diff --git a/docs/ISSUES.md b/docs/ISSUES.md
index 231bef55..bf4cfaa5 100644
--- a/docs/ISSUES.md
+++ b/docs/ISSUES.md
@@ -106,23 +106,34 @@ corridor, and (c) pops into existence on entering the room. Classic
portal-visibility miss: the stair geometry's cell is not reached by the
portal flood from the viewer's cell until the viewer crosses into it.
-**Status update:** π‘ FIX SHIPPED 2026-07-06 β pending user gate.
-**Root cause (found via the probe launch):** the geometry never vanished β
-its LIGHTS did. `BuildPointLightSnapshot` kept only the `MaxGlobalLights=128`
-point lights nearest THE CAMERA; the Facility Hub registers 366 fixtures, so
-238 were evicted per frame by camera distance. A room whose torches all
-ranked past the cap rendered at bare 0.2 ambient (near-black in a dungeon =
-"not visible"); approaching re-admitted them ("pops into existence"); the
-eviction boundary sweeping with the camera dropped the ramp's lights
-mid-descent ("disappears on the last step"). Retail's
-`minimize_object_lighting` (0x0054d480) has no global camera-nearest cap.
-**FIX:** cap raised to a non-biting 1024 safety valve (register row AP-85);
-pin `LightManagerTests.PointSnapshot_HubScaleLightCount_ObjectSelectionIsCameraInvariant`
-(RED at 128, GREEN at 1024). Investigation ledger (12 refuted mechanisms +
-the probe run that discriminated):
+**Status:** OPEN β root cause CONFIRMED; fix DEFERRED to the A7
+dungeon-lighting arc (the cap-raise fix was live-tested and REVERTED,
+see below).
+**Root cause (confirmed via the probe launches):** the geometry never
+vanishes β its LIGHTS do. `BuildPointLightSnapshot` keeps only the
+`MaxGlobalLights=128` point lights nearest THE CAMERA; the Facility Hub
+registers 366 fixtures, so 238 are evicted per frame by camera distance.
+A room whose torches all rank past the cap renders at bare 0.2 ambient
+(near-black in a dungeon = "not visible"); approaching re-admits them
+("pops into existence"); the eviction boundary sweeping with the camera
+drops the ramp's lights mid-descent ("disappears on the last step").
+Retail's `minimize_object_lighting` (0x0054d480) has no global
+camera-nearest cap.
+**Why the fix is deferred:** raising the cap to 1024 (commit `4d25e04d`)
+made the pops stop but exposed three unported retail lighting semantics
+that DOMINATE the frame with the full pool active: (a) lights reach
+through solid floors/walls β retail registers lights per-CELL
+(`insert_light` 0x0054d1b0) so the under-room portal light never touches
+the corridor above; our flat sphere-overlap has no reach notion; (b)
+stationary weenie fixtures ride the DYNAMIC 1/d falloff (~9Γ retail's
+static 1/dΒ³ at 3 m β the #143 isDynamic misassignment for ACE-served
+fixtures); (c) an unexplained striped z-fight-like artifact on lit floor
+regions (user screenshot). Reverted to 128 (`AP-85` documents the
+stopgap; the desired-end-state pin is Skip'd in LightManagerTests).
+**A7 fix shape:** per-cell light registration (insert_light port) +
+static curve for stationary fixtures + the stripe hunt, THEN uncap.
+Full investigation ledger:
`docs/research/2026-07-06-176-177-render-pair-investigation.md`.
-**Gate:** stairs/stair room stay visible (lit) from the corridor, through
-the descent, at all approach angles.
**Acceptance:** the staircase renders whenever its room is visible through
the connecting opening, and stays rendered through the full descent.
@@ -143,25 +154,28 @@ render; the physics fix landed (seam shake gone, user-gated) and the flash
REMAINS β so it is a render-side issue in its own right, correlated with
camera angle.
-**Status update:** π‘ FIX SHIPPED 2026-07-06 β pending user gate.
