The GE keeps the specular and spot exponents to 5 significant bits,
truncated, and from 512 up (infinity and NaN included) uses 496. Only
the specular one was truncated, and neither saturated. A huge or NaN
exponent overflowed pspPow's bits: highlights wrong on every backend,
and on D3D11, where the overflowing float to int conversion gives a
NaN, black (Everybody's Golf, #22418). With the exponent clamped, t
stays in range for every base the backends produce.
Measured, now bit exact in the software renderer and within 4 levels
on Vulkan.
Fixes#22418
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
The minor-axis offset an antialiased line's alpha comes from is computed
with the triangle setup's reciprocal of the line's major length, walking
from v0, and floored; diagonal lines are y-major. exp112 went from 101
differing pixels to 23; the misses left sit at reciprocal segment starts.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Nearly every segment's K is floor(2^39 / (65536 + 256 i) / 16) * 16. The
fit to probe data left a few segments loose and slightly low; segment 39
made Blade Dancer's large triangle one depth unit high where the PSP's
depth test rejects it (frame dump now exact). Segments 39, 162, 253 and 255
now use the formula, which every probe accepts.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Segment 161's K was 16 low: exp54's one inexact Gouraud triangle needs
q >= 40211 at index 41275 (its y gradient -1366), and exp39/exp41 bound K
from above, leaving a window of 16 that the depth-only fit had missed. Every
color and depth probe is now exact.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
The exponent times the log (the float's bits) keeps units of 16 in the bits,
truncated toward zero, not floored at 1. Fixes the last specular pixels at
small exponents (gpu/probe exp102 e = 0.3, exp3, exp4 e = 0.05); all lighting
probes are now bit exact.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
The GE arithmetic in GEMath.h against values measured on a PSP: the
reciprocal for sampled mantissas (gpu/probe exp15), the triangle setup
reciprocal (exp38-41), antialiased line alphas (exp112), and the cases the
other probes pinned down (float24 truncation, the adder and row sums, rsqrt,
the mip log2, texture coordinate precision, the lighting pow and color
scaling).
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
