The probe launch discriminated it: the user reproduced the purple floor
flash while [light] (ambient branch) and [pv-input] (portal flood) read
provably healthy — eliminating the last CPU-side theories and exposing
the one channel the probes could not see: per-cell 8-light set
composition.
BuildPointLightSnapshot kept the MaxGlobalLights=128 point lights
nearest THE CAMERA; the Facility Hub registers 366 fixtures, so 238
were evicted per frame by camera distance. SelectForObject (faithfully
camera-independent, and unit-pinned as such) could only choose from the
surviving 128 — an in-range torch of a visible cell that ranked past
the cap dropped out of that cell's 8-set, so per-cell Gouraud lighting
flipped as the chase boom swung the camera:
- #176: the flipping unit is a CELL -> discontinuity lines at exactly
cell-seam granularity; a torch-losing floor drops to dim blue-grey
stone at 0.2 ambient (the perceived purple), camera-angle dependent.
- #177: a stair room whose torches all ranked past the cap rendered at
bare 0.2 ambient (near-black = 'not visible'); approach re-admitted
them ('pops into existence'); the sweeping boundary dropped the
ramp's lights mid-descent ('disappears on the last step'). The
geometry never vanished - its lights did.
Retail's minimize_object_lighting (0x0054d480) has NO global
camera-nearest pool cap (lights register per cell, insert_light
0x0054d1b0). Fix: MaxGlobalLights 128 -> 1024, a non-biting safety
valve (GlobalLightPacker grows to fit; 64 B/light). Register row AP-85.
TDD pin: PointSnapshot_HubScaleLightCount_ObjectSelectionIsCameraInvariant
(RED at 128 with a Hub-scale 401-light layout, GREEN at 1024). The
pre-existing camera-independence pin covered the SELECTOR but not the
SNAPSHOT it selects from - the pop re-entered one stage upstream.
Suites: Core 2588 / App 719 / UI 425 / Net 385 green. Pending user gate.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The dungeon render pair (purple seam flash + stair pop-in) resisted
desk root-causing, but the investigation narrowed the space to two
live theories and shipped permanent apparatus:
- Issue176177DungeonSeamInspectionTests: dat truth — corridor floors
ARE textured drawn PortalSide portal polys; the reciprocal is NoPos;
the 'stairs' are 0x8A020182's ramp shell (vertical portals, zero
statics); CellBSP partitions exactly at portal planes; DXT1 textures
carry zero transparent-mode texels.
- Issue176177FacilityHubFloodReplayTests: production-matched flood
replays — approach/descent/gaze-sweep/walk all healthy with coherent
inputs; ScenarioE pins the flood's collapse-to-root sensitivity under
incoherent (root, eye) pairs.
- Issue176177SeamTransitLagTests: the resolver flips cells within one
tick-step of the portal plane — the 0.33-0.47m [cell-transit] 'lag'
in the gate logs is speed*tick quantization, not membership error.
Refuted (do NOT retry — ledger in the research doc): placeholder
texture, reciprocal z-fight, seal z-fight (seals only fire for
OtherCellId==0xFFFF), root/eye incoherence (production camera sweep is
mm-exact at planes), flood bistability, #119-class statics, undefined
DXT mips (both paths decode DXT->RGBA8; the compressed-array branch is
dead code), DXT1 alpha, fog mix (ramp ~538m), lightning leak (flash==0
in production), viewer-light pops (smooth (1-d/range) ramp).
Filed #178 (A8 double-sided shell stopgap still live) and #179
(lightning flash lacks an indoor gate — dormant). The purple can only
be the fog clear color (undrawn pixels) or the outdoor ambient+sun
tint; discrimination needs ONE probe launch (ACDREAM_PROBE_LIGHT +
ACDREAM_PROBE_PVINPUT + ACDREAM_PROBE_CELL) — protocol in
docs/research/2026-07-06-176-177-render-pair-investigation.md.
Suites: Core 2587 / App 719 green.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
