Revert "fix(render): Phase A8 R3.5 v2 — gate depth-clear on cameraReallyInside too"

This reverts commit 2bfeafd358.

src/AcDream.App/Rendering/GameWindow.cs

@@ -7160,42 +7160,17 @@ public sealed class GameWindow : IDisposable
             _terrainCpuSampleCursor = (_terrainCpuSampleCursor + 1) % _terrainCpuSamples.Length;
             MaybeFlushTerrainDiag();
 
-            // Phase A8 R3.5 — transition-flicker fix. `cameraInsideCell`
+            // Conditional depth clear: when camera is inside a building, clear
-            // stays true for ~3 grace frames after the camera physically
+            // depth (not color) so interior geometry writes fresh Z values on top
-            // exits a cell (see CellVisibility._cellSwitchGraceFrames).
+            // of the terrain color buffer. Exit portals show outdoor terrain color
-            // The grace mechanism prevents sky/lighting flicker at the
+            // because we kept the color buffer. Matching ACME GameScene.cs pattern.
-            // doorway threshold, but the render-frame mechanisms that
+            if (cameraInsideCell)
-            // touch depth (depth-clear AND the stencil pipeline) MUST be
-            // gated on the stricter PointInCell containment so they don't
-            // fire during grace frames when the camera is actually outside.
-            //
-            //   cameraInsideCell    — lenient, grace-aware → sky, lighting
-            //   cameraReallyInside  — PointInCell, no grace → depth-clear,
-            //                          stencil pipeline branch
-            //
-            // R3.5 v1 only gated the stencil branch on `cameraReallyInside`;
-            // depth-clear stayed on `cameraInsideCell`. Result: during grace
-            // frames the depth-clear ran but the outdoor branch ran (because
-            // !cameraReallyInside), so terrain depth was destroyed AND
-            // everything below terrain (cellars, basement geometry) won the
-            // depth test in the outdoor pass → "objects visible through
-            // ground." R3.5 v2 unifies the depth-related gates on
-            // `cameraReallyInside` so terrain depth is preserved during
-            // grace, eliminating the through-ground artifact.
-            bool cameraReallyInside = visibility?.CameraCell is not null
-                && CellVisibility.PointInCell(camPos, visibility.CameraCell);
-
-            // Conditional depth clear: when camera is ACTUALLY inside a cell
-            // volume (not just in the grace window), clear depth (not color)
-            // so interior geometry writes fresh Z values on top of the
-            // terrain color buffer. Matches ACME GameScene.cs pattern.
-            if (cameraReallyInside)
                 _gl!.Clear(ClearBufferMask.DepthBufferBit);
 
             // L-fix1 (2026-04-28): animated-entity id set. Required by both
-            // the cameraReallyInside branch (to route them to LiveDynamic
+            // the cameraInsideCell branch (to route them to LiveDynamic pass)
-            // pass) and the outdoor path (where it preserves visibility
+            // and the outdoor path (where it preserves visibility across
-            // across landblock frustum culling).
+            // landblock frustum culling).
             HashSet<uint>? animatedIds = null;
             if (_animatedEntities.Count > 0)
             {
@@ -7204,6 +7179,23 @@ public sealed class GameWindow : IDisposable
                     animatedIds.Add(k);
             }
 
+            // Phase A8 R3.5 — transition-flicker fix. `cameraInsideCell`
+            // stays true for ~3 grace frames after the camera physically
+            // exits a cell (see CellVisibility._cellSwitchGraceFrames).
+            // The grace mechanism prevents lighting/sky flicker at the
+            // doorway threshold, but if the stencil pipeline runs during
+            // grace frames it marks/punches at the OLD cell's portal
+            // silhouettes — which are now behind/beside the camera — and
+            // the subsequent IndoorPass + stencil-gated outdoor produce
+            // a brief frame of "walls disappear + buildings under ground"
+            // garbage. Gate the stencil branch on the stricter
+            // `PointInCell` containment check so the pipeline only runs
+            // when the camera is ACTUALLY inside its cell volume; sky /
+            // lighting / depth-clear continue to use `cameraInsideCell`
+            // for their smoother grace-aware behavior.
+            bool cameraReallyInside = visibility?.CameraCell is not null
+                && CellVisibility.PointInCell(camPos, visibility.CameraCell);
+
             // The `visibility?.CameraCell is not null` repeat is for the
             // compiler's null-flow analysis: `cameraReallyInside` already
             // implies it, but flow doesn't propagate through a separate