fix(render): S3 chunk 4 round 2 — draw-gate condition pinned, scissor and terrain-clip stacks deleted, one outside-view slice constructor

Round-1 three-lens FAIL at d60ca4ea0 found: the K2 fix was right in
production but nothing pinned the draw side (restoring the pre-fix gate
left every lane green); a stale "still ends an active scissor" comment
asserted a mechanism the same round had already deleted; the sky.vert
comment claimed retail clips the sky when it draws unclipped; the K6
pin ran through ClipFrameAssembler.Assemble, which has zero production
callers, so it proved nothing about the producer that actually runs.
This round closes L1-L9.

L1 (BLOCKING) — draw-side weather-gate pin. Added
RetailPViewPassExecutorTests.DrawLandscapeDynamicsPhase_GatesDrawWeatherOnceOnWalkDriverWeatherTurnFired:
reads DrawLandscapeDynamicsPhase's compiled call graph and asserts (a)
the call immediately before DrawWeatherOnce is
WalkFrameDriver.get_WeatherTurnFired and (b) exactly one
brfalse/brfalse.s branch sits between that call and the draw, jumping
forward past it. Three mutations, each shown failing:

  M1 (restore `if (clipAssembly.OutsideViewSlices.Length != 0)`):
    Assert.Equal() Failure: Values differ
    Expected: typeof(AcDream.App.Rendering.Walk.WalkFrameDriver)
    Actual:   typeof(AcDream.App.Rendering.ClipFrameAssembly)

  M2 (drop the gate, unconditional call):
    Assert.Equal() Failure: Values differ
    Expected: typeof(AcDream.App.Rendering.Walk.WalkFrameDriver)
    Actual:   typeof(AcDream.App.Rendering.RetailPViewPassExecutor)

  M3 (invert to `if (!walkDriver.WeatherTurnFired)`):
    Assert.Single() Failure: The collection did not contain any matching items
    Expected:   (predicate expression)
    Collection: [CompiledBranch { Offset = 7, OpCode = brfalse.s, TargetOffset = 17 }, CompiledBranch { Offset = 24, OpCode = brtrue.s, TargetOffset = 33 }]

Corrected WalkFrameDriverTranscriptTests.cs's doc comment (the
Collect_WeatherTurnFiredMatchesThePrintedOcLineExactly block): it pins
the print half and the flag only, and now names the real draw-side pin
instead of falsely claiming to double as one.

L2 (MAJOR) — scissor stack deleted, K4 comment corrected. Deleted
IWorldPassSurface.BeginScissor/EndScissor and their RhiWorldPassSurface
bodies, the scissor call inside ClearInteriorDepth, NdcScissorRect.cs +
NdcScissorRectTests.cs (BeginScissor had zero remaining callers, and
RhiWorldPassSurface.BeginScissor was NdcScissorRect.ToPixels' only
production caller). This left RhiWorldPassSurface's 4th constructor
parameter (IRetailPViewFramebufferSource) and RetailPViewPassExecutor.cs's
RetailPViewFramebufferSize/IRetailPViewFramebufferSource/
SilkRetailPViewFramebufferSource types entirely dead (framebuffer size
was needed only for the scissor's NDC-to-pixel conversion) — removed
them and their one call site in FrameRootComposition.cs. Rewrote
RetailPViewPassExecutor.cs's K4 comment: it no longer asserts a live
scissor mechanism; it states that VulkanGpuPassEncoder's constructor
sets the full-attachment scissor once, at pass begin
(VulkanGpuPassEncoder.cs:87), and nothing narrows it after that. KEPT
per the round-1 verdict: ScissorFallbacks, OutsidePlaneCount,
OutsideViewNdcAabb, HasOutsideView, OutdoorVisible, OutdoorSlot,
ClipViewSlice.NdcAabb (the >8-edge zero-plane slice case the punch fans
still consume) and the VulkanViewportMapping.ScissorToVulkan pass-begin
path (IGpuPassEncoder.SetScissor stays). Also deleted
ClipFrameAssembly.TerrainMode/TerrainScissorNdcAabb and their writers
in ClipFrameAssembler.cs (both Assemble and ReassembleOutsideViewFromWalk);
OutsidePlaneCount's formula reduces to `outsideHasScissorFallback ? 0 :
outsideMaxPlaneCount` without needing the deleted TerrainClipMode
comparison (a scissor-fallback slice can only exist when outdoorVisible
is already true, so the three original cases collapse identically).
Deleted the two "terrain=" / "outMode=" diagnostic reads in
WorldRenderDiagnostics.cs (:345, :409) and the now-vestigial
EmitClipRouteProbe "ubo: n=..." segment that read ClipFrame's deleted
terrain bytes.

