BR-1: RESOLVED as already-equivalent - premise falsified by pre-check, equivalence pinned, #113 attribution corrected

The plan's BR-1 ('implement the skipNoTexture draw-time surface gate')
died on its pre-check: acdream ALREADY suppresses every portal fill.
ReplicateProductionEmission_OnPortalFills replicates the exact emission
conditions of the production extractors on the hall/cottage fills:
pos=False neg=False for every one (Stippling.NoPos skips the positive
side at ObjectMeshManager.PrepareGfxObjMeshData:1046,
PrepareCellStructMeshData:1394, CellMesh.Build:44, GfxObjMesh.Build:71;
the fills have no negative surface). There is nothing to gate.

What ships instead: StipplingSurfaceEquivalenceTests - 2,607 polys across
13 building models + 13 environments, ZERO violations both directions:
NoPos <=> untextured-surface. Our build-time skip is proven equivalent to
retail's draw-time skipNoTexture rule (Ghidra 0x0059d4a4, default on
@0x00820e30) on this content. The pin fails loudly if future content
breaks the invariant - the cue to implement the draw-time gate then.

Corrections folded into the plan + comparison docs:
- The #113 phantom residual CANNOT be GfxObj fills (they never reach a
  vertex buffer). Plausible true sites are cell-side: flood-admitted
  cells drawn with the pass-all NoClipSlice when slot-less
  (RetailPViewRenderer.cs:71), and/or cell statics drawn unclipped +
  un-viewcone'd (object-lists-skip-portal-view-gate, confirmed).
  BR-2 opens with the probe that pins which.
- The e46d3d9 user-gate observations (filter removed phantom/doors) were
  confounded - the filter was a provable mesh no-op on shells AND doors.
- Ledger rows solid-surface-skip-missing + the acdream half of
  portal-polys-baked-unconditional re-marked REFUTED-for-fills; the
  retail mechanism descriptions and the un-consumed PortalIndex->
  CBldPortal pairing (BR-4) stand.

Suites: Core 1398 green (1392 baseline + 6 new facts) + the 4 pre-existing
#99-era failures + 1 skip. No production code.

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

docs/plans/2026-06-11-building-render-port-plan.md

@@ -57,28 +57,42 @@ gate) and the client stays playable after every phase. Conformance pins come
 from the dat harness + the flood replay harnesses; retail constants are cited
 inline when ported.
 
-### BR-1 — The draw-time surface gate (kills the phantom class)
+### BR-1 — The surface gate — ✅ RESOLVED AS ALREADY-EQUIVALENT (2026-06-11, execution day 1)
 
-**What:** classify every mesh batch at decode by surface texturedness
-(`Surface.Type & (Base1Image|Base1ClipMap)`); at draw, skip untextured
-batches for **building-shell entities and cell meshes only** (plain objects
-keep drawing them — retail's bypass). Align the cell-side build-time
-`NoPos`/`NoNeg` drop with this rule: run a dat-wide sweep (all CellStructs +
-all building models in the populated landblocks) proving
-`portal-fill ⇔ untextured`; keep the cheaper build-time drop only where the
-sweep proves equivalence, otherwise move to the draw-time gate. GfxObj-side:
-fills stay in the mesh but never draw (matches retail exactly).
+**Premise falsified before implementation (the BR-1 pre-check,
+`ReplicateProductionEmission_OnPortalFills`):** acdream **already suppresses
+every portal fill** — all four extraction paths skip `Stippling.NoPos`
+positive sides (`ObjectMeshManager.PrepareGfxObjMeshData:1046`,
+`PrepareCellStructMeshData:1394`, `CellMesh.Build:44`, `GfxObjMesh.Build:71`),
+and the Holtburg fills have no negative surface. The planned "draw-time
+surface gate" has nothing to gate.
 
