Files
Syplheed-Reborn/crates/sylpheed-formats/tests
MechaCat02 578c71a1b9 [formats,viewer] Decode grouped-pool XBG7 models; fix mesh routing + albedo
Revert the mis-guided "triangle STRIP" reading (a937779): XBG7 index
buffers are triangle LISTS (prim=4 in the GPU capture; stored-normal
agreement 1.000 as a list vs ~0.49 as a strip). Reinstate the
winding-consistency gate.

Crack the grouped-pool layout used by the hero ship and ~150 detailed
models. A resource's sub-meshes share one index pool (buffers 4-byte
aligned, in descriptor-marker order) followed by one vertex pool (each
vtx_count*stride, same order); the vertex pool is 4-byte aligned after
the index pool. The whole resource is derived from one anchored pivot:
  ib0 = vb0 - span - pad   (pad in 0..=3, alignment)
  ib[i] = align4(ib[i-1] + idx_count[i-1]*2)
  vb[i] = vb[i-1] + vtx_count[i-1]*stride
vb0 is found via the unit-normal vertex-run scan; the alignment is
confirmed by validating the LARGEST sub-mesh (most reliable), after
which the rest are read/validated. A single marker reduces this to the
existing adjacency anchor, so grouped generalises it.

Results (cross-checked against a Canary GPU draw-log capture of
DeltaSaber_T.xpr):
- DeltaSaber_T f001 = body + 7 detail parts = 8650 tris, every sub-mesh
  0-degenerate / full-coverage / winding-agreement 1.000.
- All 19 previously-declined weapon models now decode (they hit pad 2
  and/or lead with a tiny bracket that broke a markers[0] pivot). Corpus
  audit: 0/146 geometry files fail (was 19 -> flat-texture in the viewer).
- Stages unchanged (single-marker path is byte-identical; grouped falls
  back to the old anchor on failure). 7/7 disc tests green incl. the
  strict stage quality audit; new hero_ship_grouped_pool_decodes test.

Viewer: route by count_xbg7; --only matches an exact model name (so the
neutral pose renders without the mnv*/turn180 animation poses). Fix the
albedo matcher: match a sub-model to its _col map by entity stem
(e007_bdy_01 -> e007_col) instead of a full-name prefix, lifting stage
sub-model texturing from ~25% to ~95% (the rest were flat grey). Colour
correctness (channel order/sRGB) remains a separate dynamic-RE item.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-18 19:54:39 +02:00
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