DEVIATION from L2's literal text: kept the TerrainClipMode enum type
itself — WorldSceneRenderer.cs's flat-world safety path (explicitly
"out of this chunk's scope" per K4's own round-1 comment) still uses it
for an unrelated "did the flat terrain draw" diagnostic flag, with its
own WorldSceneDiagnosticsController/WorldRenderDiagnostics/test
consumers. Deleting the type would require rewriting files outside
every round's declared file list. Reworded its doc comment to state
this plainly.

L3 (MAJOR, completes K3) — dead TerrainClip UBO deleted from the sky
and terrain shaders. Deleted the block, both gl_ClipDistance loops, and
the gl_PerVertex redeclaration (nothing else needs it) from sky.vert,
terrain_modern.vert, terrain_atmospheric.vert. Recompiled via
tools/compile-shaders.ps1 (glslc via the Vulkan SDK, managed shaderc
fallback also runs) — 24/24 pairs compiled; only sky.vert.spv,
terrain_atmospheric.vert.spv and terrain_modern.vert.spv changed.
Re-pinned VulkanShaderManifestTests.cs's frozen retail-oracle hashes
for sky.vert.spv (7d67a9e3624d198b370d402b5c12e4ce925bf9b8e646ef5123636a86d5985ab5)
and terrain_modern.vert.spv (8a73d89ef0e51e550327b9ff8c24857e309103b1d491030cf0d4d8594b45068c)
with dated comments, matching the existing re-pin convention.

Deleted WorldFrameSectionBinding.BindTerrainClip and
WorldFrameSections.TerrainClip (+ its Reset) with its two callers
(SkyRenderer.Rhi.cs:258, TerrainModernRenderer.Rhi.cs:259). DEVIATION
from L3's literal text: kept the shared Zeroed(...) helper in
WorldPassScope.cs — it is also called by BindSceneLighting and
BindClipRegions, both of which stay; deleting it would have broken
those two live bindings. Deleted IWorldPassSurface.BindTerrainClip
(no-op interface method + RhiWorldPassSurface body) and
WorldScenePassExecutor.cs's two calls to it (:121, :235).

Deleted ClipFrame's _terrainBytes field, TerrainBytes/TerrainBytesForTest
properties, Reset's Array.Clear(_terrainBytes), and the stale
header/K3 comment paragraphs. DEVIATION from L3's literal text: kept
ClipFrame.TerrainUboBytes and ClipFrame.TerrainClipUboBinding —
PortalDepthMaskRenderer.Rhi.cs (:140, :187) is a live production
consumer of both constants for the KEPT exit-seal/punch-fan clip block,
which was never in scope for deletion (portal_depth.vert's own
TerrainClip UBO declaration is the KEEP block, untouched). Reworded
both constants' doc comments (ClipFrame.cs, VulkanPipelineLayouts.cs's
UniformTerrainClip) to say only the portal-depth clip block uses
binding 2 now, and corrected the two GpuBindingModel.cs comments that
explained why terrain-tiling/sky-params bindings are 3/4 by naming "the
terrain clip block". Updated VulkanShaderDescriptorContractTests.cs's
TerrainVertexShaderDeclaresItsClipBlockInTheUniformSet (renamed
TerrainVertexShaderDeclaresOnlySceneLightingInTheUniformSet):
terrain_modern.vert's uniform set is now {SceneLighting} only. Deleted
ClipFrameLayoutTests.NoClip_TerrainBytes_Count0_AllZeros and its K3
comment; corrected the class doc comment and LayoutConstants_MatchShaderStruct's
"terrain UBO"/binding-contract comments to describe the portal-depth
consumer instead.

