src/Pipeline/PixelProgram.cpp - SwiftShader - Git at Google

 // Copyright 2016 The SwiftShader Authors. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //    http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 #include "PixelProgram.hpp"

 #include "Constants.hpp"
 #include "SamplerCore.hpp"
 #include "Device/Primitive.hpp"
 #include "Device/Renderer.hpp"
 #include "Vulkan/VkDevice.hpp"

 namespace sw {

 PixelProgram::PixelProgram(
     const PixelProcessor::State &state,
     const vk::PipelineLayout *pipelineLayout,
     const SpirvShader *spirvShader,
     const vk::DescriptorSet::Bindings &descriptorSets)
     : PixelRoutine(state, pipelineLayout, spirvShader, descriptorSets)
 {
 }

 // Union all cMask and return it as Booleans
 SIMD::Int PixelProgram::maskAny(Int cMask[4], const SampleSet &samples)
 {
 	// See if at least 1 sample is used
 	Int maskUnion = 0;
 	for(unsigned int q : samples)
 	{
 		maskUnion |= cMask[q];
 	}

 	// Convert to Booleans
 	SIMD::Int laneBits = SIMD::Int([](int i) { return 1 << i; });  // 1, 2, 4, 8, ...
 	SIMD::Int mask(maskUnion);
 	mask = CmpNEQ(mask & laneBits, 0);
 	return mask;
 }

 // Union all cMask/sMask/zMask and return it as Booleans
 SIMD::Int PixelProgram::maskAny(Int cMask[4], Int sMask[4], Int zMask[4], const SampleSet &samples)
 {
 	// See if at least 1 sample is used
 	Int maskUnion = 0;
 	for(unsigned int q : samples)
 	{
 		maskUnion |= (cMask[q] & sMask[q] & zMask[q]);
 	}

 	// Convert to Booleans
 	SIMD::Int laneBits = SIMD::Int([](int i) { return 1 << i; });  // 1, 2, 4, 8, ...
 	SIMD::Int mask(maskUnion);
 	mask = CmpNEQ(mask & laneBits, 0);
 	return mask;
 }

 void PixelProgram::setBuiltins(Int &x, Int &y, SIMD::Float (&z)[4], SIMD::Float &w, Int cMask[4], const SampleSet &samples)
 {
 	routine.setImmutableInputBuiltins(spirvShader);

 	// TODO(b/146486064): Consider only assigning these to the SpirvRoutine iff
 	// they are ever going to be read.
 	float x0 = 0.5f;
 	float y0 = 0.5f;
 	float x1 = 1.5f;
 	float y1 = 1.5f;

 	// "When Sample Shading is enabled, the x and y components of FragCoord reflect the
 	//  location of one of the samples corresponding to the shader invocation. Otherwise,
 	//  the x and y components of FragCoord reflect the location of the center of the fragment."
 	if(state.sampleShadingEnabled && state.multiSampleCount > 1)
 	{
 		x0 = VkSampleLocations4[samples[0]][0];
 		y0 = VkSampleLocations4[samples[0]][1];
 		x1 = 1.0f + x0;
 		y1 = 1.0f + y0;
 	}

 	routine.fragCoord[0] = SIMD::Float(Float(x)) + SIMD::Float(x0, x1, x0, x1);
 	routine.fragCoord[1] = SIMD::Float(Float(y)) + SIMD::Float(y0, y0, y1, y1);
 	routine.fragCoord[2] = z[0];  // sample 0
 	routine.fragCoord[3] = w;

 	routine.invocationsPerSubgroup = SIMD::Width;
 	routine.helperInvocation = ~maskAny(cMask, samples);
 	routine.windowSpacePosition[0] = SIMD::Int(x) + SIMD::Int(0, 1, 0, 1);
 	routine.windowSpacePosition[1] = SIMD::Int(y) + SIMD::Int(0, 0, 1, 1);
 	routine.layer = *Pointer<Int>(data + OFFSET(DrawData, layer));

