softgpu: Correct accuracy of MODULATE texfunc.

This matches hardware tests for every value of A * B.
Interesting that it's a different formula than alpha blend.
This commit is contained in:
Unknown W. Brackets 2021-12-05 12:06:52 -08:00
parent 197897979a
commit 73460f7461

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@ -278,17 +278,19 @@ Vec4IntResult SOFTRAST_CALL GetTextureFunctionOutput(Vec4IntArg prim_color_in, V
case GE_TEXFUNC_MODULATE:
{
#if defined(_M_SSE)
// We can be accurate up to 24 bit integers, should be enough.
const __m128 p = _mm_cvtepi32_ps(prim_color.ivec);
const __m128 t = _mm_cvtepi32_ps(texcolor.ivec);
const __m128 b = _mm_mul_ps(p, t);
// Modulate weights slightly on the tex color, by adding one to prim and dividing by 256.
const __m128i p = _mm_slli_epi16(_mm_packs_epi32(prim_color.ivec, prim_color.ivec), 4);
const __m128i pboost = _mm_add_epi16(p, _mm_set1_epi16(1 << 4));
__m128i t = _mm_slli_epi16(_mm_packs_epi32(texcolor.ivec, texcolor.ivec), 4);
if (gstate.isColorDoublingEnabled()) {
// We double right here, only for modulate. Other tex funcs do not color double.
const __m128 doubleColor = _mm_setr_ps(2.0f / 255.0f, 2.0f / 255.0f, 2.0f / 255.0f, 1.0f / 255.0f);
out_rgb.ivec = _mm_cvtps_epi32(_mm_mul_ps(b, doubleColor));
} else {
out_rgb.ivec = _mm_cvtps_epi32(_mm_mul_ps(b, _mm_set_ps1(1.0f / 255.0f)));
const __m128i amask = _mm_set_epi16(-1, 0, 0, 0, -1, 0, 0, 0);
const __m128i a = _mm_and_si128(t, amask);
const __m128i rgb = _mm_andnot_si128(amask, t);
t = _mm_or_si128(_mm_slli_epi16(rgb, 1), a);
}
const __m128i b = _mm_mulhi_epi16(pboost, t);
out_rgb.ivec = _mm_unpacklo_epi16(b, _mm_setzero_si128());
if (rgba) {
return ToVec4IntResult(Vec4<int>(out_rgb.ivec));
@ -297,11 +299,11 @@ Vec4IntResult SOFTRAST_CALL GetTextureFunctionOutput(Vec4IntArg prim_color_in, V
}
#else
if (gstate.isColorDoublingEnabled()) {
out_rgb = (prim_color.rgb() * texcolor.rgb() * 2) / 255;
out_rgb = ((prim_color.rgb() + Vec3<int>::AssignToAll(1)) * texcolor.rgb() * 2) / 256;
} else {
out_rgb = prim_color.rgb() * texcolor.rgb() / 255;
out_rgb = (prim_color.rgb() + Vec3<int>::AssignToAll(1)) * texcolor.rgb() / 256;
}
out_a = (rgba) ? (prim_color.a() * texcolor.a() / 255) : prim_color.a();
out_a = (rgba) ? ((prim_color.a() + 1) * texcolor.a() / 256) : prim_color.a();
#endif
break;
}