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VideoCore: Implement the DOT3_RGB combiner

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Lectem 2015-05-14 15:49:40 +02:00 committed by Yuri Kunde Schlesner
parent 2501f111a6
commit d08e9b29e2
2 changed files with 13 additions and 1 deletions
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1
src/video_core/pica.h
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@ -290,6 +290,7 @@ struct Regs {
AddSigned = 3,
Lerp = 4,
Subtract = 5,
Dot3_RGB = 6,
MultiplyThenAdd = 8,
AddThenMultiply = 9,

13
src/video_core/rasterizer.cpp
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@ -641,7 +641,18 @@ static void ProcessTriangleInternal(const VertexShader::OutputVertex& v0,
result = (result * input[2].Cast<int>()) / 255;
return result.Cast<u8>();
}
case Operation::Dot3_RGB:
{
// Not fully accurate.
// Worst case scenario seems to yield a +/-3 error
// Some HW results indicate that the per-component computation can't have a higher precision than 1/256,
// while dot3_rgb( (0x80,g0,b0),(0x7F,g1,b1) ) and dot3_rgb( (0x80,g0,b0),(0x80,g1,b1) ) give different results
int result = ((input[0].r() * 2 - 255) * (input[1].r() * 2 - 255) + 128) / 256 +
((input[0].g() * 2 - 255) * (input[1].g() * 2 - 255) + 128) / 256 +
((input[0].b() * 2 - 255) * (input[1].b() * 2 - 255) + 128) / 256;
result = std::max(0, std::min(255, result));
return { (u8)result, (u8)result, (u8)result };
}
default:
LOG_ERROR(HW_GPU, "Unknown color combiner operation %d\n", (int)op);
UNIMPLEMENTED();