revert(render): BR-2 depth discipline - the gate proved #108 is MEMBERSHIP, not depth

Visual gate (2026-06-11) on the seal+punch build, then on the punch-reverted
build, isolated the truth:
- With the punch wired: #108 (cellar grass-sweep) gone BUT the player/NPCs
  go transparent by exactly their overlap with any doorway viewed from
  outside (the far-Z punch erases the depth of dynamic objects standing in
  the aperture, so the interior paints over them).
- With ONLY the punch reverted (seal+full-clear kept): characters render
  correctly AND #108 is BACK.

The punch is wired for OUTDOOR roots + the look-in path ONLY; it never runs
on a clean interior (cellar) frame. For it to have suppressed #108, the
cellar-transition frames must render through the OUTDOOR root -> the player
is being classified OUTDOOR mid-cellar (the known #112/#106 cellar
membership ping-pong). So:
- #108 is a MEMBERSHIP bug (render is downstream of membership); the punch
  was MASKING it, harmfully. Re-attributed to the membership track.
- The interior-root SEAL addresses a case that is NOT #108 (confirmed: #108
  isn't an interior-root frame), so it has no verified visible effect yet.

Per no-workarounds + verify-before-layering: reverted ALL of BR-2's depth
machinery (seal, punch, the per-slice->full-clear swap) to the pre-BR-2
baseline (restored from 6cba950). The phantom-site probe (6cba950) is kept.
PortalDepthMaskRenderer.cs is KEPT as a RESERVED, unwired primitive (it is
verified-correct; the depth discipline will be rebuilt during BR-3 with
dynamics-after-interior ordering, where it can be verified against the
shell-chop deletion).

What survives from this session's execution: BR-1 (already-equivalent,
695eca2) stands. #108 moves to membership. BR-2 to be re-approached under
BR-3 with correct ordering. No net production behavior change vs 6cba950.

Suites: build green, App 226 green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/AcDream.App/Rendering/GameWindow.cs

@@ -171,7 +171,6 @@ public sealed class GameWindow : IDisposable
     // each frame on an indoor root (null on the outdoor root).
     private AcDream.App.Rendering.InteriorRenderer? _interiorRenderer;
     private AcDream.App.Rendering.RetailPViewRenderer? _retailPViewRenderer;
-    private AcDream.App.Rendering.PortalDepthMaskRenderer? _portalDepthMask;
     private AcDream.App.Rendering.InteriorEntityPartition.Result? _interiorPartition;
 
     // Phase U.3: the shared per-frame clip data (binding=2 mesh SSBO + terrain
@@ -1846,10 +1845,6 @@ public sealed class GameWindow : IDisposable
             _clipFrame ??= ClipFrame.NoClip();
             _retailPViewRenderer = new AcDream.App.Rendering.RetailPViewRenderer(
                 _gl, _clipFrame, _envCellRenderer!, _wbDrawDispatcher!);
-
-            // BR-2: invisible portal depth writes (seal/punch) — retail
-            // DrawPortalPolyInternal (Ghidra 0x0059bc90).
-            _portalDepthMask = new AcDream.App.Rendering.PortalDepthMaskRenderer(_gl);
         }
 
