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>
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