-- **Closes:** #113 phantom staircase class (hall ramp, cottage "flying
-  stairs", every building's baked fills) — without touching doors (entities).
-- **Acceptance:** `DumpPortalFillSurfaceTypes`-derived conformance sweep
-  green; hall + hill-cottage phantom gone and doors/windows intact at
-  Holtburg (user gate); all suites green.
-- **Risk note:** apertures whose flood fails become true holes
-  (retail-identical); per-building floods + DrawPortal look-in already cover
-  the visible cases. If a hole shows at an unflooded aperture, that is BR-2/
-  BR-4 evidence, not a BR-1 regression.
-- **Size:** ~2 commits (batch metadata plumb + draw gate; sweep test).
+**What shipped instead — the equivalence pin**
+(`StipplingSurfaceEquivalenceTests`): 2,607 polys across 13 building models +
+13 environments, **zero violations both directions** — `NoPos ⇔ untextured
+surface`. Our build-time skip is therefore *proven equivalent* to retail's
+draw-time `skipNoTexture` rule on this content; the
+`portal-poly-suppression-criterion` divergence closes as
+equivalent-with-proof. The pin fails loudly if future content breaks the
+invariant (the cue to implement the draw-time gate then).
+
+**Consequences (the honest part):**
+- The **#113 phantom residual is NOT GfxObj fills** — it cannot be, they
+  never reach a vertex buffer. The "root cause #2" attribution from the
+  e46d3d9 session is corrected; the e46d3d9 user-gate observations (filter
+  removed phantom/doors) were confounded — the filter was a provable mesh
+  no-op on both shells and door parts.
+- The phantom's plausible true sites are cell-side: flood-admitted stair
+  CELLS drawn with a pass-all slice when the assembler hands them no slot
+  (`RetailPViewRenderer.cs:71` draws ALL visible cells; `NoClipSlice`
+  default), and/or stair-cell STATICS drawn unclipped + un-viewcone'd by
+  design (`object-lists-skip-portal-view-gate`, confirmed). **BR-2's first
+  task is a 10-minute probe at the hall bisect spot pinning which** —
+  the closure moves to BR-2/BR-3 (shells) and BR-5 (statics).
+- **Closes:** the `portal-poly-suppression-criterion` divergence (as
+  proven-equivalent); #113's closure moves to BR-2/BR-3/BR-5.
+- **Shipped:** the pre-check + equivalence pin tests; no production code
+  (none needed).
 
 ### BR-2 — Aperture depth machinery (punch / seal / clear)
 
@@ -96,12 +110,20 @@ interior stage, gated on whether any seal was drawn (`portalsDrawnCount`);
 mesh (retail `DrawBuilding` order) so the shell's depth closes everything
 outside the punch.
 
+- **First task (from BR-1's falsification):** the 10-minute probe at the
+  hall bisect spot — when the phantom is visible, log per stair cell
+  (0x100..0x106) whether it drew with a real clip slot or the pass-all
+  `NoClipSlice`, and whether its statics drew — pinning the phantom's true
+  draw site (shells → fixed here/BR-3; statics → BR-5).
 - **Closes:** #108 (outdoor terrain sweeping across the upstairs door — the
   missing true-depth seal is the confirmed `missing-portal-depth-fence`
-  divergence); the outdoor-root depth-discipline gap; part of #109.
+  divergence); the outdoor-root depth-discipline gap; part of #109; the
+  #113 phantom residual if the probe pins it on pass-all shell slices.
 - **Acceptance:** cellar↔main-floor walk shows no grass sweep (user gate);
-  new harness fact: seal depth = portal plane depth inside the clipped
-  aperture polygon (GL readback test or probe assertion); suites green.
+  phantom-spot check at the hall (user gate, replaces the old BR-1
+  acceptance); new harness fact: seal depth = portal plane depth inside the
+  clipped aperture polygon (GL readback test or probe assertion); suites
+  green.
 - **Size:** ~3 commits (~80 lines of GL + clipper reuse per the area
   estimate, plus the clear re-shape and order swap).
 
@@ -285,11 +307,15 @@ issue, none blocks BR-1…BR-8.
 ## 5. Sequencing summary
 
 ```
-BR-1 (surface gate)          — first; standalone visual win, lowest risk
-BR-2 (depth punch/seal)      — second; enables BR-3
+BR-1 (surface gate)          — ✅ RESOLVED as already-equivalent (pin shipped,
+                               no production code; #113 closure moved to
+                               BR-2/3/5 — see BR-1 section)
+BR-2 (depth punch/seal)      — FIRST implementation phase; opens with the
+                               phantom-site probe; enables BR-3
 BR-3 (delete shell chop)     — closes #114 with BR-2
 BR-4 (draw-driven floods)    — closes #109; flood fidelity
-BR-5 (viewconeCheck)         — particles/objects through the same gate
+BR-5 (viewconeCheck)         — particles/objects through the same gate;
+                               closes the phantom if it is statics-side
 BR-6 (one gate + deletions)  — consolidation after the discipline is in
 BR-7 (collision A6.P4)       — independent track; may interleave with BR-2..5
 BR-8 (camera/lighting/LOD)   — feel tier; BR-8a may land early