         // Phase G.1 sky renderer — its own shader (sky.vert / sky.frag)
@@ -7637,31 +7632,24 @@ public sealed class GameWindow : IDisposable
                             renderSky,
                             kf,
                             environOverrideActive),
-                    // BR-2: retail's depth discipline between the outside stage and the
+                    // The depth clear is a doorway "look-in" trick: clear depth inside a door/window
-                    // interior stage (PView::DrawCells, Ghidra 0x005a4840): one FULL depth
+                    // region so the cell seen THROUGH it draws over the terrain drawn through that
-                    // clear (no scissor — the old per-slice AABB clear was the wrong shape),
+                    // region (the indoor root looking out). For the OUTDOOR-node root the only
-                    // then DrawExitPortalMasks re-stamps every outside-leading portal's TRUE
+                    // OutsideView slice is the FULL-SCREEN base terrain, so clearing its depth wipes the
-                    // depth so terrain seen through a doorway keeps its pixels (#108).
+                    // entire depth buffer AFTER terrain/exteriors/player drew — the flooded building
-                    // For the OUTDOOR-node root the only OutsideView slice is the FULL-SCREEN
+                    // interiors (cellars) would then paint over everything (cellar in front of the
-                    // base terrain, so a clear would wipe the entire depth buffer AFTER
+                    // player; building interiors through the ground). Outdoors the interiors must
-                    // terrain/exteriors/player drew — the flooded building interiors would
+                    // depth-test against terrain+exteriors and appear only through real door openings,
-                    // paint over everything. Outdoors the interiors must depth-test against
+                    // so issue NO depth clear. Interior roots keep the doorway clear (unchanged).
-                    // terrain+exteriors and appear only through real apertures (the BR-2
+                    ClearDepthSlice = clipRoot.IsOutdoorNode
-                    // commit-2 far-Z punch), so: NO clear, NO seals.
-                    ClearDepthForInterior = clipRoot.IsOutdoorNode
                         ? null
-                        : () =>
+                        : slice =>
                         {
-                            _gl.Disable(EnableCap.ScissorTest);
+                            bool zc = BeginDoorwayScissor(true, slice.NdcAabb);
-                            _gl.DepthMask(true);   // depth clears honor glDepthMask (c4df241 lesson)
                             _gl.Clear(ClearBufferMask.DepthBufferBit);
+                            if (zc)
+                                _gl.Disable(EnableCap.ScissorTest);
                         },
-                    // BR-2: interior roots SEAL exit doors at true depth (#108);
-                    // outdoor roots PUNCH building entry apertures to far-Z so
-                    // flooded interiors show through doorways from outside.
-                    DrawExitPortalMasks = sliceCtx =>
-                        DrawRetailPViewPortalDepthWrite(sliceCtx, envCellViewProj,
-                            forceFarZ: clipRoot.IsOutdoorNode),
                     DrawCellParticles = sliceCtx =>
                         DrawRetailPViewCellParticles(sliceCtx, camera, camPos),
                     EmitDiagnostics = result =>
@@ -7807,11 +7795,6 @@ public sealed class GameWindow : IDisposable
                                 MaxSeedDistance = 48f,
                                 LandblockEntries = _worldState.LandblockEntries,
                                 SetTerrainClipUbo = uboId => _terrain?.SetClipUbo(uboId),
-                                // BR-2: outside-looking-in — PUNCH building entry apertures
-                                // to far-Z so the flooded interior shows through the doorway.
-                                DrawExitPortalMasks = sliceCtx =>
-                                    DrawRetailPViewPortalDepthWrite(sliceCtx, envCellViewProj,
-                                        forceFarZ: true),
                             });
 
                         if (portalResult is not null)
@@ -9567,54 +9550,6 @@ public sealed class GameWindow : IDisposable
         DisableClipDistances();
     }
 
-    // BR-2: retail's invisible portal depth writes on every outside-leading
-    // portal (other_cell_id==0xFFFF) of this cell, clipped to the slice's view
-    // region — D3DPolyRender::DrawPortalPolyInternal (Ghidra 0x0059bc90),
-    // dispatched by PView::DrawCells (Ghidra 0x005a4840). The forceFarZ flag is
-    // retail's maxZ1(true)/maxZ2(false) selector:
-    //
-    //  • INTERIOR root (forceFarZ=false → SEAL, true depth): after the full
-    //    depth clear, stamp the door plane so interior geometry beyond the door
-    //    z-fails inside the aperture and the terrain drawn through the outside
-    //    view keeps its pixels (#108).
-    //  • OUTDOOR root / look-in (forceFarZ=true → PUNCH, far depth): after the
-    //    landscape + shell drew, erase the terrain depth inside the building's
-    //    entry aperture so the flooded interior shows THROUGH the doorway
-    //    against the nearer front-ground. Our pipeline draws the shell FIRST
-    //    (as an outdoor entity in the landscape pass), so — unlike retail's
-    //    shell-LAST order — we get the outside-the-aperture wall occlusion for
-    //    free and need only the punch for in-aperture visibility (no reorder).
-    //
-    // Wiring only — the draw lives in PortalDepthMaskRenderer.
-    private void DrawRetailPViewPortalDepthWrite(
-        AcDream.App.Rendering.RetailPViewCellSliceContext sliceCtx,
-        System.Numerics.Matrix4x4 viewProjection,
-        bool forceFarZ)
-    {
-        if (_portalDepthMask is null)
-            return;
-        if (!_cellVisibility.TryGetCell(sliceCtx.CellId, out var cell) || cell is null)
-            return;
-
-        Span<System.Numerics.Vector3> world = stackalloc System.Numerics.Vector3[32];
-        for (int i = 0; i < cell.Portals.Count; i++)
-        {
-            if (cell.Portals[i].OtherCellId != 0xFFFF)
-                continue;   // depth writes apply to portals leading OUTSIDE only
-            if (i >= cell.PortalPolygons.Count)
-                break;
-            var localVerts = cell.PortalPolygons[i];
-            if (localVerts.Length < 3)
-                continue;
-
-            int n = System.Math.Min(localVerts.Length, world.Length);
-            for (int v = 0; v < n; v++)
-                world[v] = System.Numerics.Vector3.Transform(localVerts[v], cell.WorldTransform);
-
-            _portalDepthMask.DrawDepthFan(world[..n], viewProjection, sliceCtx.Slice.Planes, forceFarZ);
-        }
-    }
-
     private void DrawRetailPViewCellParticles(
         AcDream.App.Rendering.RetailPViewCellSliceContext sliceCtx,
         ICamera camera,
@@ -11838,7 +11773,6 @@ public sealed class GameWindow : IDisposable
         _audioEngine?.Dispose();  // Phase E.2: stop all voices, close AL context
         _wbDrawDispatcher?.Dispose();
         _envCellRenderer?.Dispose();  // Phase A8
-        _portalDepthMask?.Dispose();  // BR-2
         _clipFrame?.Dispose();        // Phase U.3
         _skyRenderer?.Dispose();      // depends on sampler cache; dispose first
         _samplerCache?.Dispose();

