The stride retraction (e5cd3df) disowned the 16-byte element reading and the
95,612-vertex population that came with it. Two committed tests still compute
exactly those figures and still pass:
tie_vertex_element_is_16_bytes_with_fixed_texcoords
tie_vertex_layout_is_selected_by_i16_3_high_byte
They pass because the arithmetic is self-consistent about a WITHDRAWN population --
the same shape as the chunk uniformity claim, one level up. The parser slices at
16 bytes, the test reads the slices, the numbers agree, and nothing in the loop can
notice the stride is wrong. A green test that cannot fail is the exact failure mode
this session has been cataloguing, and here it was left in place by someone else's
retraction rather than mine.
Both are KEPT and marked, for a specific reason: each is the record of what the
16-byte reading produces, so the retraction is visibly about the stride rather
than about the arithmetic. Deleting or renaming them would erase the thing the
retraction is a retraction OF, and there would be no way to check later that the
numbers moved because the layout changed rather than because someone edited a
constant.
The marking says, at the top of both:
Do not quote the 82.5% figure as a property of tie vertices. It is a property
of one reading of the vertex region, on a population the retraction disowned.
TWO DENOMINATORS, BOTH CORRECT, 92.9% APART
The layout test reports (4,5) as 12-bit fixed on 92.9% OF VERTICES. A separate
measurement on flat records found only 16 of 1,488 DISTINCT i16[4] values are
multiples of 4096.
Both are right. Most vertices use the handful of UV-corner values -- (0,0),
(0,4096), (4096,4096), (4096,0) -- which are all multiples of 4096, so the
per-vertex rate is high. The other 1,472 are not, so the per-distinct-value rate is
1%.
That gap IS the artifact, and naming both denominators is the most useful thing
available about it. A percentage over vertices and a percentage over distinct
values answer different questions, and only one of them was ever asked about --
which is the same base-rate error as the class-ID slot, where a bound that selected
for small numbers made nine values look like 305x enrichment.
268 tests.
ReaperOfVeriod
7b6de36958