 	// 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)));
 	routine.pointCoord[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, x0)))));
 	routine.pointCoord[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, y0)))));

 	routine.setInputBuiltin(spirvShader, spv::BuiltInViewIndex, [&](const SpirvShader::BuiltinMapping &builtin, Array<SIMD::Float> &value) {
 		assert(builtin.SizeInComponents == 1);
 		value[builtin.FirstComponent] = As<SIMD::Float>(SIMD::Int(routine.layer));
 	});

 	routine.setInputBuiltin(spirvShader, spv::BuiltInFragCoord, [&](const SpirvShader::BuiltinMapping &builtin, Array<SIMD::Float> &value) {
 		assert(builtin.SizeInComponents == 4);
 		value[builtin.FirstComponent + 0] = routine.fragCoord[0];
 		value[builtin.FirstComponent + 1] = routine.fragCoord[1];
 		value[builtin.FirstComponent + 2] = routine.fragCoord[2];
 		value[builtin.FirstComponent + 3] = routine.fragCoord[3];
 	});

 	routine.setInputBuiltin(spirvShader, spv::BuiltInPointCoord, [&](const SpirvShader::BuiltinMapping &builtin, Array<SIMD::Float> &value) {
 		assert(builtin.SizeInComponents == 2);
 		value[builtin.FirstComponent + 0] = routine.pointCoord[0];
 		value[builtin.FirstComponent + 1] = routine.pointCoord[1];
 	});

 	routine.setInputBuiltin(spirvShader, spv::BuiltInSubgroupSize, [&](const SpirvShader::BuiltinMapping &builtin, Array<SIMD::Float> &value) {
 		assert(builtin.SizeInComponents == 1);
 		value[builtin.FirstComponent] = As<SIMD::Float>(SIMD::Int(SIMD::Width));
 	});

 	routine.setInputBuiltin(spirvShader, spv::BuiltInHelperInvocation, [&](const SpirvShader::BuiltinMapping &builtin, Array<SIMD::Float> &value) {
 		assert(builtin.SizeInComponents == 1);
 		value[builtin.FirstComponent] = As<SIMD::Float>(routine.helperInvocation);
 	});
 }

 void PixelProgram::executeShader(Int cMask[4], Int sMask[4], Int zMask[4], const SampleSet &samples)
 {
 	routine.device = device;
 	routine.descriptorSets = data + OFFSET(DrawData, descriptorSets);
 	routine.descriptorDynamicOffsets = data + OFFSET(DrawData, descriptorDynamicOffsets);
 	routine.pushConstants = data + OFFSET(DrawData, pushConstants);
 	routine.constants = device + OFFSET(vk::Device, constants);

 	auto it = spirvShader->inputBuiltins.find(spv::BuiltInFrontFacing);
 	if(it != spirvShader->inputBuiltins.end())
 	{
 		ASSERT(it->second.SizeInComponents == 1);
 		auto frontFacing = SIMD::Int(*Pointer<Int>(primitive + OFFSET(Primitive, clockwiseMask)));
 		routine.getVariable(it->second.Id)[it->second.FirstComponent] = As<SIMD::Float>(frontFacing);
 	}

 	it = spirvShader->inputBuiltins.find(spv::BuiltInSampleMask);
 	if(it != spirvShader->inputBuiltins.end())
 	{
 		ASSERT(SIMD::Width == 4);
 		SIMD::Int laneBits = SIMD::Int(1, 2, 4, 8);

 		SIMD::Int inputSampleMask = 0;
 		for(unsigned int q : samples)
 		{
 			inputSampleMask |= SIMD::Int(1 << q) & CmpNEQ(SIMD::Int(cMask[q]) & laneBits, 0);
 		}

 		routine.getVariable(it->second.Id)[it->second.FirstComponent] = As<SIMD::Float>(inputSampleMask);
 		// Sample mask input is an array, as the spec contemplates MSAA levels higher than 32.
 		// Fill any non-zero indices with 0.
 		for(auto i = 1u; i < it->second.SizeInComponents; i++)
 		{
 			routine.getVariable(it->second.Id)[it->second.FirstComponent + i] = 0;
 		}
 	}

 	it = spirvShader->inputBuiltins.find(spv::BuiltInSampleId);
 	if(it != spirvShader->inputBuiltins.end())
 	{
 		ASSERT(samples.size() == 1);
 		int sampleId = samples[0];
 		routine.getVariable(it->second.Id)[it->second.FirstComponent] =
 		    As<SIMD::Float>(SIMD::Int(sampleId));
 	}

 	it = spirvShader->inputBuiltins.find(spv::BuiltInSamplePosition);
 	if(it != spirvShader->inputBuiltins.end())
 	{
 		ASSERT(samples.size() == 1);
 		int sampleId = samples[0];
 		routine.getVariable(it->second.Id)[it->second.FirstComponent + 0] =
 		    SIMD::Float((state.multiSampleCount > 1) ? VkSampleLocations4[sampleId][0] : 0.5f);
 		routine.getVariable(it->second.Id)[it->second.FirstComponent + 1] =
 		    SIMD::Float((state.multiSampleCount > 1) ? VkSampleLocations4[sampleId][1] : 0.5f);
 	}