-**Root cause (found via the probe launch):** per-cell LIGHTING pops, not a
-draw failure. The probe run reproduced the flash while the ambient branch
-([light] insideCell/0.2 grey β stable) and the portal flood ([pv-input] β
-zero drops in 54k frames) were provably healthy β which eliminated the
-last CPU-side theories and exposed the one channel the probes could not
-see: per-cell 8-light SET COMPOSITION. `BuildPointLightSnapshot` kept the
-128 lights nearest THE CAMERA of the Hub's 366 registered fixtures; an
-in-range torch of a visible cell that ranked past the cap was evicted, so
-that CELL's Gouraud lighting flipped as the camera moved β discontinuity
-lines at exactly cell-seam granularity, camera-angle dependent (the chase
-boom swings the camera position, re-ranking the 128), and a torch-losing
-floor drops to dim blue-grey stone (the perceived purple flash). Twelve
-other mechanisms refuted first β ledger in
+**Status:** OPEN β root cause CONFIRMED; fix DEFERRED to the A7
+dungeon-lighting arc (see #177 for the revert story β same mechanism,
+same deferral).
+**Root cause (confirmed via the probe launches):** per-cell LIGHTING pops,
+not a draw failure. The probe run reproduced the flash while the ambient
+branch ([light] β stable 0.2 grey) and the portal flood ([pv-input] β
+zero drops in 54k frames) were provably healthy, which eliminated the
+last CPU-side theories and left the one channel the probes cannot see:
+per-cell 8-light SET COMPOSITION. The camera-capped snapshot (128 of the
+Hub's 366 fixtures, nearest-to-camera) evicts in-range lights of visible
+cells; the flipping unit is a CELL, so the discontinuities sit at exactly
+cell-seam granularity, swing with the camera position (the chase boom),
+and the dominant flipping light is the under-room PORTALS' purple β
+hence purple flashes on the floor. Twelve other mechanisms were refuted
+first β ledger in
`docs/research/2026-07-06-176-177-render-pair-investigation.md`.
-**FIX:** `MaxGlobalLights` 128 β 1024 non-biting safety valve (AP-85);
-pin `LightManagerTests.PointSnapshot_HubScaleLightCount_ObjectSelectionIsCameraInvariant`.
-**Gate:** no purple/lighting flashes on floors at corridor seams from any
-camera angle while running the 015Eβ017A loop.
+**Deferral:** the uncapped pool (live-tested `4d25e04d`, reverted)
+stabilizes the pops but floods rooms with through-floor portal light
+(no per-cell reach semantics), over-strong dynamic-curve fixture light,
+and a striped floor artifact β the A7 arc owns the real fix (per-cell
+`insert_light` registration + static fixture curve + stripe hunt, then
+uncap). Register row AP-85.
**Acceptance:** no purple/placeholder flashes on dungeon floors from any
camera angle at the corridor seams.
diff --git a/docs/architecture/retail-divergence-register.md b/docs/architecture/retail-divergence-register.md
index 4766abe6..baeab278 100644
--- a/docs/architecture/retail-divergence-register.md
+++ b/docs/architecture/retail-divergence-register.md
@@ -179,7 +179,7 @@ accepted-divergence entries (#96, #49, #50).