REQUIRED L3 fact (declared-but-never-bound dynamic uniform binding):
VulkanFrameBindings's constructor seeds EVERY declared uniform binding
(0..UniformBindingCount-1, including binding 2) with the shared dummy
buffer's range before any renderer runs (VulkanFrameBindings.cs:128-130,
`_arena.SeedUniform(binding, dummy.Handle.Handle, dummyUniformRange)`
in a loop over every binding) — "Every binding is always bound, whether
a renderer uses it or not... unused ones point at a shared dummy range"
(VulkanFrameBindings.cs:27-31). So after this round, when the sky or
terrain pipeline draws, set 1's shared descriptor layout still declares
binding 2 (portal_depth.vert's own declaration keeps
IsDeclaredUniformBinding(2) true), and its descriptor still points at a
valid (dummy) range from that seed — vkCmdBindDescriptorSets stays
legal even though neither shader statically uses binding 2 any more.
No SPIR-V-side change was needed to keep this legal.

L4 (MAJOR) — one outside-view slice constructor. Extracted
ClipFrameAssembler.AppendOutsideSlice (frame, ViewPolygon,
outsideSlicesList, ref maxPlaneCount, ref hasScissorFallback, ref
scissorFallbacks) — the exact ClipPlaneSet.From/AppendSlot/
ClipViewSlice-construction body — and call it from both Assemble's
outside_view loop and ReassembleOutsideViewFromWalk's outside_view
loop. Rewrote ClipFrameLayoutTests's K6 pin
(ClipViewSlicePlanes_PunchFanPath_EqualsCpuViewPolygonEdgePlanes_ForASyntheticView):
builds a synthetic WalkPortalView from pixel-space points (the
WalkCopyViewTests pattern) via a trivial IWalkRayCaster, runs
BeginWalkFrame(frame, outdoorRoot: false) then
ReassembleOutsideViewFromWalk(assembly, walkView, 640, 480), and reads
assembly.OutsideViewSlices[0].Planes — the exact production pair
RetailPViewPassExecutor.cs's BeginWalkFrame call and
RetailPViewRenderer.cs's ReassembleOutsideViewFromWalk call make.
Mutation (perturbed planes[0].W inside the shared helper, right after
`planes = cps.PlaneArray;`):

  edge 0 midpoint (-0.3,0.10000001) should lie ~on its OWN GPU plane; the closest plane was only 0.5251073 away

The pin's own source contains no `Assemble(` call — grep-checked by
extracting the method body and searching it for the literal text; no
match.

L5 — shader comments corrected. sky.vert/terrain_modern.vert/
terrain_atmospheric.vert now state retail draws the sky once
(LScape::draw @0x00506330 -> GameSky::Draw(sky,0) @0x0050633c, before
draw_check_blocks) and the landscape is view-culled per cell, never
GPU-clipped (RenderDeviceD3D::DrawBlock @0x005a17c0). The "Phase W
Stage 4"/"U.3 default" clip narratives are deleted along with the
blocks they described.

L6 — grep sweep. `grep -rn "<token>" src tests docs/architecture`
returns nothing for SetTerrainClip, BeginDoorwayScissor,
BindTerrainClip, TerrainBytes, "active scissor", and NdcScissorRect —
confirmed after this commit (docs/plans and docs/research keep the
historical record, untouched). TerrainClipMode is the one deliberate
exception (see the L2 deviation note above); every one of its 9
remaining hits is a live, non-stale reference (the enum declaration,
WorldSceneRenderer's flat-path local, or their diagnostic/test
plumbing), not a stale mention of a deleted mechanism.