 	// Note: all lanes initially active to facilitate derivatives etc. Actual coverage is
 	// handled separately, through the cMask.
 	SIMD::Int activeLaneMask = 0xFFFFFFFF;
 	SIMD::Int storesAndAtomicsMask = maskAny(cMask, sMask, zMask, samples);
 	routine.discardMask = 0;

 	spirvShader->emit(&routine, activeLaneMask, storesAndAtomicsMask, descriptorSets, state.multiSampleCount);
 	spirvShader->emitEpilog(&routine);
 	// At the last invocation of the fragment shader, clear phi data.
 	// TODO(b/178662288): Automatically clear phis through SpirvRoutine lifetime reduction.
 	if(samples[0] == static_cast<int>(state.multiSampleCount - 1))
 	{
 		spirvShader->clearPhis(&routine);
 	}

 	for(int i = 0; i < MAX_COLOR_BUFFERS; i++)
 	{
 		c[i].x = routine.outputs[i * 4 + 0];
 		c[i].y = routine.outputs[i * 4 + 1];
 		c[i].z = routine.outputs[i * 4 + 2];
 		c[i].w = routine.outputs[i * 4 + 3];
 	}

 	clampColor(c);

 	if(spirvShader->getAnalysis().ContainsDiscard)
 	{
 		for(unsigned int q : samples)
 		{
 			cMask[q] &= ~routine.discardMask;
 		}
 	}

 	it = spirvShader->outputBuiltins.find(spv::BuiltInSampleMask);
 	if(it != spirvShader->outputBuiltins.end())
 	{
 		auto outputSampleMask = As<SIMD::Int>(routine.getVariable(it->second.Id)[it->second.FirstComponent]);

 		for(unsigned int q : samples)
 		{
 			cMask[q] &= SignMask(CmpNEQ(outputSampleMask & SIMD::Int(1 << q), SIMD::Int(0)));
 		}
 	}

 	it = spirvShader->outputBuiltins.find(spv::BuiltInFragDepth);
 	if(it != spirvShader->outputBuiltins.end())
 	{
 		for(unsigned int q : samples)
 		{
 			z[q] = routine.getVariable(it->second.Id)[it->second.FirstComponent];
 		}
 	}
 }

 Bool PixelProgram::alphaTest(Int cMask[4], const SampleSet &samples)
 {
 	if(!state.alphaToCoverage)
 	{
 		return true;
 	}

 	alphaToCoverage(cMask, c[0].w, samples);

 	Int pass = 0;
 	for(unsigned int q : samples)
 	{
 		pass = pass | cMask[q];
 	}

 	return pass != 0x0;
 }

 void PixelProgram::blendColor(Pointer<Byte> cBuffer[4], Int &x, Int sMask[4], Int zMask[4], Int cMask[4], const SampleSet &samples)
 {
 	for(int index = 0; index < MAX_COLOR_BUFFERS; index++)
 	{
 		if(!state.colorWriteActive(index))
 		{
 			continue;
 		}