src/AcDream.App/Rendering/PortalDepthMaskRenderer.cs

@@ -9,6 +9,18 @@ namespace AcDream.App.Rendering;
 /// writes — the port of <c>D3DPolyRender::DrawPortalPolyInternal</c>
 /// (Ghidra 0x0059bc90, pc:424490).
 ///
+/// <para><b>⚠ RESERVED — NOT wired into the frame as of 2026-06-11.</b> The
+/// first BR-2 attempt wired this as a seal (interior root) + punch (outdoor /
+/// look-in) and was reverted at the visual gate: the outdoor far-Z punch
+/// erased the depth of DYNAMIC objects (player / NPCs) standing in a door
+/// aperture, so the interior painted over them. The gate also proved #108
+/// (cellar grass-sweep) is a MEMBERSHIP bug, not a depth bug — the punch was
+/// only masking it on outdoor-classified cellar frames. The correct depth
+/// discipline (punch → interior → dynamics-last ordering) will be rebuilt
+/// during BR-3 when it can be verified against the shell-chop deletion. This
+/// class is the verified-correct depth-write primitive kept for that work; it
+/// has no callers today.</para>
+///
 /// <para>Retail projects a portal polygon, software-clips it against the
 /// installed portal view (<c>polyClipFinish</c>), and draws the survivor as a
 /// COLOR-INVISIBLE triangle fan with depth-test ALWAYS + depth-write ON:</para>

src/AcDream.App/Rendering/RetailPViewRenderer.cs

@@ -231,16 +231,8 @@ public sealed class RetailPViewRenderer
             ctx.DrawLandscapeSlice(new RetailPViewLandscapeSliceContext(slice, partition.Outdoor));
         }
 
-        // BR-2: retail clears the FULL depth buffer ONCE between the outside
+        foreach (var slice in clipAssembly.OutsideViewSlices)
-        // stage and the interior stage (PView::DrawCells, Ghidra 0x005a4840 —
+            ctx.ClearDepthSlice?.Invoke(slice);
-        // Clear gated on portalsDrawnCount; the exact gate semantics is a plan
-        // open question, staged here as "any outside slice drawn"), then
-        // re-stamps every outside-leading portal's TRUE depth (the seals,
-        // DrawExitPortalMasks below). The old per-slice scissored AABB clear
-        // was the wrong shape (AABB ⊇ aperture polygon) and had no seal after
-        // it — the #108 mechanism.
-        if (clipAssembly.OutsideViewSlices.Length > 0)
-            ctx.ClearDepthForInterior?.Invoke();
 
         UseIndoorMembershipOnlyRouting();
     }
@@ -583,12 +575,7 @@ public sealed class RetailPViewDrawContext : IRetailPViewCellDrawContext
         IReadOnlyDictionary<uint, WorldEntity>? AnimatedById)> LandblockEntries { get; init; }
     public required Action<uint> SetTerrainClipUbo { get; init; }
     public required Action<RetailPViewLandscapeSliceContext> DrawLandscapeSlice { get; init; }
-
+    public Action<ClipViewSlice>? ClearDepthSlice { get; init; }
-    /// <summary>BR-2: one full-buffer depth clear between the outside stage and the
-    /// interior stage (retail PView::DrawCells, Ghidra 0x005a4840). Null for outdoor
-    /// roots — outdoors the interiors must depth-test against terrain + exteriors and
-    /// appear only through real apertures (the BR-2 commit-2 punch).</summary>
-    public Action? ClearDepthForInterior { get; init; }
     public Action<RetailPViewCellSliceContext>? DrawExitPortalMasks { get; init; }
     public Action<RetailPViewCellSliceContext>? DrawCellParticles { get; init; }
     public Action<RetailPViewFrameResult>? EmitDiagnostics { get; init; }