gunRenderFirstPersonGunModels built its ModelRenderData with
renderdata = *(ModelRenderData *)&D_80035CC0;
a reinterpret that reads the lone `u32 D_80035CC0 = 0` and continues into the
next declared global `u32 D_80035CC4[] = {1, 3, 0, ...}` (gun.c). On N64 that
yields { basemtx=0, zbufferenabled=1, flags=3, rest=0 } because the linker
lays the two globals out contiguously in declaration order and pointers are
4 bytes. On x86-64 it breaks twice: ModelRenderData's pointer members widen
4->8 B (so `flags` is no longer at struct offset 8) and C guarantees nothing
about the two globals' placement. Measured (GE_DVM=1, BUNKER1): flags == 0,
which gates every weapon-model DL node off in modelRenderNodeGundl
((renderdata->flags & 1)) -> subdraw emits 1 gfx command instead of ~150 ->
no gun visible while playing.
All three VIEWMODEL-RESEARCH.md ranked suspects were ruled out first by the
same probe: field_87F==1, RootNode valid, numRecords 22 < pool 192, node walk
visits 24+ valid DL/SWITCH/BSP nodes.
Fix: #ifdef PORT -> set the fields explicitly (zbufferenabled=TRUE; flags=3);
N64 line verbatim under #else. ABI/layout only (D3x class), no logic change.
Verified (headless): GE_DVM=1 post-fix shows flags=0x3 and the weapon subdraw
now emits 153 gfx commands (was 1); bunker1 framediff worst_cell 12.2 -> 28.5
(gun renders in-frame); Dam/Facility/Bunker1/Archives/Cradle/Aztec sweep
crash-free. Owed: one BUNKER1 eyeball; the bunker1 golden needs re-baselining.
GE_DVM gate+render probes left in, env-gated (cf. GE_D193*).
findings.md D215 + index; GRAPHICS-BACKLOG + VIEWMODEL-RESEARCH marked 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