Cloud tile is s_skywaterimages[0] = 64x64 IA8, G_TX_WRAP -> it tiles.
GE's screen-space textured-quad idiom is tc = width<<5 (glass2.c:678), so
skyPortRenderPoly's *32.0f scale was correct; the bug was (s16) overflow on
the +/-20k-texel horizon S/T (unk20/unk24 are texel coords, not fractions).
Fix: fold every vertex of one primitive by the same multiple of the 64-texel
tile period before scaling. Inter-vertex deltas (hence the interpolated
cloud texture) are preserved; magnitudes stay in s16 range. Exact for any
triangle whose S/T span is < ~1000 texels -- everything except tris
straddling the horizon line, which are Defect 2 (adaptive tessellation).
sky.c #ifdef PORT only; N64 path unchanged. Builds clean; bunker1 + statue
verify PASS, no crash. UNVERIFIED VISUALLY -- owed: one -level_22 screenshot
(D176a-SKY-NOTES.md 'Verification ask').
Also: rebased onto main (porting-notes.md conflict resolved).
All referenced from HANDOFF.md / GRAPHICS-BACKLOG.md but untracked:
- D172-PARTICLE-COLOR-RESEARCH.md: magenta/cyan blood root-cause candidate
(unhandled GBI opcode 0xB9 in ROM particle records + D146 guard)
- D176a-SKY-NOTES.md: RDPHALF sky-tri wire format decoded; Path B draft state
- VIEWMODEL-RESEARCH.md: 1P weapon model static audit, three ranked suspects
- QOL-INVENTORY.md / WIDESCREEN-FOV-PLAN.md / UNLOCKED-FPS-PLAN.md: parked
Phase-4 proposals
James Dansereau