| AP-80 | **PlanFromVelocity survives for velocity-only NPC cycles** (M16): UpdatePosition-derived speed picks Ready/Walk/Run cycles for server-controlled creatures whose UMs never arrive (scripted-path NPCs); retail derives every cycle from motion messages through the motion tables (R4-V4 note; pre-existing mechanism, row added per the V4 plan) | `src/AcDream.Core/Physics/ServerControlledLocomotion.cs` (`PlanFromVelocity`); consumer `GameWindow.ApplyServerControlledVelocityCycle` | Some ACE entities move by position updates alone β without this, they slide in T-pose; constants (StopSpeed 0.2, RunThreshold 1.25) tuned against live ACE traffic | Cycle-pick thresholds are acdream inventions β a creature intended to walk fast may show run legs near the threshold | retire in R6 (root motion + full per-tick order) |
| AP-81 | **Remote-DR gravity toggled via the Gravity STATE bit**: the jump handler sets `Body.State \|= Gravity` at VectorUpdate and both landing blocks clear it after `HitGround()`; retail keeps GRAVITY set for the object's whole life and gates gravity ACCELERATION on the Contact transient (`calc_acceleration`) (pre-existing K-fix9/K-fix15 mechanism, row added during #161 β which also fixed the ordering so `Motion.HitGround()`'s verbatim `state&0x400` gate runs BEFORE the clear) | `src/AcDream.App/Rendering/GameWindow.cs` (VectorUpdate jump handler + the two landing blocks) | The DR tick integrates gravity only for airborne remotes; the flag dance delivers exactly that without porting the full contact-gated `calc_acceleration` chain; the #161 ordering fix keeps the retail HitGround contract satisfied | Any NEW call into `Motion.HitGround`/`LeaveGround` placed after the clear silently no-ops on the gravity gate (the #161 leg-2 class); grounded remotes carry a non-retail state word (probes comparing state bits vs retail mislead) | `CPhysicsObj::calc_acceleration` (contact-gated); `set_on_walkable` 0x00511310; retire in R6 (contact-gated accel + persistent GRAVITY) |
| AP-82 | **StickyManager deep-overlap back-off sign pin**: when the stick-gap overlap exceeds one tick's step (`speedΓquantum < \|dist\|`, `dist < 0`), acdream applies `delta = β(speedΓquantum)` (rate-limited back-off); ACE's literal port keeps `+delta` there β a runaway that steers INTO the target with equilibrium at centers-coincident. The BN mush (0x00555554-0x00555597) is unreadable on exactly this compare; the pin is refuted-by-evidence against ACE-literal: #171 gate-3 probe showed 1661 deep-overlap ticks all steering inward (monsters converged to centerDistβ0 β "monster inside the player") while retail side-by-side on the same ACE shows separation. ACE servers essentially never reach the branch (quantum β₯1/30 β threshold ~1 m; render-rate quanta β ~0.13 m) | `src/AcDream.Core/Physics/Motion/StickyManager.cs` (`AdjustOffset` delta clamp; conformance `StickyManagerTests.AdjustOffset_DeepOverlap_BacksOff_RateLimited`) | Minimal interpretation consistent with the mush structure AND observed retail; identical to ACE-literal in every shallow/outside case | If retail's true deep-overlap behavior differs (e.g. no movement at all), our back-off rate diverges in that rare state; verify via cdb `StickyManager::adjust_offset` trace with a forced overlap when convenient | `StickyManager::adjust_offset` 0x00555430 (x87 mush); ACE StickyManager.cs:117-121 (the literal branch this pin overrides) |
-| AP-85 | **Per-frame flat point-light snapshot with a 1024 nearest-to-camera safety cap** (#176/#177 fix, 2026-07-06): acdream collects ALL lit point/spot lights into one flat per-frame snapshot (`BuildPointLightSnapshot`) that per-cell/per-object selection (`SelectForObject`, the faithful AP-16 8-cap) draws from; retail registers lights per-CELL (`insert_light` 0x0054d1b0) and consults the reaching set with NO global pool cap. The previous cap of 128 BIT in the Facility Hub (366 registered fixtures β 238 camera-distance evictions/frame β in-range torches of VISIBLE cells dropped from their 8-sets β per-cell Gouraud lighting popped with camera movement = the #176 purple seam flash + the #177 stair-room light pop-in) | `src/AcDream.Core/Lighting/LightManager.cs` (`MaxGlobalLights`, `BuildPointLightSnapshot`); pin `LightManagerTests.PointSnapshot_HubScaleLightCount_ObjectSelectionIsCameraInvariant` | The flat scan is a perf-shape adaptation (feel-identical while the cap never bites); per-object selection stays retail's `minimize_object_lighting` 8-nearest | If content ever registers >1024 lit lights in relevance range, per-cell sets silently become camera-dependent again β the #176/#177 pop class returns. Raise the cap, don't tune it | `minimize_object_lighting` 0x0054d480 (no global pool cap); `insert_light` 0x0054d1b0 (per-cell registration) |
+| AP-85 | **Per-frame flat point-light snapshot capped at the 128 lights nearest THE CAMERA** (`BuildPointLightSnapshot`); retail registers lights per-CELL (`insert_light` 0x0054d1b0) and `minimize_object_lighting` (0x0054d480) consults the reaching set with NO global pool cap. The cap BITES in the Facility Hub (366 registered fixtures β 238 evictions/frame) and the eviction is the CONFIRMED mechanism of #176 (purple seam flash β an in-range torch of a visible cell ranks past the cap and drops from that cell's 8-set; per-cell Gouraud pops as the camera moves) + #177 (a stair room's fixtures all past the cap render it 0.2-ambient-dark until approach). β οΈ Raising to 1024 was live-tested 2026-07-06 and REVERTED: the uncapped pool exposes (a) light-through-solid-floors (no per-cell reach/occlusion β the under-room portal light washes the corridor above), (b) stationary weenie fixtures on the DYNAMIC 1/d falloff (~9Γ retail's static 1/dΒ³ at 3 m; #143 misassignment for ACE-served fixtures), (c) an unexplained striped floor artifact. Fix = the A7 arc: per-cell light registration + static curve for fixtures + the stripe hunt, THEN uncap | `src/AcDream.Core/Lighting/LightManager.cs` (`MaxGlobalLights` β the load-bearing-stopgap comment); desired-end-state pin (Skip) `LightManagerTests.PointSnapshot_HubScaleLightCount_ObjectSelectionIsCameraInvariant` | The 128 cap keeps the light pool local to the camera, which accidentally APPROXIMATES per-cell reach (far lights can't leak through floors into view) β the least-wrong state until A7 ports real per-cell registration | The #176/#177 pop class stays live until A7 (purple flashes at seams; unlit rooms popping lit on approach); any dungeon with >128 fixtures has camera-dependent per-cell lighting | `minimize_object_lighting` 0x0054d480 (no global pool cap); `insert_light` 0x0054d1b0 (per-cell registration); `calc_point_light` 0x0059c8b0 (static 1/dΒ³ bake curve) |
| AP-84 | **BSP shadow-shape part poses = motion-table default-state frame snapshot at registration, not retail's live CPhysicsPart pose** (#175): server entities with a wire MotionTableId register their BSP part shapes at the default style's first-cycle LowFrame pose (the closed pose for doors β `GameWindow.MotionTableDefaultPose`); retail collision reads each part's CURRENT pose every test. Equivalent for the door lifecycle (closed = default pose; open = ETHEREAL bypasses collision entirely, #150) and for idle statics | `src/AcDream.App/Rendering/GameWindow.cs` (`MotionTableDefaultPose` + the RegisterServerEntityCollision override); `src/AcDream.Core/Physics/ShadowShapeBuilder.cs` (`partPoseOverride`) | Registration is one-shot in acdream (retail re-poses parts per frame); the default-state pose is the correct idle pose and the only non-ethereal pose doors ever collide in | An entity whose server-driven motion state materially MOVES a BSP-bearing part while NON-ethereal would collide at the stale default pose (no known case β doors are the dominant BSP-part weenies); revisit if animated non-ethereal BSP movers appear | `CPhysicsPart` live pose (see #150 notes); motion-table default state = CPartArray init; ShadowShapeBuilder placement-frame fallback for table-less entities |