 		auto format = state.colorFormat[index];
 		switch(format)
 		{
 		case VK_FORMAT_R4G4B4A4_UNORM_PACK16:
 		case VK_FORMAT_B4G4R4A4_UNORM_PACK16:
 		case VK_FORMAT_A4R4G4B4_UNORM_PACK16:
 		case VK_FORMAT_A4B4G4R4_UNORM_PACK16:
 		case VK_FORMAT_B5G6R5_UNORM_PACK16:
 		case VK_FORMAT_R5G5B5A1_UNORM_PACK16:
 		case VK_FORMAT_B5G5R5A1_UNORM_PACK16:
 		case VK_FORMAT_A1R5G5B5_UNORM_PACK16:
 		case VK_FORMAT_R5G6B5_UNORM_PACK16:
 		case VK_FORMAT_B8G8R8A8_UNORM:
 		case VK_FORMAT_B8G8R8A8_SRGB:
 		case VK_FORMAT_R8G8B8A8_UNORM:
 		case VK_FORMAT_R8G8B8A8_SRGB:
 		case VK_FORMAT_R8G8_UNORM:
 		case VK_FORMAT_R8_UNORM:
 		case VK_FORMAT_A8B8G8R8_UNORM_PACK32:
 		case VK_FORMAT_A8B8G8R8_SRGB_PACK32:
 		case VK_FORMAT_A2B10G10R10_UNORM_PACK32:
 		case VK_FORMAT_A2R10G10B10_UNORM_PACK32:
 			for(unsigned int q : samples)
 			{
 				Pointer<Byte> buffer = cBuffer[index] + q * *Pointer<Int>(data + OFFSET(DrawData, colorSliceB[index]));

 				SIMD::Float4 colorf = alphaBlend(index, buffer, c[index], x);

 				ASSERT(SIMD::Width == 4);
 				Vector4s color;
 				color.x = UShort4(Extract128(colorf.x, 0) * 0xFFFF, true);  // Saturating
 				color.y = UShort4(Extract128(colorf.y, 0) * 0xFFFF, true);  // Saturating
 				color.z = UShort4(Extract128(colorf.z, 0) * 0xFFFF, true);  // Saturating
 				color.w = UShort4(Extract128(colorf.w, 0) * 0xFFFF, true);  // Saturating
 				writeColor(index, buffer, x, color, sMask[q], zMask[q], cMask[q]);
 			}
 			break;
 		case VK_FORMAT_R16_SFLOAT:
 		case VK_FORMAT_R16G16_SFLOAT:
 		case VK_FORMAT_R16G16B16A16_SFLOAT:
 		case VK_FORMAT_B10G11R11_UFLOAT_PACK32:
 		case VK_FORMAT_R32_SFLOAT:
 		case VK_FORMAT_R32G32_SFLOAT:
 		case VK_FORMAT_R32G32B32A32_SFLOAT:
 		case VK_FORMAT_R32_SINT:
 		case VK_FORMAT_R32G32_SINT:
 		case VK_FORMAT_R32G32B32A32_SINT:
 		case VK_FORMAT_R32_UINT:
 		case VK_FORMAT_R32G32_UINT:
 		case VK_FORMAT_R32G32B32A32_UINT:
 		case VK_FORMAT_R16_UNORM:
 		case VK_FORMAT_R16G16_UNORM:
 		case VK_FORMAT_R16G16B16A16_UNORM:
 		case VK_FORMAT_R16_SINT:
 		case VK_FORMAT_R16G16_SINT:
 		case VK_FORMAT_R16G16B16A16_SINT:
 		case VK_FORMAT_R16_UINT:
 		case VK_FORMAT_R16G16_UINT:
 		case VK_FORMAT_R16G16B16A16_UINT:
 		case VK_FORMAT_R8_SINT:
 		case VK_FORMAT_R8G8_SINT:
 		case VK_FORMAT_R8G8B8A8_SINT:
 		case VK_FORMAT_R8_UINT:
 		case VK_FORMAT_R8G8_UINT:
 		case VK_FORMAT_R8G8B8A8_UINT:
 		case VK_FORMAT_A8B8G8R8_UINT_PACK32:
 		case VK_FORMAT_A8B8G8R8_SINT_PACK32:
 		case VK_FORMAT_A2B10G10R10_UINT_PACK32:
 		case VK_FORMAT_A2R10G10B10_UINT_PACK32:
 			for(unsigned int q : samples)
 			{
 				Pointer<Byte> buffer = cBuffer[index] + q * *Pointer<Int>(data + OFFSET(DrawData, colorSliceB[index]));

