chore(render): S3 landing hygiene — scissor-era dead state, stale comments, the #130 harness, a conjunction-proof weather-gate pin

Chunk H of Campaign OVERHAUL v2's S3 walk-ownership program
(docs/research/2026-09-01-overhaul/s3-walk-ownership-map.md §10.6), landing
the three post-hoc three-lens findings on S3 chunk 4 round 2. Pure dead-state
deletion, comment truth, one test deletion, one stronger pin — no admission,
order, or behavior change; no new flag or probe; no register row (AD-17's
correction is the lead's own, already on the campaign branch).

H1 — ClipPlaneSet.cs: deleted ScissorNdcAabb (no production reader — only
AppendOutsideSlice consumes ClipPlaneSet, and it reads only
IsNothingVisible/Count/PlaneArray) and renamed UseScissorFallback ->
IsPlaneOverflow with a doc stating the true consumer contract: Count==0
overflow means the region draws UNCLIPPED via the no-clip slot, never a
scissor box. Rewrote the file header's convexity-rule and Count==0-states
sections to the two states that exist (Empty / overflow) instead of three,
and simplified the private Scissor(...) AABB-computing helpers into a
parameterless Overflow() factory since nothing reads the AABB any more.
ClipPlaneSetTests.cs: renamed every UseScissorFallback reference, deleted
the AABB assertions (From_MultiplePolygons's four ScissorNdcAabb.X/Y/Z/W
checks, Empty_StaticProperty_DrawsNothing's degenerate-box check,
ScissorFallback_IsNotNothingVisible's bounds check) that pinned the deleted
consumer contract.

H2 — TerrainModernRenderer.cs: deleted Draw's clipPlanes/ndcClipAabb
parameters (grep: TerrainModernRenderer.Draw has exactly one production
caller, WorldScenePassExecutor.DrawFlatTerrain, and it never passed
either), which made CollectVisibleCells's own clipPlanes/ndcClipAabb/
viewProjection parameters and the IsAabbVisibleThroughClipRegion +
IsAabbOutsideHomogeneousPlane helper pair they fed entirely dead — deleted
along with the stale "Retail publishes landcell in_view from the clipped
landscape view" comment; CollectVisibleCells is frustum-only now, matching
DrawLandCells's own "retail never view-clips terrain" doc. Deleted the
terrainUploadCount computation at RetailPViewRenderer.cs (the
DrawInside/DrawLandscapeDynamicsPhase caller) and PrepareClipFrame's
GL-era reservation-count parameter end to end:
IWorldPassSurface.PrepareClipFrame(int), RhiWorldPassSurface's matching
body and its now-pointless "_ = terrainUploadCount" discard,
RetailPViewPassExecutor.PrepareClipFrame's pass-through, and
WorldScenePassExecutor.PrepareFlatWorldClip's hardcoded `1` argument —
PrepareClipFrame() takes nothing on every arm.
TerrainParticleCellVisibilityTests.cs: deleted the three tests that only
existed to pin the removed clip-plane/scissor mechanism
(RejectsCellsOutsideDoorwayClipPlanes, RejectsCellsOutsideDoorwayScissorAabb,
UnionsCellsFromEveryLandscapeSlice) and updated the two surviving frustum
tests to the new signature.

H3 — deleted tests/AcDream.App.Tests/Rendering/Issue130DoorwayStripTests.cs
outright. #130 was a background-color strip along a doorway's top edge from
a since-fixed under-inclusion in the CPU clip pipeline; its scissor half was
already retired at S3 chunk 4 fix round 2 (L7), and its surviving plane-gap
half exercised only PortalVisibilityBuilder.Build and
ClipFrameAssembler.Assemble, both confirmed zero-production-caller legacy
paths (grep) — the one production stage it actually touched,
ClipPlaneSet.From, is already pinned through the real producers
(BeginWalkFrame/ReassembleOutsideViewFromWalk) by the K6/L4 punch-fan
equivalence pin in ClipFrameLayoutTests, so nothing production-relevant lost
coverage.

H4 — comment truth pass:
- ClipFrameAssembler.cs: rewrote the file-header "renderer uses scissor for
  passes that need that fallback" line and the TerrainClipMode summary's
  "that path never produces Scissor" clause. Deleted the TerrainClipMode
  enum's Scissor member — grepped every reader first
  (WorldRenderDiagnostics.cs, WorldSceneDiagnosticsController.cs,
  WorldSceneRendererTests.cs all only pass the value through to a string
  Append or a mock parameter; WorldSceneRenderer.cs, the only writer, sets
  only Planes (default) or Skip, never Scissor) — kept Planes/Skip for the
  flat path and corrected Skip's stale doc ("No outside_view slice is
  visible; skip landscape indoors", a leftover from the pre-round-2 walk
  meaning) to what the flat path's own writer actually means now ("the
  PView walk ran instead of the flat-world path this frame"). Corrected
  ClipViewSlice's doc: the AABB is retained for WorldRenderDiagnostics only,
  not for a scissor consumer.
- WorldPassSurface.cs: "Four concerns... the clip-frame publication, the
  doorway scissor, gl_ClipDistance enablement, and retail's interior depth
  clear" -> three concerns (the doorway scissor was retired at L2), with a
  pointer to ClearInteriorDepth's own truthful doc. EnableClipDistances'
  "all three world vertex shaders already write 1.0" -> only
  portal_depth.vert writes gl_ClipDistance now (grep: sky.vert and
  terrain_modern.vert/terrain_atmospheric.vert no longer declare it at all
  — L3 deleted the block outright; portal_depth.vert still writes 1.0 past
  its active clip count). RhiWorldPassSurface's class doc dropped "the
  scissor is dynamic state on the borrowed encoder" (no producer left).
- RetailPViewPassExecutorTests.cs: DrawLandscapeDynamicsPhase_CallsDraw
  WeatherOnceExactlyOnce's doc corrected "unconditionally" (false since K2)
  to "conditional on WalkFrameDriver.WeatherTurnFired, see the L1 pin".
  Added the switch-table scope note (matching L8's own note on
  DrawWalkSky_RenderSkyCallSiteHasNoEnclosingBackwardBranch) to the K1 pin's
  doc (DrawLandscapeDynamicsPhase_DrawWeatherOnceCallSiteHasNoEnclosing
  BackwardBranch).
- RetailPViewRenderer.cs: the DrawWeatherOnce citation cited the callee
  address (GameSky::Draw(sky,1) @0x00506ff0) where §10.1 cites the call
  site (@0x00506396) — corrected to cite the call site with the callee
  address alongside it.

H5 — MUTATION CHECK (mandatory, run against the production gate at
RetailPViewRenderer.DrawLandscapeDynamicsPhase):
  Added DrawLandscapeDynamicsPhase_ExactlyOneBranchGuardsDrawWeatherOnce,
  which widens the L1 pin's window to start at the
  DrawUnattachedSceneParticles call (the last call before the whole gate)
  and asserts EXACTLY ONE branch total in that window — the L1 pin's own
  window (getter-call to draw-call) misses a conjoined gate's extra,
  earlier condition because that condition's own brfalse lands BEFORE the
  getter call's offset.
  - Mutation 1 (the conjoined gate this pin exists to reject): changed the
    gate to `if (clipAssembly.OutsideViewSlices.Length != 0 &&
    walkDriver.WeatherTurnFired)`, built, ran the new pin — FAILED with:
      Assert.Single() Failure: The collection contained 2 matching items
      Expected:      (predicate expression)
      Collection:    [CompiledBranch { Offset = 7, OpCode = brfalse.s, TargetOffset = 17 }, CompiledBranch { Offset = 24, OpCode = brfalse.s, TargetOffset = 42 }, CompiledBranch { Offset = 33, OpCode = brfalse.s, TargetOffset = 42 }]
      Match indices: 1, 2
    (offset 7 = the DrawUnattachedSceneParticles block's own guard, correctly
    excluded since it precedes that call's offset; offsets 24 and 33 are the
    conjoined gate's two brfalse's, both inside the widened window — exactly
    the failure this pin exists to catch). Restored the single-flag gate;
    rebuilt; the new pin and all 13 sibling tests in
    RetailPViewPassExecutorTests pass again (14/14).
  - Mutation M1 (the existing round-2 regression: restore the pre-fix gate
    `if (clipAssembly.OutsideViewSlices.Length != 0)`), built, ran the full
    suite — the L1 pin
    (DrawLandscapeDynamicsPhase_GatesDrawWeatherOnceOnWalkDriverWeatherTurnFired)
    still FAILS, as required, with:
      Assert.Equal() Failure: Values differ
      Expected: typeof(AcDream.App.Rendering.Walk.WalkFrameDriver)
      Actual:   typeof(AcDream.App.Rendering.ClipFrameAssembly)
    (the new H5 pin does NOT fail under M1 — a single-flag gate still
    produces exactly one branch in the widened window, which is correct:
    catching "wrong condition source" is L1's job, catching "an extra
    conjoined condition" is H5's). Restored the correct gate; rebuilt;
    14/14 green again.

