The seam-floor purple flicker was NOT a draw z-fight. The in-engine
[seam-*] probe (ACDREAM_PROBE_SEAMDRAW - built because RenderDoc cannot
capture this pipeline: it hides GL_ARB_bindless_texture and the
mandatory-modern startup gate throws; AMD GPU rules out Nsight) killed
every double-draw suspect: ONE shell instance per seam cell at the
lifted z, no floor-coincident entity (portal entities sit at z=-12.05),
zero portal depth fans in the sealed Hub. What it caught instead: the
corridor floor's applied light set flipping wholesale with the flood.
Root cause: c500912b scoped BuildPointLightSnapshot by the per-frame
portal flood, on the research doc's gloss of CEnvCell::visible_cell_table
as "the portal-flood visible set". The named decomp refutes the gloss:
add_visible_cell (0x0052de40) DBObj-LOADS absent cells and inserts them;
a cell activation adds itself + its whole dat visible-cell list
(0x0052e228/0x0052e24a); entries leave only via the flush machinery.
It is the RESIDENT-cell registry - gaze can never remove a cell.
add_dynamic_lights (0x0052d410) walks the WHOLE table per frame
(caller 0x00452d30), and insert_light (0x0054d1b0) caps the pool by
distance to Render::player_pos (0x0054d1dd). Retail's pool is a function
of player position only. Ours followed the camera: turning changed the
flood (probe: 8..41 cells across one turn), the six intensity-100
under-room portal purples entered/left the pool, and the wedge blinked.
Fix: BuildPointLightSnapshot(playerWorldPos) collects ALL registered
(=resident) lit lights; over cap keeps dynamics FIRST (retail's separate
7-slot dynamic pool never competes with statics) then nearest-the-player;
the RebuildScopedLights callback is deleted. Live-verified with the probe:
full-circle turn, flood churning 8..41, the floor set held the same 8
identities on every post-spawn frame. The purple wedge SHAPE stays - it
is cdb-proven retail-faithful.
Residual deviation (AP-85 rewritten): single 128 pool vs retail's
7-dynamic/40-static degrade-scaled dual pools - the Hub now shows
7 purples + viewer where retail's cdb showed 4 + viewer + fixture slots;
if the gate reads the wedge as too purple, the A7 dual-pool cap is the
faithful trim.
Pins: PointSnapshot_HubScaleLightCount_ObjectSelectionIsCameraInvariant
(rewritten to the corrected model),
PointSnapshot_OverCap_DynamicsNeverEvictedByNearerStatics,
PointSnapshot_OverCap_KeepsNearestThePlayer,
PointSnapshot_ResidentCollection_CellTagDoesNotFilter.
Suites: Core 2599+2skip / App 726+2skip / UI 425 / Net 385.
The [seam-*] probes stay until the visual gate passes, then strip.
Correction banner added to 2026-07-06-a7-per-cell-lighting-pseudocode.md;
outcome banner on the z-fight handoff; ISSUES #176 updated.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
cdb trace of LIVE retail (tools/cdb/issue176-floor-light.cdb, binary<->PDB MATCH) PROVED retail
applies ALL its dynamic lights — 4 intensity-100 magenta portal lights (d3dIdx 3-6, falloff 6) +
the viewer fill (d3dIdx 1, 2.25) — as D3D hardware lights to EVERY Facility Hub cell, every frame,
stable. So the faceted purple wedges on the floor are retail-FAITHFUL. acdream did a per-cell
SelectForObject sphere-overlap 8-cap for cells, so the portal set could differ/flip per cell.
- LightManager.SelectForCell (retail minimize_envcell_lighting 0x0054c170): ALL dynamic lights
applied unconditionally (shader range cutoff zeroes non-reaching = D3D hardware range), then
nearest static torches fill remaining slots. Wired into EnvCellRenderer.GetCellLightSet.
Objects keep SelectForObject (minimize_object_lighting). Pins:
SelectForCell_AppliesAllDynamicLights_EvenOutOfReach + _SameDynamicSet_ForCellsFarApart_NoFlap.
- Apparatus: [light-detail] gains owner/cell/dyn (pinned the culprit = 2 portal weenies
0x000F4247/48 in 0x8A020118/19, intensity=100 magenta); CellVertexNormals_SmoothOrFaceted_Dump
(corridor floor uses SMOOTH per-vertex dat normals, not flat); tools/cdb/issue176-floor-light.cdb.
#176 RESIDUAL is NOT this fix. It's a RUNTIME draw z-fight in the seam floor. Eliminated (evidence):
NOT lighting (per-light cap + this both no-change), NOT membership (render cell 0x8A020164 stable
100% of 188k frames / 526 angles, res=None), NOT dat geometry (coplanar sweep empty at z=-6 floor
incl. cell 0164). NEXT = RenderDoc pixel-history. Full handoff + DO-NOT-RETRY:
docs/research/2026-07-06-176-seam-floor-zfight-handoff.md. Suites green: Core 2599 + 2 skip.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
