fix #130 (the real strip): drawn-shell lift vs draw-space portal consumers

The user's re-gate refuted the scissor fix as THE strip (6c4b6d6 was a
real but sub-pixel under-coverage): the strip survived, screenshot at a
doorway, full width of the opening, top edge only, "very subtle".

Root cause (pinned by Issue130DoorwayStripTests.UnliftedGate_*): the
+0.02 m shell render lift. Cell shells DRAW 2 cm above the dat origin
(z-fight vs coplanar terrain); f35cb8b (the #119-residual fix,
2026-06-11) deliberately reverted the VISIBILITY graph to the physics
(unlifted) transform - but the OutsideView color gate (terrain/sky/
scissor through the doorway) and the seal/punch depth fans are
DRAW-space consumers and kept projecting the unlifted polygons. The
drawn lintel therefore sits one lift-projection above the gate's top
edge - measured 6.7 px at a 2.4 m doorway - and that band never
receives terrain/sky color while the seal also stamps 2 cm low.
A regression from f35cb8b, NOT from the W=0 clip port (987313a stays
exonerated). Vertical aperture edges are immune (the lift slides them
along themselves) - top edge only, exactly as reported; explains the
"also NOW" timing precisely.

Fix - draw space draws lifted, visibility stays physics (the f35cb8b
invariant, now symmetric):
- PortalVisibilityBuilder.Build gains drawLiftZ: the exit-portal branch
  projects the OutsideView region with the lifted transform; flood
  admission, side tests, and CellViews are untouched (default 0 keeps
  every existing visibility test bit-identical).
- The seal/punch fans (DrawRetailPViewPortalDepthWrite) lift their
  world verts to the drawn shell's space.
- One shared constant PortalVisibilityBuilder.ShellDrawLiftZ feeds the
  shell registration (GameWindow:5604), the gate, and the fans.

Register: AP-32 ADDED - the +0.02 lift had NO row (a pre-register
deviation the 2026-06-12 sweep missed). The row records the split
invariant both ways: a draw-space consumer that forgets the lift
re-opens the #130 strip; a visibility consumer that picks the lifted
transform re-opens the #119-residual side-cull.

Pins: the lifted gate covers the drawn (lifted) aperture to 0.00 px
across the 147-combo sweep; the unlifted gate shows the 6.7 px strip
(sensitivity proof - if the lift is ever removed, this test says the
drawLiftZ plumbing can go too).

Suites: App 257+1skip / Core 1439+2skip / UI 420 / Net 294 green.
Awaiting the user re-gate at a doorway with the lintel on screen.

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

docs/ISSUES.md

@@ -4514,45 +4514,50 @@ cap constant (0.5 m) is the tuning knob — see AD-18.
 
 ## #130 — Background-color strip along the TOP outer edge of a doorway when looking out from inside
 
-**Status:** FIX SHIPPED — awaiting user visual gate
+**Status:** FIX 2 SHIPPED — awaiting user visual re-gate
 **Severity:** LOW-MEDIUM (small strip, but on the most-stared-at pixels in the game)
 **Filed:** 2026-06-12 (user report, post-#119-close session)
-**Component:** render — doorway-slice scissor box math (AD-17 family)
+**Component:** render — drawn-shell lift vs draw-space portal consumers (AP-32)
 
 **Symptom (user):** standing inside looking out through a doorway, a
 thin strip of background (clear/world) color runs along the OUTER edge
-of the TOP of the doorway opening.
+of the TOP of the doorway opening. Survived the scissor fix (`6c4b6d6`)
+— user screenshot 2026-06-12 evening, "very subtle".
 
-**Root cause (pinned headlessly 2026-06-12, `Issue130DoorwayStripTests`
-— 147 eye/gaze combos at the real A9B4 0x0170 exit door):** the
-`BeginDoorwayScissor` NDC→pixel conversion (`Floor(origin) +
-Ceiling(size)`) put the box's far edge at `floor(min)+ceil(max−min)` —
-up to ONE PIXEL SHORT of the true top/right edge at unlucky fractional
-alignments. The scissor brackets the ENTIRE landscape slice (sky,
-terrain, statics, weather), the seal stamps the full aperture at true
-depth, and the shell ends at the aperture edge — so the cut pixel row
-never receives color: a background strip along the top edge that comes
-and goes as the eye moves (alignment shifts). Captured live by the
-harness: top edge y=0.7938 at 1080p → row 968 cut; right edge column
-1296 cut at 1920. This violated AD-17's own doctrine (over-inclusion
-safe, under-inclusion is the bug class).
+**Root cause (the REAL strip, pinned by
+`Issue130DoorwayStripTests.UnliftedGate_LeavesTheStripAtTheDrawnTopEdge`):
+the +0.02 m shell render lift.** Cell shells DRAW 2 cm above the dat
+origin (z-fight vs terrain, AP-32); since `f35cb8b` (the #119-residual
+fix) the visibility graph deliberately uses the PHYSICS (unlifted)
+transform — but the OutsideView color gate and the seal fans, which are
+DRAW-space consumers, kept the unlifted polygons. The drawn lintel
+therefore sits one lift-projection ABOVE the gate's top edge —
+**6.7 px at a 2.4 m doorway** (measured) — and that band gets no
+terrain/sky color while the seal also stamps 2 cm low. Regression from
+`f35cb8b` (2026-06-11), NOT from the W=0 clip port. Vertical edges are
+immune (the lift slides them along themselves) — top edge only, exactly
+as reported.
 