H6 grep sweep (extends §10.5's L6 sweep per the plan):
  grep -rnE "ScissorNdcAabb|UseScissorFallback|TerrainClipMode\.Scissor|ndcClipAabb|terrainUploadCount" --include=*.cs --include=*.vert --include=*.frag src tests
  -> empty (every mention, including in this commit's own explanatory
  comments, was rephrased to avoid the literal deleted identifiers).
  The base L6 sweep (SetTerrainClip|BeginDoorwayScissor|BindTerrainClip|
  TerrainBytes|active scissor|TerrainClipMode\.Scissor|NdcScissorRect) is
  also still empty.

Gates: dotnet build tests/AcDream.App.Tests -c Release -> 0 warnings / 0
errors. Hermetic lane -> 6825/6825 passed, 0 failed. InstalledDat lane
(ACDREAM_DAT_DIR set) -> 243 passed / 4 known failures (2x #383 layout
tests, TowerAscentReplayTests's TowerAscent KnownFailure,
WalkTraceConformanceTests.Oh_doorway_still_first_frame_diff #458
KnownFailure) / 1 skipped / 248 total — one fewer test than before H3, as
expected from Issue130DoorwayStripTests's deletion.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/AcDream.App/Rendering/ClipFrameAssembler.cs

@@ -11,8 +11,9 @@
 //   reverse cell_draw_list object lists
 //
 // Slot 0 is always no-clip. A slice whose polygon cannot be represented by the
-// <=8 plane budget uses slot 0 and its NDC AABB; the renderer uses scissor for
+// <=8 plane budget uses slot 0 too (ClipPlaneSet.IsPlaneOverflow) and draws
-// passes that need that fallback. Empty regions are omitted entirely.
+// unclipped — there is no GPU scissor consumer anywhere in the walk (S3
+// chunk 4 fix round 2, L2). Empty regions are omitted entirely.
 using System.Collections.Generic;
 using System.Numerics;
 
@@ -27,23 +28,25 @@ namespace AcDream.App.Rendering;
 /// <see cref="WorldSceneRenderer"/>'s separate flat-world safety path still
 /// uses it for its own unrelated "did the flat terrain draw this frame"
 /// diagnostic flag (<c>Planes</c> = drew, <c>Skip</c> = the PView walk ran
-/// instead; that path never produces <c>Scissor</c>).
+/// instead). S3 landing hygiene (H4) deleted the <c>Scissor</c> member: no
+/// producer ever wrote it (<see cref="WorldSceneRenderer"/> only ever
+/// assigns <c>Planes</c> or <c>Skip</c>), because there is no GPU scissor
+/// consumer left anywhere in this contract, walk or flat.
 /// </summary>
 public enum TerrainClipMode
 {
-    /// <summary>All outside_view slices have convex plane clips.</summary>
+    /// <summary>The flat-world path drew terrain this frame.</summary>
     Planes,
 
-    /// <summary>At least one outside_view slice requires scissor fallback.</summary>
+    /// <summary>The PView walk ran instead of the flat-world path this frame;
-    Scissor,
+    /// flat terrain was not drawn.</summary>
-
-    /// <summary>No outside_view slice is visible; skip landscape indoors.</summary>
     Skip,
 }
 
 /// <summary>
-/// One retail portal_view slice mapped to a GPU clip slot. The AABB is retained
+/// One retail portal_view slice mapped to a GPU clip slot. The AABB is
-/// for passes that cannot write gl_ClipDistance and must use scissor.
+/// retained for diagnostics (<see cref="WorldRenderDiagnostics"/>) only — no
+/// GPU pass reads it; there is no scissor consumer left in the walk.
 /// </summary>
 public readonly record struct ClipViewSlice(int Slot, Vector4 NdcAabb, Vector4[] Planes);
 

src/AcDream.App/Rendering/ClipPlaneSet.cs

@@ -2,8 +2,8 @@
 //
 // Phase U.2c: turn a CellView (a cell's accumulated screen-space clip region,
 // in NDC) into a small set of clip-space half-space planes for the GPU's
-// gl_ClipDistance, OR a scissor AABB when the region can't be expressed as one
+// gl_ClipDistance, or a signal that the region OVER-includes (draws
-// convex plane set.
+// unclipped) because it cannot be expressed as one convex plane set.
 //
 // This is the bridge between PortalVisibilityBuilder's 2D NDC view polygons and
 // the per-vertex clip the mesh/terrain shaders will perform (Phase U.2c → U.2e).
@@ -20,23 +20,24 @@
 // would clip away the others → a real visibility bug (under-inclusion).
 //
 // Therefore From() NEVER emits a single polygon's planes when the CellView holds
-// several. Multi-polygon (and >8-edge) regions degrade to the UNION AABB scissor:
+// several. Multi-polygon (and >8-edge) regions instead report a plane overflow:
-// the scissor is a superset of the true region, so it OVER-includes (draws a few
+// the consumer (ClipFrameAssembler.AppendOutsideSlice) reads Count == 0 and
-// extra pixels) but never hides anything. Over-inclusion is safe; under-inclusion
+// IsNothingVisible == false, appends an EMPTY plane array (slot 0, no clip), and
-// is the bug class.
+// the polygon draws whole (the punch fan covers the whole fan). That OVER-includes
+// (draws a few extra pixels/triangles) but never hides anything. Over-inclusion is
+// safe; under-inclusion is the bug class. S3 chunk 4 (fix round 2, L2) deleted the
+// only mechanism that ever read a scissor AABB from this type — there is no GPU
+// scissor consumer left anywhere in the walk — so an overflow region simply draws
+// unclipped; it does not carry a bounding box for anyone to scissor against.
 //
-// === The three Count==0 states (how a consumer tells them apart) =============
+// === The two Count==0 states (how a consumer tells them apart) ===============
-// Count == 0 can mean three different things; the consumer MUST distinguish:
+// Count == 0 can mean two different things; the consumer MUST distinguish:
-//   (a) Empty  — IsNothingVisible == true, UseScissorFallback == false.
+//   (a) Empty    — IsNothingVisible == true,  IsPlaneOverflow == false.
-//                The cell/region isn't visible at all → DRAW NOTHING. The
+//                  The cell/region isn't visible at all → DRAW NOTHING.
-//                ScissorNdcAabb is a degenerate inverted box (min > max) so that a
+//   (b) Overflow — IsNothingVisible == false, IsPlaneOverflow == true.
-//                consumer which naively scissors on it still draws nothing.
+//                  The convex-plane budget was exceeded (multi-polygon or >8
-//   (b) Scissor — UseScissorFallback == true, IsNothingVisible == false.
+//                  edges) → DRAW UNCLIPPED (over-include, never a scissor).
-//                The convex-plane budget was exceeded (multi-polygon or >8 edges)
+// When Count > 0, Planes carries the convex gate and both flags above are false.
-//                → DRAW the ScissorNdcAabb box (a valid min<=max NDC rectangle).
-//   There is no third Count==0 state produced by From(). (A separate "no-clip,
-//   pass-all" slot 0 is constructed by the consumer directly, not via From().)
-// When Count > 0, Planes carries the convex gate and the scissor fields are unused.
 using System;
 using System.Buffers;
 using System.Collections.Generic;
@@ -46,8 +47,8 @@ namespace AcDream.App.Rendering;
 
 /// <summary>
 /// An NDC convex view region reduced to ≤8 clip-space gl_ClipDistance planes, or a
-/// scissor AABB fallback. See the file header for the convexity rule and the three
+/// plane-overflow signal (draw unclipped). See the file header for the convexity
-/// Count==0 states.
+/// rule and the two Count==0 states.
 /// </summary>
 public readonly struct ClipPlaneSet
 {
@@ -69,16 +70,15 @@ public readonly struct ClipPlaneSet
     private const float MinPolygonArea = 1e-7f;
     private readonly Vector4[] _planes;
 
-    private ClipPlaneSet(Vector4[] planes, bool useScissorFallback, bool isNothingVisible, Vector4 scissorNdcAabb)
+    private ClipPlaneSet(Vector4[] planes, bool isPlaneOverflow, bool isNothingVisible)
     {
         _planes = planes ?? Array.Empty<Vector4>();
-        UseScissorFallback = useScissorFallback;
+        IsPlaneOverflow = isPlaneOverflow;
         IsNothingVisible = isNothingVisible;
-        ScissorNdcAabb = scissorNdcAabb;
     }
 
-    /// <summary>Number of active clip planes, 0..8. 0 ⇒ inspect <see cref="UseScissorFallback"/>
+    /// <summary>Number of active clip planes, 0..8. 0 ⇒ inspect <see cref="IsPlaneOverflow"/>
-    /// and <see cref="IsNothingVisible"/> to decide between "draw the AABB" and "draw nothing".</summary>
+    /// and <see cref="IsNothingVisible"/> to decide between "draw unclipped" and "draw nothing".</summary>
     public int Count => _planes?.Length ?? 0;
 
     /// <summary>The active clip-space planes (nx, ny, 0, d). Empty when <see cref="Count"/> is 0.
@@ -89,30 +89,26 @@ public readonly struct ClipPlaneSet
     // its frame-scoped slice instead of cloning every plane payload a second time.
     internal Vector4[] PlaneArray => _planes ?? Array.Empty<Vector4>();
 
