Picked tfrag morph targets from the open list and found the premise was wrong.
There are no morph targets in this format. Morphing is a blend toward the midpoint
of the vertex's two PARENT vertices -- g[parent1_position] and
g[parent2_position] -- which are other vertices in the same tfrag. The engine
implements exactly that in resolve_vertex, and it is covered by
morphing_blends_toward_the_parent_midpoint plus
morph_weight_runs_from_zero_to_one_across_its_band and
collapse_distances_are_the_far_edge_of_each_band. So "morph targets unrecovered"
was never a gap; it named a thing that does not exist in the format.
Strip bookkeeping is likewise already there: TfragStrip carries
vertex_count_and_flag, and tfrag_triangles walks the strip command lists and index
arrays to build triangles. That was the other half of the same roadmap entry.
Coverage, all passing: 36 tfrag tests, 9 texture tests, 23 gc-engine tests. The
real-disc texture test decodes all 1595 level textures, with pixels and mip levels,
so the module doc's "not yet recovered: the texel data the texture table points
into" is also stale.
Two stale claims corrected:
1. crates/gc-formats/src/tfrag.rs said "Not yet recovered: the LOD switch and morph
rules in TfragProc, and the texel data the texture table points into. See
docs/plan/tfrag.md." The rules are recovered and tested, the texels are
decoded, and docs/plan/tfrag.md DOES NOT EXIST -- a dangling reference to a
file that was never written.
2. docs/roadmap.md marked tfrag partial with "Still open: morph targets and the
strip/chain bookkeeping". Neither is open.
The honest replacement for both is what is genuinely not claimed: the LOD switch
distances, morph weight and collapse edge are DERIVED from the data -- tiers are
classified from the four V4_8 parent arrays, the weight runs zero to one across
each tier's band -- but have not been checked against PCSX2 the way the lighting
pass was. That is a verification gap, not a parsing gap, and it needs a frame
captured at a known view distance rather than more disc-side measurement.
ReaperOfVeriod
6d0c1b6fd1