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swiftshader
Commit 5c372082 by Nicolas Capens Committed by Nicolas Capens
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Clarify the PointCoord calculation

Bug: b/149537975 Change-Id: Ia589e0015437e5257991fe2e8b5f6459384a76de Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/42048 Presubmit-Ready: Nicolas Capens <nicolascapens@google.com> Kokoro-Presubmit: kokoro <noreply+kokoro@google.com> Tested-by: 's avatarNicolas Capens <nicolascapens@google.com> Reviewed-by: 's avatarAlexis Hétu <sugoi@google.com>
parent 653b9cba
Showing with 5 additions and 4 deletions
src/Pipeline/PixelProgram.cpp
......@@ -88,10 +88,11 @@ void PixelProgram::setBuiltins(Int &x, Int &y, Float4 (&z)[4], Float4 &w, Int cM
routine.setInputBuiltin(spirvShader, spv::BuiltInPointCoord, [&](const SpirvShader::BuiltinMapping &builtin, Array<SIMD::Float> &value) {
assert(builtin.SizeInComponents == 2);
Float pointSizeFactor = *Pointer<Float>(primitive + OFFSET(Primitive, pointSizeInv));
value[builtin.FirstComponent + 0] = SIMD::Float(0.5f) + SIMD::Float(pointSizeFactor) * (((SIMD::Float(Float(x)) + SIMD::Float(0.f, 1.f, 0.f, 1.f)) - SIMD::Float(*Pointer<Float>(primitive + OFFSET(Primitive, pointCoordX)))));
value[builtin.FirstComponent + 1] = SIMD::Float(0.5f) + SIMD::Float(pointSizeFactor) * (((SIMD::Float(Float(y)) + SIMD::Float(0.f, 0.f, 1.f, 1.f)) - SIMD::Float(*Pointer<Float>(primitive + OFFSET(Primitive, pointCoordY)))));
// PointCoord formula reference: https://www.khronos.org/registry/vulkan/specs/1.2/html/vkspec.html#primsrast-points-basic
// Note we don't add a 0.5 offset to x and y here (like for fragCoord) because pointCoordX/Y have 0.5 subtracted as part of the viewport transform.
SIMD::Float pointSizeInv = SIMD::Float(*Pointer<Float>(primitive + OFFSET(Primitive, pointSizeInv)));
value[builtin.FirstComponent + 0] = SIMD::Float(0.5f) + pointSizeInv * (((SIMD::Float(Float(x)) + SIMD::Float(0.0f, 1.0f, 0.0f, 1.0f)) - SIMD::Float(*Pointer<Float>(primitive + OFFSET(Primitive, pointCoordX)))));
value[builtin.FirstComponent + 1] = SIMD::Float(0.5f) + pointSizeInv * (((SIMD::Float(Float(y)) + SIMD::Float(0.0f, 0.0f, 1.0f, 1.0f)) - SIMD::Float(*Pointer<Float>(primitive + OFFSET(Primitive, pointCoordY)))));
});
routine.setInputBuiltin(spirvShader, spv::BuiltInSubgroupSize, [&](const SpirvShader::BuiltinMapping &builtin, Array<SIMD::Float> &value) {
......
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