-    /// <summary>True ⇒ the convex-plane budget was exceeded; gate on <see cref="ScissorNdcAabb"/>
+    /// <summary>True ⇒ Count == 0 because the region needs more than <see cref="MaxPlanes"/>
-    /// instead (draw the box). Always false when <see cref="Count"/> &gt; 0 or when the region is empty.</summary>
+    /// half-planes (or is multi-polygon); the consumer draws UNCLIPPED
-    public bool UseScissorFallback { get; }
+    /// (<c>ClipFrameAssembler.AppendOutsideSlice</c> emits an empty plane array, so the region
+    /// lands on the no-clip slot and — for the punch fans — the fan draws whole) — over-include,
+    /// never a scissor. Always false when <see cref="Count"/> &gt; 0 or when the region is empty.</summary>
+    public bool IsPlaneOverflow { get; }
 
     /// <summary>True ⇒ the region is not visible at all; the consumer draws NOTHING.
-    /// Mutually exclusive with <see cref="UseScissorFallback"/>, and only meaningful when Count == 0.</summary>
+    /// Mutually exclusive with <see cref="IsPlaneOverflow"/>, and only meaningful when Count == 0.</summary>
     public bool IsNothingVisible { get; }
 
-    /// <summary>NDC axis-aligned scissor box (minX, minY, maxX, maxY). Valid (min &lt;= max) only when
+    /// <summary>The "nothing is visible" sentinel: Count == 0, not a plane overflow, draw nothing.</summary>
-    /// <see cref="UseScissorFallback"/> is true. For the empty/nothing-visible case it is a degenerate
-    /// inverted box so naive scissoring still draws nothing.</summary>
-    public Vector4 ScissorNdcAabb { get; }
-
-    /// <summary>The "nothing is visible" sentinel: Count == 0, not a scissor fallback, draw nothing.</summary>
     public static ClipPlaneSet Empty { get; } =
-        new(Array.Empty<Vector4>(), useScissorFallback: false, isNothingVisible: true, scissorNdcAabb: DegenerateAabb);
+        new(Array.Empty<Vector4>(), isPlaneOverflow: false, isNothingVisible: true);
-
-    // Inverted box (min > max) — any sane AABB intersection against it is empty.
-    private static Vector4 DegenerateAabb => new(1f, 1f, -1f, -1f);
 
     /// <summary>
     /// Reduce a CellView's NDC clip region to a ClipPlaneSet. One convex polygon (≤8 edges
-    /// after collinear-merge) → per-edge planes; multi-polygon or >8 edges → union-AABB scissor;
+    /// after collinear-merge) → per-edge planes; multi-polygon or >8 edges → plane overflow
-    /// empty/degenerate → <see cref="Empty"/>. See the file header for the full rule.
+    /// (draw unclipped); empty/degenerate → <see cref="Empty"/>. See the file header for the
+    /// full rule.
     /// </summary>
     public static ClipPlaneSet From(CellView region)
     {
@@ -120,9 +116,8 @@ public readonly struct ClipPlaneSet
             return Empty;
 
         // MORE THAN ONE polygon ⇒ union, not convex ⇒ never emit one polygon's planes.
-        // Over-include via the union AABB (safe). region.Min/Max already track the union.
         if (region.Polygons.Count > 1)
-            return Scissor(region.MinX, region.MinY, region.MaxX, region.MaxY);
+            return Overflow();
 
         return From(region.Polygons[0]);
     }
@@ -152,17 +147,16 @@ public readonly struct ClipPlaneSet
         {
             int count = NormalizeAndMerge(input, verts);
 
-            // Fewer than 3 distinct edges survive ⇒ a sliver/line with no area. There is no
+            // Fewer than 3 distinct edges survive ⇒ a sliver/line with no area ⇒ nothing visible.
-            // meaningful AABB to over-include (a zero-area region), so treat it as nothing visible.
             if (count < 3)
                 return Empty;
 
             ReadOnlySpan<Vector2> normalized = verts[..count];
 
-            // A single convex polygon with too many edges to fit the hardware budget ⇒ scissor
+            // A single convex polygon with too many edges to fit the hardware budget ⇒ plane
-            // on ITS own AABB (still a superset of the polygon → over-include, safe).
+            // overflow (draw unclipped — still a superset of the polygon → over-include, safe).
             if (count > MaxPlanes)
-                return Scissor(normalized);
+                return Overflow();
 
             // 3..8 edges: emit one inward half-space plane per edge (CCW formula). This array is
             // the retained GPU-routing payload and therefore the one necessary allocation.
@@ -179,7 +173,7 @@ public readonly struct ClipPlaneSet
                 //   dist = n.x*clip.x + n.y*clip.y + 0*clip.z + (-(n·p))*clip.w   (>= 0 ⇒ keep)
                 planes[i] = new Vector4(n.X, n.Y, 0f, -Vector2.Dot(n, p));
             }
-            return new ClipPlaneSet(planes, useScissorFallback: false, isNothingVisible: false, scissorNdcAabb: DegenerateAabb);
+            return new ClipPlaneSet(planes, isPlaneOverflow: false, isNothingVisible: false);
         }
         finally
         {
@@ -188,22 +182,8 @@ public readonly struct ClipPlaneSet
         }
     }
 
-    private static ClipPlaneSet Scissor(float minX, float minY, float maxX, float maxY) =>
+    private static ClipPlaneSet Overflow() =>
-        new(Array.Empty<Vector4>(), useScissorFallback: true, isNothingVisible: false,
+        new(Array.Empty<Vector4>(), isPlaneOverflow: true, isNothingVisible: false);
-            scissorNdcAabb: new Vector4(minX, minY, maxX, maxY));
-
-    private static ClipPlaneSet Scissor(ReadOnlySpan<Vector2> verts)
-    {
-        float minX = float.MaxValue, minY = float.MaxValue, maxX = float.MinValue, maxY = float.MinValue;
-        foreach (var v in verts)
-        {
-            if (v.X < minX) minX = v.X;
-            if (v.X > maxX) maxX = v.X;
-            if (v.Y < minY) minY = v.Y;
-            if (v.Y > maxY) maxY = v.Y;
-        }
-        return Scissor(minX, minY, maxX, maxY);
-    }
 
     /// <summary>
     /// Return the polygon wound CCW with collinear vertices removed. The PortalVisibilityBuilder

src/AcDream.App/Rendering/RetailPViewPassExecutor.cs

@@ -140,8 +140,8 @@ public RetailPViewPassExecutor(
         ClipFrameAssembly reuseAssembly) =>
         ClipFrameAssembler.BeginWalkFrame(_clipFrame, outdoorRoot, reuseAssembly);
 
-    public void PrepareClipFrame(int terrainUploadCount) =>
+    public void PrepareClipFrame() =>
-        _surface.PrepareClipFrame(terrainUploadCount);
+        _surface.PrepareClipFrame();
 
     public void PrepareCellBatches(
         RetailPViewFrameInput frame,

src/AcDream.App/Rendering/RetailPViewRenderer.cs

@@ -413,10 +413,11 @@ internal sealed class RetailPViewRenderer
 
         // FW4 slice 1: the ONE clip-region publication, after any walk
         // reassembly so the walk-derived outside-view slots are included
-        // (moved from directly after AssembleClipFrame; the count is
+        // (moved from directly after AssembleClipFrame). S3 landing hygiene
-        // reservation metadata the RHI arm ignores).
+        // (H2) deleted the GL-era arena-reservation count this call used to
-        int terrainUploadCount = checked(1 + clipAssembly.OutsideViewSlices.Length * 2);
+        // compute and pass — PrepareClipFrame() takes nothing now (see
-        passes.PrepareClipFrame(terrainUploadCount);
+        // IWorldPassSurface.PrepareClipFrame's doc).
+        passes.PrepareClipFrame();
 
         // Production prepares exactly the one walk's visited-cell set.
         HashSet<uint> prepareCells = drawableCells;
@@ -643,8 +644,9 @@ internal sealed class RetailPViewRenderer
         // + DrawLandscapeSliceLate, one call per active landscape view) is
         // DELETED — retail draws the
         // weather mesh and its rain particles ONCE, unclipped, after
-        // LScape::draw's whole landblock loop (GameSky::Draw(sky,1)
+        // LScape::draw's whole landblock loop (GameSky::Draw(sky,1) call site
-        // @0x00506ff0), never once per doorway aperture. DrawWeatherOnce
+        // @0x00506396 — the callee itself is @0x00506ff0), never once per
+        // doorway aperture. DrawWeatherOnce
         // is the ONE call that remains — it now also submits the rain
         // particles (moved from the deleted loop's per-slice, per-doorway
         // ParticleRenderPass.SkyPostScene draw) as ONE unclipped

src/AcDream.App/Rendering/TerrainModernRenderer.cs

@@ -241,8 +241,6 @@ public sealed partial class TerrainModernRenderer : IDisposable
         ICamera camera,
         FrustumPlanes? frustum = null,
         uint? neverCullLandblockId = null,
-        ReadOnlySpan<Vector4> clipPlanes = default,
-        Vector4? ndcClipAabb = null,
         IReadOnlySet<uint>? inViewLandcells = null)
     {
         if (_alloc.LoadedCount == 0) return;
@@ -289,10 +287,7 @@ public sealed partial class TerrainModernRenderer : IDisposable
                     data.WorldOrigin,
                     data.AabbMin.Z,
                     data.AabbMax.Z,
-                    frustum,
+                    frustum);
-                    viewProjection,
-                    clipPlanes,
-                    ndcClipAabb);
             }
         }
         if (_visibleSlots.Count == 0) return;
@@ -485,16 +480,23 @@ public sealed partial class TerrainModernRenderer : IDisposable
     // Private helpers
     // ----------------------------------------------------------------
 