L7 — Issue130DoorwayStripTests. Deleted AnySliceAdmitsScissor,
worstScissorGapPx and its PIN 1 assertion, the header's scissor
sentences, and the scissorGap half of MeasureTopEdgeGap (dropped the
fbW parameter it alone needed). Rewrote the header: the scissor
mechanism is retired (the sky and landscape draw unclipped; aperture
exactness comes from the depth clear, the exit seals and the interior
repaint). The remaining plane-gap half (the canary PIN,
`worstPlaneGapPx <= 1.2f`) still pins something production reads:
AnySliceAdmitsPlanes walks slice.Planes from the SAME ProjectToClip ->
ClipToRegion -> ClipPlaneSet.From pipeline
RetailPViewPassExecutor.DrawWalkPunchFan reads through
clipAssembly.OutsideViewSlices[activeViewIndex].Planes — so the test
was kept, not deleted.

L8 — DrawWalkSky loop-shape pin. Added
DrawWalkSky_RenderSkyCallSiteHasNoEnclosingBackwardBranch (same
backward-branch-span shape as K1's DrawWeatherOnce pin), plus a note in
both pins that CompiledCallGraph.ReadBranches does not decode a
compiled switch jump table, but no C# loop construct compiles to one.
Mutation (wrapped the RenderSky call in `for (int i = 0; i < 2; i++)`):

  Assert.DoesNotContain() Failure: Filter matched in collection
  Collection: [..., CompiledBranch { Offset = 20, OpCode = brtrue.s, TargetOffset = 25 }, CompiledBranch { Offset = 23, OpCode = br.s, TargetOffset = 66 }, CompiledBranch { Offset = 72, OpCode = blt.s, TargetOffset = 13 }, CompiledBranch { Offset = 80, OpCode = brfalse.s, TargetOffset = 116 }, CompiledBranch { Offset = 88, OpCode = brfalse.s, TargetOffset = 116 }]

(the Offset=72 -> TargetOffset=13 entry is the injected loop's backward
branch spanning the call).

L9 — this message.

Gates: dotnet build 0 warnings / 0 errors. Hermetic filter
(Lane!=InstalledDat&...&Status!=KnownFailure): 6827 passed, 0 failed.
InstalledDat lane against a real DAT directory: 244 passed, 4 failed —
exactly the four known failures (LayoutImporterMediaBearingChildSweepTests
+ LayoutImporterInvisibleSweepTests, both #383; TowerAscentReplayTests,
KnownFailure; WalkTraceConformanceTests.Oh_doorway_still_first_frame_diff,
#458 KnownFailure). No register row added (every deletion here removes
an acdream-only rule; the KEEP items already had their equivalence
pins from round 1). No new flag/probe.

OWED: the lead's ACDREAM_DEVTOOLS=1 four-pose visual self-gate against
the running client is not run by this agent — CLAUDE.md and this
task's own instructions forbid launching the graphical client from
here; that visual/validation-layer pass remains the user's to run
before this round is accepted.

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

src/AcDream.App/Rendering/Shaders/spv/shaders.manifest.json

@@ -311,7 +311,7 @@
       "stages": [
         {
           "stage": "vert",
-          "sourceSha256": "9102b156bd4fd667831353640b2feee2ddde66e88579a4e425566c9b67304b64",
+          "sourceSha256": "51b42232202cd005439e95c50fd325a3849359b3357ab7550af9a4bb404279e4",
           "compiled": true
         },
         {
@@ -327,7 +327,7 @@
       "stages": [
         {
           "stage": "vert",
-          "sourceSha256": "882979f63c858760e977ecafb708416ab01f7adabe4bb38c0630020c087f1c28",
+          "sourceSha256": "42d1dbd0dbd950862e8672f79a3f429f771bae55fd2b5721c3e551a0ea9563b6",
           "compiled": true
         },
         {
@@ -343,7 +343,7 @@
       "stages": [
         {
           "stage": "vert",
-          "sourceSha256": "a3f8592d482793622f7a69c08f8ba828a4e071f2fb5e1763f865be84797bceb7",
+          "sourceSha256": "faf6855222cb2b09da6697c93a93f35cbc57c27bbc124055a6d235c72ef1a23a",
           "compiled": true
         },
         {