| AP-83 | **CylCollideWithPoint PerfectClip TOI sub-branches decoded via ACE, not the binary**: the CCylSphere family port (2026-07-05, retires AP-6) reads `collide_with_point`'s PerfectClip time-of-impact math (0x0053adb6+) from ACE `CylSphere.CollideWithPoint` because the BN x87 mush is unreadable there; two ACE-verbatim quirks ported as-is (`movement.Z + radius` in the not-definite ascending case; `GlobalCurrCenter[0]` used even for head-sphere hits β the latter matches the raw decomp read). NOT exercised in M1.5: no mover sets PerfectClip (players never do; the non-PerfectClip path β SetCollisionNormal + Collided β is decomp-verified). Separately, the grounded head-sphere slide passes the HEAD disp per retail 0x0053b843 where ACE passes the foot disp β retail wins (ACE bug, not copied) | `src/AcDream.Core/Physics/TransitionTypes.cs` (`CylCollideWithPoint`; pseudocode doc `docs/research/2026-07-05-ccylsphere-collision-family-pseudocode.md` Β§7-8) | The load-bearing paths (non-PerfectClip Collided; the family's step-up/step-down/land) are decomp-verified; the TOI tail is dead code until missiles arm PerfectClip | If missiles (F.3) arm PerfectClip, the two ACE quirks may diverge from retail β clip-through or wrong deflection on cylinder targets; re-decompile 0x0053acb0 in Ghidra before shipping missiles | `CCylSphere::collide_with_point` 0x0053acb0 (pc:324173, x87 mush from 0x0053adb6); ACE CylSphere.cs `CollideWithPoint` |
diff --git a/src/AcDream.Core/Lighting/LightManager.cs b/src/AcDream.Core/Lighting/LightManager.cs
index 570669de..3ba78d16 100644
--- a/src/AcDream.Core/Lighting/LightManager.cs
+++ b/src/AcDream.Core/Lighting/LightManager.cs
@@ -176,18 +176,28 @@ public sealed class LightManager
public const int MaxLightsPerObject = 8;
/// Hard cap on the per-frame global point-light snapshot the shader
- /// indexes. #176/#177 (2026-07-06): the old value of 128 BIT in the Facility
- /// Hub β 366 registered fixtures, so 238 were evicted per frame by camera
- /// distance. An in-range torch of a VISIBLE cell that ranked past the cap
- /// dropped out of the cell's 8-light set, so per-cell Gouraud lighting popped
- /// as the camera moved (the purple seam flash / the stair-room pop-in).
- /// Retail's minimize_object_lighting (0x0054d480) has NO global
- /// camera-nearest cap β every registered light reaching an object is a
- /// candidate. 1024 is a pure safety valve (the whole Facility Hub registers
- /// 366; GlobalLightPacker grows to fit, 64 B/light on the GPU) and must never
- /// bite at real content scale β if it ever does, raise it, don't tune it.
- /// Pin: LightManagerTests.PointSnapshot_HubScaleLightCount_ObjectSelectionIsCameraInvariant.
- public const int MaxGlobalLights = 1024;
+ /// indexes. β οΈ LOAD-BEARING STOPGAP β read before touching (#176/#177,
+ /// 2026-07-06): this cap BITES in the Facility Hub (366 registered fixtures β
+ /// 238 camera-distance evictions/frame), and the eviction is the CONFIRMED
+ /// mechanism of the #176 purple seam flash + the #177 stair-room light
+ /// pop-in β an in-range torch of a visible cell that ranks past the cap
+ /// drops out of that cell's 8-set, so per-cell Gouraud lighting pops as the
+ /// camera moves. Retail's minimize_object_lighting (0x0054d480) has
+ /// NO global camera-nearest cap. HOWEVER: raising the cap to 1024 was
+ /// live-tested 2026-07-06 and REVERTED β with the full pool active, three
+ /// unported retail lighting semantics dominate the frame: (a) lights reach
+ /// THROUGH solid floors/walls (retail registers lights per-CELL via
+ /// insert_light 0x0054d1b0 β a portal's purple light below never
+ /// touches the corridor above; our flat sphere-overlap selection has no
+ /// reach/occlusion notion), (b) stationary weenie fixtures ride the DYNAMIC
+ /// 1/d falloff (~9Γ stronger at 3 m than retail's static 1/dΒ³ bake curve),
+ /// (c) an unexplained striped z-fight-like artifact on lit floor regions
+ /// (user screenshot, launch-176-texflush session). The proper fix is the
+ /// A7 dungeon-lighting arc: per-cell light registration + the static curve
+ /// for fixtures + the stripe hunt, THEN uncap. Register row AP-85; desired
+ /// end-state pin (currently Skip):
+ /// LightManagerTests.PointSnapshot_HubScaleLightCount_ObjectSelectionIsCameraInvariant.