+    /// <summary>
+    /// S3 landing hygiene (H2): frustum-only now. Retail never view-clips
+    /// terrain (see <see cref="DrawLandCells"/>'s doc); the CPU/GPU
+    /// clip-region equivalence check this used to also run (a doorway
+    /// slice's clip-space planes plus its NDC-AABB scissor fallback) had
+    /// exactly one caller — <see cref="Draw"/> — and that caller's own two
+    /// clip-region parameters were themselves dead (grep: no production
+    /// caller ever passed either), so the equivalence helper and its
+    /// homogeneous-plane subroutine are deleted along with them.
+    /// </summary>
     internal static void CollectVisibleCells(
         HashSet<uint> destination,
         uint landblockId,
         Vector3 worldOrigin,
         float zMin,
         float zMax,
-        FrustumPlanes? frustum,
+        FrustumPlanes? frustum)
-        Matrix4x4 viewProjection,
-        ReadOnlySpan<Vector4> clipPlanes,
-        Vector4? ndcClipAabb = null)
     {
         ArgumentNullException.ThrowIfNull(destination);
         const float cellSize = AcDream.Core.Physics.TerrainSurface.CellSize;
@@ -517,21 +519,6 @@ public sealed partial class TerrainModernRenderer : IDisposable
                     continue;
                 }
 
-                // Retail publishes landcell in_view from the clipped landscape
-                // view, not merely from the camera frustum. The modern renderer
-                // expresses each doorway slice as homogeneous clip-space planes
-                // plus its scissor AABB; use both products here so particle
-                // simulation follows the same visible terrain slice as the GPU.
-                if (!IsAabbVisibleThroughClipRegion(
-                        cellMin,
-                        cellMax,
-                        viewProjection,
-                        clipPlanes,
-                        ndcClipAabb))
-                {
-                    continue;
-                }
-
                 uint low = AcDream.Core.Physics.TerrainSurface.ComputeOutdoorCellLowId(
                     cellX * cellSize,
                     cellY * cellSize);
@@ -540,75 +527,6 @@ public sealed partial class TerrainModernRenderer : IDisposable
         }
     }
 
-    private static bool IsAabbVisibleThroughClipRegion(
-        Vector3 min,
-        Vector3 max,
-        Matrix4x4 viewProjection,
-        ReadOnlySpan<Vector4> clipPlanes,
-        Vector4? ndcClipAabb)
-    {
-        Vector4 aabb = ndcClipAabb.GetValueOrDefault();
-        bool hasScissorConstraint = ndcClipAabb.HasValue
-            && (aabb.X > -1f || aabb.Y > -1f || aabb.Z < 1f || aabb.W < 1f);
-        if (clipPlanes.IsEmpty && !hasScissorConstraint)
-            return true;
-
-        Span<Vector4> clipCorners = stackalloc Vector4[8];
-        for (int corner = 0; corner < clipCorners.Length; corner++)
-        {
-            var world = new Vector4(
-                (corner & 1) == 0 ? min.X : max.X,
-                (corner & 2) == 0 ? min.Y : max.Y,
-                (corner & 4) == 0 ? min.Z : max.Z,
-                1f);
-            clipCorners[corner] = Vector4.Transform(world, viewProjection);
-        }
-
-        for (int planeIndex = 0; planeIndex < clipPlanes.Length; planeIndex++)
-        {
-            if (IsAabbOutsideHomogeneousPlane(clipCorners, clipPlanes[planeIndex]))
-            {
-                return false;
-            }
-        }
-
-        if (!hasScissorConstraint)
-            return true;
-
-        Span<Vector4> scissorPlanes = stackalloc Vector4[4]
-        {
-            new( 1f,  0f, 0f, -aabb.X),
-            new(-1f,  0f, 0f,  aabb.Z),
-            new( 0f,  1f, 0f, -aabb.Y),
-            new( 0f, -1f, 0f,  aabb.W),
-        };
-        for (int planeIndex = 0; planeIndex < scissorPlanes.Length; planeIndex++)
-        {
-            if (IsAabbOutsideHomogeneousPlane(clipCorners, scissorPlanes[planeIndex]))
-            {
-                return false;
-            }
-        }
-
-        return true;
-    }
-
-    private static bool IsAabbOutsideHomogeneousPlane(
-        ReadOnlySpan<Vector4> clipCorners,
-        Vector4 plane)
-    {
-        // A linear half-space reaches its maximum over the transformed AABB at
-        // one of the eight corners. If every corner is negative, no point in
-        // the cell box can survive this GPU clip plane.
-        for (int corner = 0; corner < clipCorners.Length; corner++)
-        {
-            if (Vector4.Dot(plane, clipCorners[corner]) >= 0f)
-                return false;
-        }
-
-        return true;
-    }
-
     private void EnsureCapacity(int newCapacity)
     {
         if (newCapacity <= _alloc.Capacity)

src/AcDream.App/Rendering/WorldPassSurface.cs

@@ -20,10 +20,12 @@ internal interface IRenderFrameGlState
 /// and heavily tested — is written once for both backends.
 ///
 /// <para>Everything else those executors do is delegation to a renderer. What is
-/// left is exactly this: the clip-frame publication, the doorway scissor,
+/// left is exactly this: the clip-frame publication, <c>gl_ClipDistance</c>
-/// <c>gl_ClipDistance</c> enablement, and retail's interior depth clear. Four
+/// enablement, and retail's interior depth clear. Three concerns, each of
-/// concerns, each of which genuinely differs between GL and Vulkan, and none of
+/// which genuinely differs between GL and Vulkan, and none of which is
-/// which is expressible on the pinned RHI contract.</para>
+/// expressible on the pinned RHI contract. (S3 landing hygiene, H4: the
+/// doorway scissor this used to also cover was retired at S3 chunk 4 fix
+/// round 2 — see <see cref="ClearInteriorDepth"/>'s implementation doc.)</para>
 /// </summary>
 internal interface IWorldPassSurface
 {
@@ -31,13 +33,6 @@ internal interface IWorldPassSurface
     /// Publishes this frame's per-cell clip-region table, and routes it to the
     /// renderers that read it.
     ///
-    /// <para><paramref name="terrainUploadCount"/> is how many distinct terrain
-    /// clip blocks the frame will issue. GL reserves that many arena records
-    /// before the first draw, because reallocating the arena while an earlier
-    /// slice can still reference it is the hazard the reservation exists for. The
-    /// RHI arm ignores it: a ring allocation is distinct memory by construction
-    /// and lives until the frame retires.</para>
-    ///
     /// <para>S3 chunk 4 fix round 1 (K3) deleted the walk's per-frame terrain
     /// screen-space clip publish this used to also carry — its only writer
     /// was retired along with the per-outside-view-slice terrain/sky/weather
@@ -45,17 +40,29 @@ internal interface IWorldPassSurface
     /// declaration of that clip block along with the section binder that used
     /// to re-assert it, so this contract now publishes exactly one section,
     /// the per-cell clip-region table.</para>
+    ///
+    /// <para>S3 landing hygiene (H2) deleted the GL-era reservation-count
+    /// parameter this used to also take (how many distinct terrain clip
+    /// blocks the frame would issue): the RHI arm always ignored it (a ring
+    /// allocation is distinct memory by construction and lives until the
+    /// frame retires), and the last GL implementation that read it
+    /// (<c>GlWorldPassSurface</c>) was deleted at Campaign V slice V11 —
+    /// nothing was left to size a reservation for.</para>
     /// </summary>
-    void PrepareClipFrame(int terrainUploadCount);
+    void PrepareClipFrame();
 
     /// <summary>
     /// Enables every <c>gl_ClipDistance</c> slot.
     ///
     /// <para>Vulkan activates every element the shader declares and has no
     /// enable, so this is a no-op there — and that is safe rather than a
-    /// divergence: all three world vertex shaders already write <c>1.0</c>
+    /// divergence: only <c>portal_depth.vert</c> writes <c>gl_ClipDistance</c>
-    /// ("keep everything") into every slot past the active count, so a frame with
+    /// in the world pass now (S3 landing hygiene, H4 — S3 chunk 4 fix round 2
-    /// no clip planes clips nothing on either backend (plan §5.5.14 item 4).</para>
+    /// (L3) deleted the sky and terrain shaders' own declaration of the block
+    /// this contract used to also publish; see <see cref="PrepareClipFrame"/>'s
+    /// doc). It still writes <c>1.0</c> ("keep everything") into every slot
+    /// past its active count, so a frame with no clip planes clips nothing on
+    /// either backend (plan §5.5.14 item 4).</para>
     /// </summary>
     void EnableClipDistances();
 
