refactor(srp): clear legacy fullscreen stages before managed planning

docs/used/SRP_UniversalManagedFullscreenPlanningOwnershipPlan_完成归档_2026-04-21.md

@@ -0,0 +1,51 @@
+# SRP Universal Managed Fullscreen Planning Ownership Plan 2026-04-21
+
+## Goal
+
+Make renderer-backed managed pipelines explicitly own fullscreen stage planning by clearing native legacy fullscreen stage state before managed renderer planning runs.
+
+## Why This Stage
+
+The previous stage removed renderer-level fullscreen heuristics, but one legacy seam is still present:
+
+1. native camera-frame policy can prebuild post-process and final-output fullscreen state;
+2. managed URP then reshapes or replaces that state later;
+3. ownership is therefore still mixed during plan construction.
+
+For a Unity-style SRP/URP direction, renderer-backed managed assets should start from a clean fullscreen-stage slate and let managed renderer data/features re-declare the stages they need.
+
+## Scope
+
+Included:
+
+1. clear legacy `PostProcess` and `FinalOutput` stage state at the start of renderer-backed managed planning;
+2. keep this behavior overridable in the renderer-backed asset base;
+3. rebuild `XCEditor` and run old editor smoke.
+
+Not included:
+
+1. removing native final-color policy resolution;
+2. deleting native fullscreen pass implementations;
+3. deleting legacy fullscreen planning for non-managed pipelines;
+4. deferred renderer work.
+
+## Acceptance
+
+This stage is complete when:
+
+1. renderer-backed managed pipelines begin planning with cleared legacy fullscreen stage state;
+2. managed URP still reconstructs the required fullscreen stages through renderer features;
+3. `XCEditor` build passes;
+4. old editor smoke passes and `editor.log` contains a fresh `SceneReady`.
+
+## Validation
+
+Validated on 2026-04-21:
+
+1. built old editor target with `cmake --build . --config Debug --target XCEditor` from `build/`;
+2. launched `editor/bin/Debug/XCEngine.exe` for about 12 seconds;
+3. verified fresh `editor/bin/Debug/editor.log` contains `SceneReady`.
+
+Observed log line:
+
+`[2026-04-21 13:11:41] [INFO] [General] [SceneLoadTrace] SceneReady elapsed_ms=6597 first_frame_ms=757 peak_pending_async=9`

managed/XCEngine.RenderPipelines.Universal/Rendering/Universal/RendererBackedRenderPipelineAsset.cs

@@ -51,6 +51,16 @@ namespace XCEngine.Rendering.Universal
         protected override void ConfigureCameraFramePlan(
             ScriptableRenderPipelinePlanningContext context)
         {
+            if (UsesExplicitFullscreenStagePlanning() &&
+                context != null)
+            {
+                // Renderer-backed SRP owns fullscreen stage planning explicitly.
+                context.ClearFullscreenStage(
+                    CameraFrameStage.PostProcess);
+                context.ClearFullscreenStage(
+                    CameraFrameStage.FinalOutput);
+            }
+
             ScriptableRendererData resolvedRendererData =
                 ResolveRendererData(context);
             if (resolvedRendererData != null)
@@ -220,6 +230,11 @@ namespace XCEngine.Rendering.Universal
             return null;
         }
 
+        protected virtual bool UsesExplicitFullscreenStagePlanning()
+        {
+            return true;
+        }
+
         internal ScriptableRendererData GetDefaultRendererData()
         {
             return ResolveSelectedRendererData();