DepthPrepass>,
-                Has<MotionVectorPrepass>,
-            ),
-            Has<RenderViewLightProbes<EnvironmentMapLight>>,
-            Has<RenderViewLightProbes<IrradianceVolume>>,
+            Has<ScreenSpaceAmbientOcclusion>,
+            Has<ScreenSpaceReflectionsUniform>,
+            Has<DistanceFog>,
+        ),
+        (
+            Has<NormalPrepass>,
+            Has<DepthPrepass>,
+            Has<MotionVectorPrepass>,
+            Has<DeferredPrepass>,
         ),
-        With<DeferredPrepass>,
-    >,
+        Has<RenderViewLightProbes<EnvironmentMapLight>>,
+        Has<RenderViewLightProbes<IrradianceVolume>>,
+    )>,
 ) {
     for (
         entity,
@@ -462,11 +460,19 @@ pub fn prepare_deferred_lighting_pipelines(
         dither,
         shadow_filter_method,
         (ssao, ssr, distance_fog),
-        (normal_prepass, depth_prepass, motion_vector_prepass),
+        (normal_prepass, depth_prepass, motion_vector_prepass, deferred_prepass),
         has_environment_maps,
         has_irradiance_volumes,
     ) in &views
     {
+        // If there is no deferred prepass, remove the old pipeline if there was
+        // one. This handles the case in which a view using deferred stops using
+        // it.
+        if !deferred_prepass {
+            commands.entity(entity).remove::<DeferredLightingPipeline>();
+            continue;
+        }
+
         let mut view_key = MeshPipelineKey::from_hdr(view.hdr);
 
         if normal_prepass {