+ public const int MaxGlobalLights = 128;
private readonly List _pointSnapshot = new();
diff --git a/tests/AcDream.Core.Tests/Lighting/LightManagerTests.cs b/tests/AcDream.Core.Tests/Lighting/LightManagerTests.cs
index 0bf02967..801b50d7 100644
--- a/tests/AcDream.Core.Tests/Lighting/LightManagerTests.cs
+++ b/tests/AcDream.Core.Tests/Lighting/LightManagerTests.cs
@@ -271,7 +271,13 @@ public sealed class LightManagerTests
/// end-to-end property: a light in range of an object stays selected no
/// matter where the camera is, at Facility-Hub-scale light counts.
///
- [Fact]
+ [Fact(Skip = "#176/#177: the camera-invariant pool is the DESIRED retail end-state " +
+ "(minimize_object_lighting has no global cap), but uncapping was live-tested " +
+ "2026-07-06 and reverted β it exposes unported per-cell light-reach semantics " +
+ "(through-floor light), the dynamic-vs-static falloff misassignment for weenie " +
+ "fixtures, and an unexplained striped floor artifact. Un-skip when the A7 " +
+ "dungeon-lighting arc lands per-cell registration (insert_light 0x0054d1b0) " +
+ "and raises MaxGlobalLights. See ISSUES #176/#177 + register row AP-85.")]
public void PointSnapshot_HubScaleLightCount_ObjectSelectionIsCameraInvariant()
{
var mgr = new LightManager();
diff --git a/tests/AcDream.Core.Tests/Rendering/Issue176177DungeonSeamInspectionTests.cs b/tests/AcDream.Core.Tests/Rendering/Issue176177DungeonSeamInspectionTests.cs
index ff6f4633..e861f5fc 100644
--- a/tests/AcDream.Core.Tests/Rendering/Issue176177DungeonSeamInspectionTests.cs
+++ b/tests/AcDream.Core.Tests/Rendering/Issue176177DungeonSeamInspectionTests.cs
@@ -233,6 +233,94 @@ public class Issue176177DungeonSeamInspectionTests
}
}
+ ///
+ /// #176 THE STRIPES (user screenshot, 2026-07-06 evening): a floor region
+ /// z-fights in regular bands between a purple-lit copy and an unlit copy β
+ /// two COINCIDENT DRAWN surfaces with different per-cell light sets. This
+ /// sweep hunts the pair in the dat: every pair of DRAWN polys across the
+ /// corridor neighborhood that is coplanar AND overlapping in area. Before
+ /// the light-cap fix both copies were usually equally unlit (the purple
+ /// portal light was cap-evicted) so the fight was invisible; the stable
+ /// light exposed it.
+ ///
+ [Fact]
+ public void CorridorNeighborhood_CoplanarOverlappingDrawnPolyPairs()
+ {
+ var datDir = ResolveDatDir();
+ if (datDir is null) { _out.WriteLine("SKIP: no dat dir"); return; }
+ using var dats = new DatCollection(datDir, DatAccessType.Read);
+
+ // Seed cells around the screenshot location (the 016E/017A seam) +
+ // one portal ring.
+ var cellIds = new HashSet { 0x8A020165u, 0x8A02016Eu, 0x8A02017Au };
+ foreach (var seed in new List(cellIds))
+ {
+ var seedCell = dats.Get(seed);
+ if (seedCell is null) continue;
+ foreach (var p in seedCell.CellPortals)
+ cellIds.Add(0x8A020000u | p.OtherCellId);
+ }
+
+ // Collect all DRAWN polys world-space per cell.
