The morph was recorded as unverifiable because "reading a weight back out of
RAM does not work -- the positions live inside regenerated VU packets". That
is right about the correspondence and wrong about the cause. The cause is
measurable, and it comes back clean:
patches 833
positions 40,600 disc == ram
positions identical 40,600
block bytes differing 166,465
inside a position unpack 0
inside another unpack 49,484
in a VIF command word 116,981
Range: level 0, all 833 tfrag patches, live PINE RAM against the disc. Two
independent measurements agree. Walking the VIF lists on both copies and
comparing parsed positions gives 40,600 identical and zero changed; a raw
per-byte diff of each patch's own extent classifies every differing byte, and
none of them is in a position unpack. The position ranges total 490,224 bytes.
So the blend is not precomputed into the geometry. The rewrites are packet
framing -- 70% command words -- plus other unpack payloads, which is the loader
rebuilding the VIF packet for the tier it selected while leaving the vertices
alone. The morph happens at draw time in the VU stream.
The standing note becomes a sharper one: there was never a correspondence
problem. The values were identical, so there was nothing to read.
gc-trace gains verify-morph, which does both measurements. TfragGeometry
gains position_ranges and other_ranges so the walk needed to classify a diff
is already paid for, and the ranges come from the same walk the rest of the
parse uses rather than a second one that could drift.
Per-patch extents are the gap to the next patch's data pointer. That is exact
and needs no guess about which header field marks a patch's end; the first
attempt at this compared each patch against the whole rest of the region and
reported 65 million differing bytes, which is what an unbounded comparison
looks like.
tfrag_positions_are_verbatim_and_the_rewrites_are_elsewhere is gated on
GC_SSTATE and asserts the four bounds, plus two guards: the rewrites must be
non-trivial (over 100,000 bytes) and mostly command words, so a RAM image that
was a verbatim copy of the disc -- which would make the zero look good for the
wrong reason -- fails instead.
Suite with the disc and GC_SSTATE: 68 disc tests, 156 gc-formats, 22
gc-trace, 23 gc-engine, 19 gc-game. Clippy clean.
ReaperOfVeriod
3a1156d8e1