@@ -73,11 +80,10 @@ internal interface IWorldPassSurface
 }
 
 /// <summary>
-/// The clip tables are ring sections published on the world pass scope, the
+/// The clip table is a ring section published on the world pass scope, and the
-/// scissor is dynamic state on the borrowed encoder, and the depth clear is a
+/// depth clear is a scoped <c>vkCmdClearAttachments</c>. The raw-GL
-/// scoped <c>vkCmdClearAttachments</c>. The raw-GL implementation this used to
+/// implementation this used to sit alongside (<c>GlWorldPassSurface</c>) was
-/// sit alongside (<c>GlWorldPassSurface</c>) was deleted at Campaign V slice
+/// deleted at Campaign V slice V11.
-/// V11.
 /// </summary>
 internal sealed class RhiWorldPassSurface : IWorldPassSurface
 {
@@ -95,12 +101,8 @@ internal sealed class RhiWorldPassSurface : IWorldPassSurface
         _clipFrame = clipFrame ?? throw new ArgumentNullException(nameof(clipFrame));
     }
 
-    public void PrepareClipFrame(int terrainUploadCount)
+    public void PrepareClipFrame()
     {
-        // The reservation count has no RHI counterpart: each publication below
-        // takes its own ring slice, which is distinct memory that outlives every
-        // draw recorded against it in this frame.
-        _ = terrainUploadCount;
         _scope.Sections.ClipRegions = Publish(
             _clipFrame.RegionBytes,
             GpuRingUsage.Storage);

src/AcDream.App/Rendering/WorldScenePassExecutor.cs

@@ -110,7 +110,7 @@ internal sealed class WorldScenePassExecutor : IWorldScenePassExecutor
         _environmentCells.SetClipRouting(null);
     }
 
-    public void PrepareFlatWorldClip() => _surface.PrepareClipFrame(1);
+    public void PrepareFlatWorldClip() => _surface.PrepareClipFrame();
 
     public void DrawFlatSky(
         in WorldCameraFrame camera,

tests/AcDream.App.Tests/Rendering/ClipPlaneSetTests.cs

@@ -47,9 +47,8 @@ public class ClipPlaneSetTests
         var fromPolygon = ClipPlaneSet.From(polygon);
 
         Assert.Equal(fromView.Count, fromPolygon.Count);
-        Assert.Equal(fromView.UseScissorFallback, fromPolygon.UseScissorFallback);
+        Assert.Equal(fromView.IsPlaneOverflow, fromPolygon.IsPlaneOverflow);
         Assert.Equal(fromView.IsNothingVisible, fromPolygon.IsNothingVisible);
-        Assert.Equal(fromView.ScissorNdcAabb, fromPolygon.ScissorNdcAabb);
         Assert.Equal(fromView.Planes, fromPolygon.Planes);
     }
 
@@ -75,14 +74,14 @@ public class ClipPlaneSetTests
     }
 
     [Fact]
-    public void From_NineEdgePolygon_FallsBackToScissor()
+    public void From_NineEdgePolygon_FallsBackToPlaneOverflow()
     {
         var poly = RegularNgonCellView(n: 9, radius: 0.6f);
         var cps = ClipPlaneSet.From(poly);
-        Assert.True(cps.UseScissorFallback || cps.Count <= 8);
+        Assert.True(cps.IsPlaneOverflow || cps.Count <= 8);
-        if (cps.UseScissorFallback)
+        if (cps.IsPlaneOverflow)
         {
-            Assert.Equal(0, cps.Count); // AABB carries the gate
+            Assert.Equal(0, cps.Count); // draws unclipped, no plane gate
         }
     }
 
@@ -95,7 +94,7 @@ public class ClipPlaneSetTests
     // --- Multi-polygon safety (the under-inclusion guard) ---------------------
 
     [Fact]
-    public void From_MultiplePolygons_FallsBackToUnionScissor_NeverEmitsOnePolygonsPlanes()
+    public void From_MultiplePolygons_FallsBackToPlaneOverflow_NeverEmitsOnePolygonsPlanes()
     {
         // Two disjoint squares: a CONVEX plane set can never represent their union.
         var cv = new CellView();
@@ -111,29 +110,19 @@ public class ClipPlaneSetTests
         var cps = ClipPlaneSet.From(cv);
 
         // MUST NOT emit a single polygon's convex planes (that would hide the other).
-        Assert.True(cps.UseScissorFallback);
+        Assert.True(cps.IsPlaneOverflow);
         Assert.Equal(0, cps.Count);
         Assert.Empty(cps.Planes);
-
-        // Scissor AABB is the UNION of both polygons (over-include, safe).
-        Assert.Equal(-0.8f, cps.ScissorNdcAabb.X, 5); // minX
-        Assert.Equal(-0.8f, cps.ScissorNdcAabb.Y, 5); // minY
-        Assert.Equal(0.8f, cps.ScissorNdcAabb.Z, 5);  // maxX
-        Assert.Equal(0.8f, cps.ScissorNdcAabb.W, 5);  // maxY
-
-        // The far corner of the second square is inside the union AABB → not hidden.
-        Assert.True(0.7f >= cps.ScissorNdcAabb.X && 0.7f <= cps.ScissorNdcAabb.Z);
-        Assert.True(0.7f >= cps.ScissorNdcAabb.Y && 0.7f <= cps.ScissorNdcAabb.W);
     }
 
-    // --- Distinguishing the three Count==0 states ----------------------------
+    // --- Distinguishing the two Count==0 states -------------------------------
 
     [Fact]
-    public void Empty_IsNothingVisible_NotScissorFallback()
+    public void Empty_IsNothingVisible_NotPlaneOverflow()
     {
         var e = ClipPlaneSet.From(new CellView());
         Assert.Equal(0, e.Count);
-        Assert.False(e.UseScissorFallback);   // NOT "draw the AABB box"
+        Assert.False(e.IsPlaneOverflow);       // NOT "draws unclipped"
         Assert.True(e.IsNothingVisible);       // "draw nothing"
         Assert.Empty(e.Planes);
     }
@@ -143,23 +132,17 @@ public class ClipPlaneSetTests
     {
         var e = ClipPlaneSet.Empty;
         Assert.Equal(0, e.Count);
-        Assert.False(e.UseScissorFallback);
+        Assert.False(e.IsPlaneOverflow);
         Assert.True(e.IsNothingVisible);
-        // Degenerate AABB (min > max) so a consumer that naively scissors on it draws nothing.
-        Assert.True(e.ScissorNdcAabb.X > e.ScissorNdcAabb.Z);
-        Assert.True(e.ScissorNdcAabb.Y > e.ScissorNdcAabb.W);
     }
 
     [Fact]
-    public void ScissorFallback_IsNotNothingVisible()
+    public void PlaneOverflow_IsNotNothingVisible()
     {
         var poly = RegularNgonCellView(n: 9, radius: 0.6f);
         var cps = ClipPlaneSet.From(poly);
-        Assert.True(cps.UseScissorFallback);
+        Assert.True(cps.IsPlaneOverflow);
-        Assert.False(cps.IsNothingVisible); // "draw the AABB box", not "draw nothing"
+        Assert.False(cps.IsNothingVisible); // "draws unclipped", not "draw nothing"
-        // The fallback AABB bounds the 9-gon (radius 0.6).
-        Assert.True(cps.ScissorNdcAabb.Z - cps.ScissorNdcAabb.X > 0.5f);
-        Assert.True(cps.ScissorNdcAabb.W - cps.ScissorNdcAabb.Y > 0.5f);
     }
 
     // --- Plane-sign correctness for every edge -------------------------------
@@ -242,13 +225,13 @@ public class ClipPlaneSetTests
         Assert.Equal(4, cps.Count); // the redundant collinear edge is merged away
     }
 
-    // --- Exactly 8 edges fit (octagon); 9 spills to scissor (after merge fails to help).
+    // --- Exactly 8 edges fit (octagon); 9 spills to plane overflow (after merge fails to help).
 
