GoldenFixtureMatchesCSharp draws arguments only under CULTMATH_WRITE_GLSL=1: the draw calls MathF.Pow,
whose bits differ by OS. Checking decodes each committed case's arguments and evaluates C# on them.
phacelle is compared across platforms within 2^-20 max(|v|, 1) per component; iv_exp keeps one ulp.
The iv_frustum_ball check gains the upper side r + d + 2^-19 (r + |c|_1) that NoiseBoundTests pins.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>