Replaces the single scope-global distance-sorted RetailAlphaQueue with
retail's own two independent FIFO lists (CLIP/ALPHA, capacity 3000 each,
D3DPolyRender::AddMeshToAlphaList's exact append-only/capacity-drop
behavior — Ghidra-verified 2026-09-04), routed by a new
RetailAlphaMeshRouter porting DrawMesh's five-row immediate/delayed
branch table and ConstructMesh's subset-mask formula as pure functions,
and drained at retail's four normal-world FlushAlphaList sites
(DrawBuilding/DrawBlock/PView::DrawCells/RenderNormalMode) under the
exact Ghidra-verified no-op predicate (both counts strictly below
threshold*3000). A new WalkFrameEventKind.SortCellExit /
IWalkEventSink.OnSortCellExit / IWalkFrameLeafRenderer.FlushSortCellExit
fires once per admitted land-block cell for DrawBlock's 0.75f valve,
pinned by a dedicated far/near ordering test in RetailFrameWalkTests.cs.
WbDrawDispatcher's two submit sites and ParticleRenderer's one route
through the router; since none of the three ever draws during the Sky
leaf, installs a detail surface, or sets MultiPassAlpha, rows 1/2/4/5
are provably unreachable there and the call sites assert loudly rather
than building unexercisable immediate-draw plumbing. FlushFartherThan,
RetailAlphaOrdering.ComputeViewerDistance, and every viewerDistance
argument on the submit path are deleted.
Scope note (packet s4-depth-alpha-packet.md §10): C4 (routing EnvCell's
transparent shell batches through the shared queue) was not attempted —
EnvCell draws one per-cell MultiDrawIndexedIndirect call with no
per-subset deferred-replay abstraction, and building one without visual
verification (no graphical client in this worktree) was judged out of
this bounded chunk's scope. AP-34 is therefore retired and replaced by
two narrower rows rather than deleted outright: AP-236 (the carried-
forward EnvCell-immediate residual) and AP-237 (a newly identified gap:
TranslucencyKind.AlphaBlend can arise from either retail's Alpha/
Translucent bits, mask 0x02/ALPHA, or the Translucent+ClipMap "cloud"
override, mask 0x08/CLIP — GroupKey doesn't retain the raw bit to tell
them apart, so the router always picks ALPHA; only known example is
cloud GfxObj 0x01004C35). Both are compositing-order-only divergences,
never blend/visual ones.
Mutation checks (each applied, confirmed failing, then reverted):
- FIFO drain order reversed -> 5 RetailAlphaQueueTests fail (order).
- FlushAlphaList `<` -> `<=` -> boundary/scratch tests fail (2250 case
reads drained=0 instead of 2250).
- Capacity check loosened (3000 -> 6000) -> overflow-drop test fails
(TryAppend returns true, PendingCount reads 3001).
- IsFirstForList forced true -> flag test fails once inspected on the
pre-flush two-entry snapshot (the post-flush single-survivor version
of this test was vacuous and rewritten).
- Router row 3 condition inverted -> both the hand-traced Theory (6
cases) and the 160-cell independent-truth-table brute force fail (20
mismatches).
- SortCellExit emitted before OnLandscapeCellTurn instead of after ->
RetailFrameWalkTests ordering pin fails ("SCX must immediately follow
its own cell's SC").
- Prepare-per-list instead of prepare-once-combined -> the CLIP/ALPHA
boundary batching test throws (index out of range).
Gates: Release build 0 warnings/0 errors. Hermetic lane (Lane!=Installed
Dat&...&Status!=KnownFailure) 6855/6855 passed. InstalledDat lane 249
passed / 10 failed — exactly the 4 pre-existing failures (#383 x2
LayoutImporter, TowerAscent KnownFailure, #458 Oh_doorway_still
KnownFailure) plus 6 NEW KnownFailure Facts
(AlphaFlushTranscript_*_MatchesRetailFrame2, one per capture) extending
this gate from PM/PC to AM/FL: the flush SITE+THRESHOLD sequence matches
the capture exactly for all six poses (including zero SortCellExit
drains in every capture, confirming the 0.75 valve is inert at these
scene complexities in both retail and this replay); the drained-COUNT-
per-list dimension diverges because this hermetic harness (matching the
existing PM/PC gate's own EmptyAlphaDepthWorldData design) carries no
live GfxObj/particle content, so every observed count reads (0,0)
against retail's real per-frame volume — both sequences quoted in full
per pose in the packet's new §10. Shader classes (VulkanShaderDescriptor
ContractTests/VulkanShaderManifestTests/RenderPackSpirvValidatorTests)
32/32 passed.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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