     [Fact]
     public void From_RegularOctagon_FitsInEightPlanes()
     {
         var cps = ClipPlaneSet.From(RegularNgonCellView(n: 8, radius: 0.6f));
-        Assert.False(cps.UseScissorFallback);
+        Assert.False(cps.IsPlaneOverflow);
         Assert.Equal(8, cps.Count);
         var center = new Vector4(0, 0, 0, 1);
         foreach (var p in cps.Planes)

tests/AcDream.App.Tests/Rendering/Issue130DoorwayStripTests.cs

@@ -1,326 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Numerics;
-using AcDream.App.Rendering;
-using DatReaderWriter;
-using DatReaderWriter.Options;
-using Xunit;
-using Xunit.Abstractions;
-
-namespace AcDream.App.Tests.Rendering;
-
-/// <summary>
-/// #130 — background-color strip along the TOP outer edge of a doorway when
-/// looking out from inside. Mechanism model (2026-06-12 evidence sweep): for
-/// an interior root the SEAL stamps the FULL raw dat portal polygon at true
-/// depth (PortalDepthMaskRenderer, root-cell slice = full screen), while
-/// terrain/sky COLOR used to be gated per fragment by the OutsideView region —
-/// the same dat polygon run through ProjectToClip → ClipToRegion (1-px
-/// MergeSubPixelVertices) → ClipPlaneSet.From (0.5° collinear merge) → planes,
-/// with a Floor/Ceil pixel scissor (the sky's own doorway scissor bracket)
-/// on the slice AABB on top. Every one of those passes could only SHRINK the gate, so any
-/// shave showed as a strip of clear color between the gate's top edge and the
-/// aperture's rasterized top edge.
-///
-/// RETIRED MECHANISM (S3 chunk 4 fix round 2, L7): the scissor half of this
-/// story no longer applies. Retail draws the sky and the landscape unclipped
-/// (<c>LScape::draw</c> never installs a view before either — S3 chunk 3/4's
-/// own findings), and acdream now matches that: the sky's own doorway
-/// scissor bracket, <c>IWorldPassSurface.BeginScissor/EndScissor</c>, and
-/// every per-slice terrain/sky/weather clip they used to bracket are deleted
-/// outright. An
-/// interior root's aperture exactness comes instead from the depth clear, the
-/// exit seals, and the interior repaint (<c>WalkFrameDriver</c>'s interior
-/// turn draws the real cell geometry back over whatever the unclipped
-/// landscape painted through the doorway) — see the S3 chunk 4 plan section
-/// for the retail citations.
-///
-/// What remains below still pins something production reads: the outside-view
-/// polygon pipeline (<c>ProjectToClip</c> → <c>ClipToRegion</c> →
-/// <c>ClipPlaneSet.From</c>) that the KEPT punch-fan clip still consumes
-/// (<c>RetailPViewPassExecutor.DrawWalkPunchFan</c> reads
-/// <c>clipAssembly.OutsideViewSlices[activeViewIndex].Planes</c> — see
-/// <c>ClipFrameLayoutTests</c>'s punch-fan equivalence pin for the synthetic-
-/// view version of this same proof). This harness measures the PLANE gap
-/// headlessly at the real Holtburg corner building exit door (A9B4 0x0170,
-/// the HouseExitWalkReplay door): project the aperture, run the production
-/// flood + assembler, then walk sample points just inside the aperture's top
-/// edge downward until the plane gate admits them.
-///
-/// VERDICT (2026-06-12, 147 eye/gaze combos, plane half only — the original
-/// sweep also measured a scissor gap, since retired): the CPU polygon
-/// pipeline is sub-pixel exact (worst 0.54 px) — the W=0 clip port 987313a
-/// and both merge passes are EXONERATED. PIN 2 below still asserts that
-/// bound.
-/// </summary>
-[Trait("Lane", "InstalledDat")]
-public class Issue130DoorwayStripTests
-{
-    private readonly ITestOutputHelper _out;
-    public Issue130DoorwayStripTests(ITestOutputHelper output) => _out = output;
-
-    private const uint ExitCellId = CornerFloodReplayTests.Landblock | 0x0170u;
-
-    // Production projection convention (CornerFloodReplayTests.ViewProjFor):
-    // FovY 1.2 rad, 1280x720 viewport, near 1, far 5000. The flood clip is
-    // near-independent so near/far exactness is not load-bearing.
-    private static Matrix4x4 ViewProjFor(Vector3 eye, Vector3 lookAt)
-    {
-        var view = Matrix4x4.CreateLookAt(eye, lookAt, Vector3.UnitZ);
-        var proj = Matrix4x4.CreatePerspectiveFieldOfView(1.2f, 1280f / 720f, 1f, 5000f);
-        return view * proj;
-    }
-
-    [Fact]
-    public void ExitDoorTopEdge_GateCoversTheDrawnApertureWithinPixelTolerance()
-    {
-        var datDir = CornerFloodReplayTests.ResolveDatDir();
-        if (datDir is null) { _out.WriteLine("SKIP: dats unavailable"); Assert.Fail("Lane=InstalledDat requires an installed retail DAT directory; see docs/release-gate.md."); }
-
-        using var dats = new DatCollection(datDir, DatAccessType.Read);
-        var cells = CornerFloodReplayTests.LoadBuilding(dats);
-        var root = cells[ExitCellId];
-        LoadedCell? Lookup(uint id) => cells.TryGetValue(id, out var c) ? c : null;
-
-        // Find the exit portal (OtherCellId == 0xFFFF) and its world polygon.
-        int exitIdx = -1;
-        for (int i = 0; i < root.Portals.Count; i++)
-        {
-            if (root.Portals[i].OtherCellId == 0xFFFF && i < root.PortalPolygons.Count
-                && root.PortalPolygons[i].Length >= 3)
-            { exitIdx = i; break; }
-        }
-        Assert.True(exitIdx >= 0, "0x0170 has no exit portal polygon");
-
-        var localPoly = root.PortalPolygons[exitIdx];
-        // Campaign FW3.3: ShellDrawLiftZ is retired — shells, seal fans, and
-        // the gate all live in the ONE dat space, so the drawn aperture IS
-        // the physics polygon. This test survives as the coverage proof
-        // (gate covers the drawn hole within tolerance across the sweep);
-        // the historical lifted-vs-unlifted strip test's premise (two
-        // spaces) no longer exists and that test is deleted.
-        var worldPoly = new Vector3[localPoly.Length];
-        for (int i = 0; i < localPoly.Length; i++)
-            worldPoly[i] = Vector3.Transform(localPoly[i], root.WorldTransform);
-
-        Vector3 centroid = Vector3.Zero;
-        foreach (var w in worldPoly) centroid += w;
-        centroid /= worldPoly.Length;
-
-        // Inward direction: the portal plane normal signed toward the cell
-        // interior (ClipPlanes carries InsideSide from the load).
-        var plane = root.ClipPlanes[exitIdx];
-        var worldNormal = Vector3.TransformNormal(plane.Normal, root.WorldTransform);
-        var cellCenterWorld = Vector3.Transform(
-            (root.LocalBoundsMin + root.LocalBoundsMax) * 0.5f, root.WorldTransform);
-        if (Vector3.Dot(worldNormal, cellCenterWorld - centroid) < 0)
-            worldNormal = -worldNormal;
-        worldNormal = Vector3.Normalize(worldNormal);
-
-        _out.WriteLine(FormattableString.Invariant(
-            $"exit portal idx={exitIdx} verts={localPoly.Length} centroid=({centroid.X:F2},{centroid.Y:F2},{centroid.Z:F2}) inward=({worldNormal.X:F2},{worldNormal.Y:F2},{worldNormal.Z:F2})"));
-        for (int i = 0; i < worldPoly.Length; i++)
-            _out.WriteLine(FormattableString.Invariant(
-                $"  poly[{i}] world=({worldPoly[i].X:F3},{worldPoly[i].Y:F3},{worldPoly[i].Z:F3})"));
-
-        float worstPlaneGapPx = 0f;
-        string worstDesc = "(none)";
-
-        // Eye sweep: back off the doorway along the inward normal at several
-        // distances/heights/lateral offsets; gaze at the centroid plus raised /
-        // lowered targets (NDC alignment of the top edge varies with gaze).
-        var lateral = Vector3.Normalize(Vector3.Cross(worldNormal, Vector3.UnitZ));
-        float[] dists = { 0.6f, 1.0f, 1.6f, 2.4f, 3.5f };
-        float[] heights = { 0.9f, 1.4f, 1.7f };
-        float[] laterals = { -0.8f, 0f, 0.8f };
-        float[] gazeRaise = { -0.4f, 0f, 0.4f, 0.9f };
-
-        int evaluated = 0;
-        foreach (float d in dists)
-        foreach (float h in heights)
-        foreach (float lat in laterals)
-        foreach (float gz in gazeRaise)
-        {
-            var eye = centroid + worldNormal * d + lateral * lat;
-            eye.Z = centroid.Z - 1.0f + h; // door centroid sits mid-opening; bias to floor-ish
-            var look = centroid + new Vector3(0, 0, gz);
-            var viewProj = ViewProjFor(eye, look);
-
-            // Aperture truth: the seal's footprint = the raw polygon's projection.
-            var clip = new Vector4[worldPoly.Length];
-            float minW = float.MaxValue;
-            for (int i = 0; i < worldPoly.Length; i++)
-            {
-                clip[i] = Vector4.Transform(new Vector4(worldPoly[i], 1f), viewProj);
-                minW = MathF.Min(minW, clip[i].W);
-            }
-            if (minW <= 0.05f) continue; // eye in/behind the door plane — out of #130's scenario
-            var aperture = new Vector2[clip.Length];
-            for (int i = 0; i < clip.Length; i++)
-                aperture[i] = new Vector2(clip[i].X / clip[i].W, clip[i].Y / clip[i].W);
-
-            var pv = PortalVisibilityBuilder.Build(root, eye, Lookup, viewProj,
-                buildingMembership: null);
-            var asm = ClipFrameAssembler.Assemble(ClipFrame.NoClip(), pv);
-            if (asm.OutsideViewSlices.Length == 0)
-            {
-                _out.WriteLine(FormattableString.Invariant(
-                    $"d={d} h={h} lat={lat} gz={gz}: NO outside slice (outPolys={pv.OutsideView.Polygons.Count})"));
-                continue;
-            }
-            evaluated++;
-
-            (float planeGapPx, float atX) =
-                MeasureTopEdgeGap(aperture, asm.OutsideViewSlices, 1080);
-
-            if (planeGapPx > worstPlaneGapPx)
-            {
-                worstDesc = FormattableString.Invariant(
-                    $"d={d} h={h} lat={lat} gz={gz} minW={minW:F2} atX={atX:F3} slices={asm.OutsideViewSlices.Length} outVerts={DescribePolys(pv.OutsideView)} apVerts={aperture.Length}");
-                worstPlaneGapPx = planeGapPx;
-            }
-
-            if (planeGapPx > 0.55f)
-            {
-                _out.WriteLine(FormattableString.Invariant(
-                    $"GAP d={d} h={h} lat={lat} gz={gz}: planeGap={planeGapPx:F2}px atX={atX:F3} outVerts={DescribePolys(pv.OutsideView)}"));
-                float apTop = TopBoundaryY(aperture, atX);
-                foreach (var slice in asm.OutsideViewSlices)
-                    _out.WriteLine(FormattableString.Invariant(
-                        $"  slice slot={slice.Slot} planes={slice.Planes.Length} aabb=({slice.NdcAabb.X:F4},{slice.NdcAabb.Y:F4},{slice.NdcAabb.Z:F4},{slice.NdcAabb.W:F4}) apTopAtX={apTop:F4}"));
-                foreach (var poly in pv.OutsideView.Polygons)
-                {
-                    var sb = new System.Text.StringBuilder("  outPoly:");
-                    foreach (var v in poly.Vertices)
-                        sb.Append(FormattableString.Invariant($" ({v.X:F4},{v.Y:F4})"));
-                    _out.WriteLine(sb.ToString());
-                }
-            }
-        }
-
-        _out.WriteLine(FormattableString.Invariant(
-            $"evaluated={evaluated} worstPlaneGapPx={worstPlaneGapPx:F2} @ {worstDesc}"));
-
-        Assert.True(evaluated > 100, $"sweep degenerated: only {evaluated} eye/gaze combos evaluated");
-        // PIN (canary): the CPU polygon pipeline (ProjectToClip → ClipToRegion
-        // merges → ClipPlaneSet planes) stays sub-pixel exact against the raw
-        // aperture projection. Observed 0.54 px worst (2026-06-12); the
-        // production vertex-merge floor is ~1 px — beyond 1.2 px means a new
-        // under-inclusion shaver entered the pipeline.
-        Assert.True(worstPlaneGapPx <= 1.2f, FormattableString.Invariant(
-            $"plane gate under-covers the aperture top edge by {worstPlaneGapPx:F2}px @ {worstDesc}"));
-    }
-
-    private static string DescribePolys(CellView view)
-    {
-        var parts = new List<string>();
-        foreach (var p in view.Polygons) parts.Add(p.Vertices.Length.ToString());
-        return $"[{string.Join(",", parts)}]";
-    }
-
-    /// <summary>
-    /// For sample x positions across the aperture's projected top edge, find the
-    /// aperture boundary's top y, then walk downward until the plane gate
-    /// admits the point. Returns the worst gap in 1080p pixels, and the x of
-    /// the worst gap. S3 chunk 4 fix round 2 (L7): the scissor-gap half this
-    /// used to measure alongside the plane gap is deleted — the scissor
-    /// mechanism it modeled no longer exists in production.
-    /// </summary>
-    private static (float planeGapPx, float atX) MeasureTopEdgeGap(
-        Vector2[] aperture, ClipViewSlice[] slices, int fbH,
-        ITestOutputHelper? debug = null)
-    {
-        const float Inset = 1e-4f;   // dodge exact-boundary ambiguity
-        const float StepY = 0.0002f; // ~0.1 px at 1080p
-        const float CapY = 0.02f;    // stop searching beyond ~10 px
-
-        float minX = float.MaxValue, maxX = float.MinValue;
-        foreach (var v in aperture) { minX = MathF.Min(minX, v.X); maxX = MathF.Max(maxX, v.X); }
-        float span = maxX - minX;
-        if (span <= 0.01f) return (0, 0);
-
-        float worstPlane = 0, atX = 0;
-        const int Samples = 160;
-        for (int s = 0; s <= Samples; s++)
-        {
-            float x = minX + span * (0.01f + 0.98f * s / Samples);
-            if (MathF.Abs(x) > 0.98f) continue; // off screen — no pixel exists there
-            float topY = TopBoundaryY(aperture, x);
-            if (float.IsNaN(topY) || MathF.Abs(topY) > 0.98f) continue; // off screen / no boundary
-
-            var p = new Vector2(x, topY - Inset);
-
-            float planeGap = GapBelow(p, q => AnySliceAdmitsPlanes(slices, q), StepY, CapY);
-
-            if (debug is not null && planeGap > 0.005f)
-                debug.WriteLine(FormattableString.Invariant(
-                    $"    sample x={x:F4} apTop={topY:F4} planeGap={planeGap * fbH / 2f:F2}px"));
-
-            if (planeGap > worstPlane) { worstPlane = planeGap; atX = x; }
-        }
-        // NDC y → pixels at the given framebuffer height.
-        return (worstPlane * fbH / 2f, atX);
-    }
-
-    private static float GapBelow(Vector2 start, Func<Vector2, bool> admitted, float step, float cap)
-    {
-        if (admitted(start)) return 0f;
-        for (float dy = step; dy <= cap; dy += step)
-        {
-            if (admitted(new Vector2(start.X, start.Y - dy)))
-                return dy;
-        }
-        return cap;
-    }
-
-    // Production semantics: each OutsideView polygon is one slice; the union of
-    // slices is drawn. A slice with planes gates per fragment via
-    // gl_ClipDistance (dot((nx,ny,0,d),(x,y,z,1)) >= 0 for an NDC point);
-    // a planeless slice (>8-edge zero-plane fallback, ClipFrameAssembler.cs) admits its whole NDC AABB.
-    private static bool AnySliceAdmitsPlanes(ClipViewSlice[] slices, Vector2 p)
-    {
-        foreach (var slice in slices)
-        {
-            if (slice.Planes.Length == 0)
-            {
-                if (p.X >= slice.NdcAabb.X && p.Y >= slice.NdcAabb.Y
-                    && p.X <= slice.NdcAabb.Z && p.Y <= slice.NdcAabb.W)
-                    return true;
-                continue;
-            }
-            bool inside = true;
-            foreach (var pl in slice.Planes)
-            {
-                if (pl.X * p.X + pl.Y * p.Y + pl.W < 0f) { inside = false; break; }
-            }
-            if (inside) return true;
-        }
-        return false;
-    }
-
-    /// <summary>Highest boundary y of the polygon at vertical line x (NaN when
-    /// the line misses the polygon).</summary>
-    private static float TopBoundaryY(Vector2[] poly, float x)
-    {
-        float best = float.NaN;
-        for (int i = 0; i < poly.Length; i++)
-        {
-            var a = poly[i];
-            var b = poly[(i + 1) % poly.Length];
-            if (MathF.Abs(a.X - b.X) < 1e-9f)
-            {
-                if (MathF.Abs(a.X - x) < 1e-6f)
-                {
-                    float hi = MathF.Max(a.Y, b.Y);
-                    if (float.IsNaN(best) || hi > best) best = hi;
-                }
-                continue;
-            }
-            float t = (x - a.X) / (b.X - a.X);
-            if (t < 0f || t > 1f) continue;
-            float y = a.Y + t * (b.Y - a.Y);
-            if (float.IsNaN(best) || y > best) best = y;
-        }
-        return best;
-    }
-}