+ var drawn = new List<(uint CellId, ushort PolyId, Vector3 N, float D,
+ Vector3 Min, Vector3 Max, uint SurfaceId)>();
+ foreach (var cellId in cellIds)
+ {
+ var loaded = LoadCell(dats, cellId);
+ if (loaded is null) continue;
+ var (cell, cs) = loaded.Value;
+ var world = WorldTransform(cell);
+
+ foreach (var (id, poly) in cs.Polygons)
+ {
+ if (!WouldDraw(poly, cell)) continue;
+ var w = WorldVerts(cs, poly, world);
+ if (w.Count < 3) continue;
+ var n = Vector3.Normalize(Vector3.Cross(w[1] - w[0], w[2] - w[0]));
+ float d = Vector3.Dot(n, w[0]);
+ var min = new Vector3(float.MaxValue); var max = new Vector3(float.MinValue);
+ foreach (var v in w) { min = Vector3.Min(min, v); max = Vector3.Max(max, v); }
+ uint surfaceId = 0x08000000u | (uint)cell.Surfaces[poly.PosSurface];
+ drawn.Add((cellId, id, n, d, min, max, surfaceId));
+ }
+ }
+ _out.WriteLine($"cells={cellIds.Count} drawnPolys={drawn.Count}");
+
+ int pairs = 0;
+ for (int i = 0; i < drawn.Count; i++)
+ {
+ for (int j = i + 1; j < drawn.Count; j++)
+ {
+ var a = drawn[i]; var b = drawn[j];
+ if (a.CellId == b.CellId && a.PolyId == b.PolyId) continue;
+
+ float align = Vector3.Dot(a.N, b.N);
+ if (MathF.Abs(align) < 0.999f) continue;
+ float dB = align > 0 ? b.D : -b.D;
+ if (MathF.Abs(a.D - dB) > 0.02f) continue; // same plane within 2 cm
+
+ // Overlap in world AABB, with meaningful area in the plane.
+ float ox = MathF.Min(a.Max.X, b.Max.X) - MathF.Max(a.Min.X, b.Min.X);
+ float oy = MathF.Min(a.Max.Y, b.Max.Y) - MathF.Max(a.Min.Y, b.Min.Y);
+ float oz = MathF.Min(a.Max.Z, b.Max.Z) - MathF.Max(a.Min.Z, b.Min.Z);
+ if (ox < 0.05f || oy < 0.05f) continue;
+ // For horizontal planes require XY overlap area; for walls allow thin Z.
+ bool horizontal = MathF.Abs(a.N.Z) > 0.85f;
+ if (horizontal && ox * oy < 0.05f) continue;
+ if (!horizontal && oz < 0.05f) continue;
+
+ pairs++;
+ _out.WriteLine(
+ $">>> COPLANAR-OVERLAP {(a.CellId == b.CellId ? "SAME-CELL" : "CROSS-CELL")}: " +
+ $"0x{a.CellId:X8} poly {a.PolyId} (surf 0x{a.SurfaceId:X8}) <-> " +
+ $"0x{b.CellId:X8} poly {b.PolyId} (surf 0x{b.SurfaceId:X8}) " +
+ $"n=({a.N.X:F2},{a.N.Y:F2},{a.N.Z:F2}) align={align:F3} " +
+ $"overlap x={ox:F2} y={oy:F2} z=[{MathF.Max(a.Min.Z, b.Min.Z):F2}..{MathF.Min(a.Max.Z, b.Max.Z):F2}]");
+ }
+ }
+ _out.WriteLine($"coplanar overlapping drawn pairs: {pairs}");
+ }
+
///
/// #176 candidate (A2C): the opaque pass derives GL_SAMPLE_ALPHA_TO_COVERAGE
/// from the sampled texture alpha (mesh_modern.frag uRenderPass==0 keeps
@@ -379,6 +467,9 @@ public class Issue176177DungeonSeamInspectionTests
[InlineData(0x8A02011Du)]
[InlineData(0x8A020122u)]
[InlineData(0x8A02011Fu)]
+ [InlineData(0x8A02016Eu)] // corridor cells β the striped-floor screenshot area
+ [InlineData(0x8A02017Au)]
+ [InlineData(0x8A020165u)]
public void UnderHall_DrawnPolys_SurfaceColors(uint cellId)
{
var datDir = ResolveDatDir();