-**Lead 1 REFUTED:** the W=0 clip port `987313a` is exonerated by the
-same harness — the CPU polygon pipeline (ProjectToClip → ClipToRegion
-merges → ClipPlaneSet planes) is sub-pixel exact against the raw
-aperture projection (worst 0.54 px; 0.00 px in the aligned case). For
-an all-in-front doorway polygon the port is bit-identical to the old
-path by construction (the W clip pass only runs when a vertex has
-w < 0).
+**Fix 2:** draw-space consumers re-apply the lift —
+`PortalVisibilityBuilder.Build(drawLiftZ:)` projects the exit-portal
+OutsideView region with the lifted transform (flood admission, side
+tests, CellViews stay physics-space per f35cb8b), and the seal/punch
+fans lift their world verts. One shared constant
+`PortalVisibilityBuilder.ShellDrawLiftZ` now feeds the shell
+registration, the gate, and the fans. AP-32 register row added (the
+lift had no row). Pins: the lifted gate covers the drawn aperture to
+0.00 px across the 147-combo sweep; the unlifted gate shows the 6.7 px
+strip (sensitivity).
 
-**Fix:** conservative outer bound `floor(min)/ceil(max)` extracted to
-`NdcScissorRect.ToPixels` (GL-free, unit-tested); `BeginDoorwayScissor`
-delegates. Pins: `NdcScissorRectTests` (containment property + both
-captured alignments) + `Issue130DoorwayStripTests` (scissor never cuts
-plane-admitted fragments; CPU-pipeline exactness canary ≤1.2 px).
+**Fix 1 (also real, sub-pixel): `6c4b6d6`** — the doorway-slice scissor
+`Floor(origin)+Ceiling(size)` cut up to 1 px off the top/right edges;
+now a conservative outer bound (`NdcScissorRect`, AD-17 doctrine).
+The W=0 clip port `987313a` is exonerated (CPU pipeline sub-pixel exact
+in like-for-like space).
 
-**Gate:** stand inside any cottage, look out the door, sweep the gaze —
-no background strip at the top edge at any alignment.
+**Gate:** stand inside, look out the door with the lintel on screen,
+sweep the gaze — no background strip at the top edge at any alignment
+or distance.
 
 ---
 

docs/architecture/retail-divergence-register.md

@@ -92,7 +92,7 @@ accepted-divergence entries (#96, #49, #50).
 
 ---
 
-## 3. Documented approximation (AP) — 31 rows
+## 3. Documented approximation (AP) — 32 rows
 
 | # | Divergence | Where (file:line) | Why it is safe / justified | Risk if assumption breaks | Retail oracle |
 |---|---|---|---|---|---|
@@ -127,6 +127,7 @@ accepted-divergence entries (#96, #49, #50).
 | AP-29 | Target-indicator fallback for entities with no baked selection sphere: invented 1.5 m × scale box + 16/12 px screen floors (primary path is a faithful `GetObjectBoundingBox` port) | `src/AcDream.App/UI/TargetIndicatorPanel.cs:86` | Fallback only fires when the Setup didn't bake a selection sphere — rare in practice | Sphere-less entities get a non-retail indicator size/placement; the pixel floors prevent retail's far-distance collapse | `SmartBox::GetObjectBoundingBox` 0x00452e20; `GetSelectionSphere` |
 | AP-30 | AutonomousPosition diff cadence compares with epsilons (1 mm pos, 1e-4 normal, 1 mm dist); retail's `Frame::is_equal` is an exact float compare | `src/AcDream.App/Input/PlayerMovementController.cs:1541` | Sub-millimeter epsilon is well below any movement worth suppressing; comparisons are against last-SENT state so drift accumulates past the epsilon | Sub-epsilon drift suppresses an AP send retail would have made — negligible today; a consumer expecting retail's exact send-on-any-change cadence sees fewer packets | `Frame::is_equal` pc:700263 |
 | AP-31 | Scenery placement drift + the 0xA9B1 road-edge tree — WB-upstream divergences from retail, ACCEPTED (**#49/#50**, 2026-05-11) | `src/AcDream.Core/World/SceneryGenerator.cs` (via `WbSceneryAdapter`) | Piecemeal patching against WB upstream is net-negative (the `e279c46` road-check attempt over-suppressed scenery elsewhere, reverted `677a726`); visible impact = a handful of trees a few meters off | The same WB-upstream class could hide a *larger* placement divergence elsewhere; revisit only via a coherent ACME-style per-vertex filter port | `CLandBlock::get_land_scenes`; ACME GameScene.cs:1074 per-vertex road filter |
+| AP-32 | Cell shells DRAW +0.02 m above the dat EnvCell origin (`ShellDrawLiftZ`, z-fight vs coplanar terrain); retail draws at the origin verbatim. Split invariant: PHYSICS + visibility graph UNLIFTED (f35cb8b, **#119**-residual), every DRAW-space consumer of portal/cell geometry LIFTED (OutsideView color gate via `Build(drawLiftZ)`, seal/punch fans — **#130**) | `src/AcDream.App/Rendering/GameWindow.cs:5604` (const at `PortalVisibilityBuilder.ShellDrawLiftZ`) | Shell floors coplanar with terrain z-fight in our z-buffered frame; the 2 cm lift is the documented stand-in | A new draw-space consumer of portal/cell polygons that forgets the lift re-opens a 2 cm seam at horizontal aperture edges (the #130 top-edge strip, ~7 px at 2.4 m); a visibility consumer that picks up the LIFTED transform re-opens the #119-residual horizontal-portal side-cull | retail draws cell geometry at the dat EnvCell origin (no lift) |
 
 ---