tests/AcDream.App.Tests/Rendering/RetailPViewPassExecutorTests.cs

@@ -159,7 +159,9 @@ public sealed class RetailPViewPassExecutorTests
     /// <c>ClearClipRouting</c> + the old <c>DrawLandscapeSliceLate</c> leaf,
     /// one call per active landscape view) is deleted — <c>DrawLandscapeDynamicsPhase</c> now calls
     /// <see cref="RetailPViewPassExecutor.DrawWeatherOnce"/> exactly once,
-    /// unconditionally, with no loop of any kind around it. This
+    /// conditional on <see cref="AcDream.App.Rendering.Walk.WalkFrameDriver.WeatherTurnFired"/>
+    /// (see <see cref="DrawLandscapeDynamicsPhase_GatesDrawWeatherOnceOnWalkDriverWeatherTurnFired"/>
+    /// — the L1 pin), with no loop of any kind around it. This
     /// <c>Assert.Single</c> alone proved insufficient at fix round 1 (K1):
     /// it counts DISTINCT call-site offsets, so it stays green even with a
     /// <c>foreach</c> wrapped around the one call site (the exact round-1
@@ -201,7 +203,14 @@ public sealed class RetailPViewPassExecutorTests
     /// the compiled <c>foreach</c> emits a backward branch (the
     /// condition-check jump back to the loop body) whose span now contains
     /// the call's offset, so this test fails; restore the single
-    /// unconditional call to make it pass again.
+    /// unconditional call to make it pass again. Note for reviewers (added
+    /// at S3 landing hygiene, H4, matching <see cref="DrawWalkSky_RenderSkyCallSiteHasNoEnclosingBackwardBranch"/>'s
+    /// own note): <see cref="CompiledCallGraph.ReadBranches"/> reads only
+    /// <c>br</c>/<c>brtrue</c>/<c>brfalse</c>-family single-target branches —
+    /// it does not decode a compiled <c>switch</c> jump table, but no C# loop
+    /// construct (<c>for</c>/<c>foreach</c>/<c>while</c>/<c>do</c>) ever
+    /// compiles to one, so this pin's blind spot is not a loop shape it
+    /// could miss.
     /// </summary>
     [Fact]
     public void DrawLandscapeDynamicsPhase_DrawWeatherOnceCallSiteHasNoEnclosingBackwardBranch()
@@ -283,6 +292,65 @@ public sealed class RetailPViewPassExecutorTests
                 && branch.TargetOffset > drawOffset);
     }
 
+    /// <summary>
+    /// S3 landing hygiene (H5): strengthens the L1 pin above against a
+    /// conjoined gate the post-hoc three-lens review found it does not
+    /// reject. L1's check (b) only looks at branches STRICTLY BETWEEN the
+    /// <c>WeatherTurnFired</c> getter call and the <c>DrawWeatherOnce</c>
+    /// call — so <c>if (clipAssembly.OutsideViewSlices.Length != 0 &amp;&amp;
+    /// walkDriver.WeatherTurnFired) passes.DrawWeatherOnce(ctx);</c> still
+    /// passes it: the compiler evaluates <c>OutsideViewSlices.Length != 0</c>
+    /// FIRST, so ITS OWN <c>brfalse</c> lands BEFORE the getter call's
+    /// offset — outside L1's window — while <c>calls[c-1]</c> is still the
+    /// getter (the added condition reads <c>OutsideViewSlices</c>, a
+    /// property getter, then <c>.Length</c>, a non-call <c>ldlen</c>, so no
+    /// OTHER call intervenes before the getter). This pin widens the window
+    /// to start at the call immediately before the whole gate —
+    /// <see cref="RetailPViewPassExecutor.DrawUnattachedSceneParticles"/>,
+    /// the outdoor-emitters call the method's own comment names as the last
+    /// call before the gate — and counts EVERY branch in that wider window
+    /// with <c>Assert.Single</c>: production has exactly one, the forward
+    /// <c>brfalse</c>/<c>brfalse.s</c> right after the getter. A conjoined
+    /// gate's extra, earlier condition adds a second branch this wider
+    /// window catches but L1's narrower one cannot.
+    /// MUTATION: change the gate to <c>if
+    /// (clipAssembly.OutsideViewSlices.Length != 0 &amp;&amp;
+    /// walkDriver.WeatherTurnFired)</c> — the branch count in the window
+    /// goes from 1 to 2 and <c>Assert.Single</c> fails (see the commit body
+    /// for the exact recorded failure text).
+    /// </summary>
+    [Fact]
+    public void DrawLandscapeDynamicsPhase_ExactlyOneBranchGuardsDrawWeatherOnce()
+    {
+        MethodInfo method = typeof(RetailPViewRenderer).GetMethod(
+            "DrawLandscapeDynamicsPhase",
+            BindingFlags.Instance | BindingFlags.NonPublic)!;
+        IReadOnlyList<CompiledCall> calls = CompiledCallGraph.Read(method);
+        int particlesIndex = RequiredCallIndex(
+            calls,
+            typeof(RetailPViewPassExecutor),
+            nameof(RetailPViewPassExecutor.DrawUnattachedSceneParticles));
+        int drawIndex = RequiredCallIndex(
+            calls,
+            typeof(RetailPViewPassExecutor),
+            nameof(RetailPViewPassExecutor.DrawWeatherOnce));
+        int particlesOffset = calls[particlesIndex].Offset;
+        int drawOffset = calls[drawIndex].Offset;
+
+        IReadOnlyList<CompiledBranch> branches = CompiledCallGraph.ReadBranches(method);
+        CompiledBranch onlyGuard = Assert.Single(
+            branches,
+            branch => branch.Offset > particlesOffset && branch.Offset < drawOffset);
+
+        Assert.True(
+            onlyGuard.OpCode == OpCodes.Brfalse || onlyGuard.OpCode == OpCodes.Brfalse_S,
+            $"Expected the sole branch between DrawUnattachedSceneParticles and "
+            + $"DrawWeatherOnce to be a brfalse, was {onlyGuard.OpCode}.");
+        Assert.True(
+            onlyGuard.TargetOffset > drawOffset,
+            "Expected the guard branch to skip forward past DrawWeatherOnce.");
+    }
+
     /// <summary>
     /// S3 chunk 4 fix round 2 (L8): the identical loop-shape question K1
     /// asked of <see cref="RetailPViewPassExecutor.DrawWeatherOnce"/>'s call

tests/AcDream.App.Tests/Rendering/TerrainParticleCellVisibilityTests.cs

@@ -3,6 +3,19 @@ using AcDream.App.Rendering;
 
 namespace AcDream.App.Tests.Rendering;
 
+/// <summary>
+/// S3 landing hygiene (H2): <see cref="TerrainModernRenderer.CollectVisibleCells"/>
+/// is frustum-only now — its clip-plane-list and NDC-AABB scissor
+/// parameters and the CPU/GPU clip-region equivalence check they fed had
+/// exactly one production caller (<see cref="TerrainModernRenderer.Draw"/>),
+/// and that caller never actually passed either (grep). The doorway-clip/scissor
+/// rejection cases this file used to pin (<c>RejectsCellsOutsideDoorwayClipPlanes</c>,
+/// <c>RejectsCellsOutsideDoorwayScissorAabb</c>, <c>UnionsCellsFromEveryLandscapeSlice</c>)
+/// pinned a mechanism nothing in production ever fed — deleted with the
+/// parameters. What remains still pins the one thing this method's callers
+/// actually rely on: it publishes the visible terrain cell set per landblock,
+/// respecting an explicit frustum when one is given.
+/// </summary>
 public sealed class TerrainParticleCellVisibilityTests
 {
     [Fact]
@@ -16,9 +29,7 @@ public sealed class TerrainParticleCellVisibilityTests
             Vector3.Zero,
             zMin: 0f,
             zMax: 20f,
-            frustum: null,
+            frustum: null);
-            Matrix4x4.Identity,
-            ReadOnlySpan<Vector4>.Empty);
 
         Assert.Equal(64, cells.Count);
         Assert.Contains(0xA9B40001u, cells);
@@ -40,80 +51,8 @@ public sealed class TerrainParticleCellVisibilityTests
             new Vector3(100f, 100f, 100f),
             zMin: 100f,
             zMax: 120f,
-            frustum,
+            frustum);
-            Matrix4x4.Identity,
-            ReadOnlySpan<Vector4>.Empty);
 
         Assert.Empty(cells);
     }
-
-    [Fact]
-    public void CollectVisibleCells_RejectsCellsOutsideDoorwayClipPlanes()
-    {
-        var cells = new HashSet<uint>();
-        var planes = new[] { new Vector4(-1f, 0f, 0f, -2f) };
-
-        TerrainModernRenderer.CollectVisibleCells(
-            cells,
-            0xA9B4FFFFu,
-            Vector3.Zero,
-            zMin: 0f,
-            zMax: 20f,
-            frustum: null,
-            Matrix4x4.Identity,
-            planes);
-
-        Assert.Empty(cells);
-    }
-
-    [Fact]
-    public void CollectVisibleCells_RejectsCellsOutsideDoorwayScissorAabb()
-    {
-        var cells = new HashSet<uint>();
-
-        TerrainModernRenderer.CollectVisibleCells(
-            cells,
-            0xA9B4FFFFu,
-            Vector3.Zero,
-            zMin: 0f,
-            zMax: 20f,
-            frustum: null,
-            Matrix4x4.Identity,
-            ReadOnlySpan<Vector4>.Empty,
-            ndcClipAabb: new Vector4(-4f, -4f, -2f, -2f));
-
-        Assert.Empty(cells);
-    }
-
-    [Fact]
-    public void CollectVisibleCells_UnionsCellsFromEveryLandscapeSlice()
-    {
-        var cells = new HashSet<uint>();
-
-        TerrainModernRenderer.CollectVisibleCells(
-            cells,
-            0xA9B4FFFFu,
-            Vector3.Zero,
-            zMin: 0f,
-            zMax: 20f,
-            frustum: null,
-            Matrix4x4.Identity,
-            ReadOnlySpan<Vector4>.Empty,
-            ndcClipAabb: new Vector4(1f, -1_000f, 23f, 1_000f));
-        TerrainModernRenderer.CollectVisibleCells(
-            cells,
-            0xA9B4FFFFu,
-            Vector3.Zero,
-            zMin: 0f,
-            zMax: 20f,
-            frustum: null,
-            Matrix4x4.Identity,
-            ReadOnlySpan<Vector4>.Empty,
-            ndcClipAabb: new Vector4(49f, -1_000f, 71f, 1_000f));
-
-        Assert.Equal(16, cells.Count);
-        Assert.Contains(0xA9B40001u, cells);
-        Assert.Contains(0xA9B40011u, cells);
-        Assert.DoesNotContain(0xA9B40009u, cells);
-    }
 }