 				SIMD::Float4 C = alphaBlend(index, buffer, c[index], x);
 				ASSERT(SIMD::Width == 4);
 				Vector4f color;
 				color.x = Extract128(C.x, 0);
 				color.y = Extract128(C.y, 0);
 				color.z = Extract128(C.z, 0);
 				color.w = Extract128(C.w, 0);
 				writeColor(index, buffer, x, color, sMask[q], zMask[q], cMask[q]);
 			}
 			break;
 		default:
 			UNSUPPORTED("VkFormat: %d", int(format));
 		}
 	}
 }

 void PixelProgram::clampColor(SIMD::Float4 color[MAX_COLOR_BUFFERS])
 {
 	// "If the color attachment is fixed-point, the components of the source and destination values and blend factors
 	//  are each clamped to [0,1] or [-1,1] respectively for an unsigned normalized or signed normalized color attachment
 	//  prior to evaluating the blend operations. If the color attachment is floating-point, no clamping occurs."

 	for(int index = 0; index < MAX_COLOR_BUFFERS; index++)
 	{
 		if(!state.colorWriteActive(index) && !(index == 0 && state.alphaToCoverage))
 		{
 			continue;
 		}

 		switch(state.colorFormat[index])
 		{
 		case VK_FORMAT_UNDEFINED:
 			break;
 		case VK_FORMAT_R4G4B4A4_UNORM_PACK16:
 		case VK_FORMAT_B4G4R4A4_UNORM_PACK16:
 		case VK_FORMAT_A4R4G4B4_UNORM_PACK16:
 		case VK_FORMAT_A4B4G4R4_UNORM_PACK16:
 		case VK_FORMAT_B5G6R5_UNORM_PACK16:
 		case VK_FORMAT_R5G5B5A1_UNORM_PACK16:
 		case VK_FORMAT_B5G5R5A1_UNORM_PACK16:
 		case VK_FORMAT_A1R5G5B5_UNORM_PACK16:
 		case VK_FORMAT_R5G6B5_UNORM_PACK16:
 		case VK_FORMAT_B8G8R8A8_UNORM:
 		case VK_FORMAT_B8G8R8A8_SRGB:
 		case VK_FORMAT_R8G8B8A8_UNORM:
 		case VK_FORMAT_R8G8B8A8_SRGB:
 		case VK_FORMAT_R8G8_UNORM:
 		case VK_FORMAT_R8_UNORM:
 		case VK_FORMAT_R16_UNORM:
 		case VK_FORMAT_R16G16_UNORM:
 		case VK_FORMAT_R16G16B16A16_UNORM:
 		case VK_FORMAT_A8B8G8R8_UNORM_PACK32:
 		case VK_FORMAT_A8B8G8R8_SRGB_PACK32:
 		case VK_FORMAT_A2B10G10R10_UNORM_PACK32:
 		case VK_FORMAT_A2R10G10B10_UNORM_PACK32:
 			color[index].x = Min(Max(color[index].x, 0.0f), 1.0f);
 			color[index].y = Min(Max(color[index].y, 0.0f), 1.0f);
 			color[index].z = Min(Max(color[index].z, 0.0f), 1.0f);
 			color[index].w = Min(Max(color[index].w, 0.0f), 1.0f);
 			break;
 		case VK_FORMAT_R32_SFLOAT:
 		case VK_FORMAT_R32G32_SFLOAT:
 		case VK_FORMAT_R32G32B32A32_SFLOAT:
 		case VK_FORMAT_R32_SINT:
 		case VK_FORMAT_R32G32_SINT:
 		case VK_FORMAT_R32G32B32A32_SINT:
 		case VK_FORMAT_R32_UINT:
 		case VK_FORMAT_R32G32_UINT:
 		case VK_FORMAT_R32G32B32A32_UINT:
 		case VK_FORMAT_R16_SFLOAT:
 		case VK_FORMAT_R16G16_SFLOAT:
 		case VK_FORMAT_R16G16B16A16_SFLOAT:
 		case VK_FORMAT_B10G11R11_UFLOAT_PACK32:
 		case VK_FORMAT_R16_SINT:
 		case VK_FORMAT_R16G16_SINT:
 		case VK_FORMAT_R16G16B16A16_SINT:
 		case VK_FORMAT_R16_UINT:
 		case VK_FORMAT_R16G16_UINT:
 		case VK_FORMAT_R16G16B16A16_UINT:
 		case VK_FORMAT_R8_SINT:
 		case VK_FORMAT_R8G8_SINT:
 		case VK_FORMAT_R8G8B8A8_SINT:
 		case VK_FORMAT_R8_UINT:
 		case VK_FORMAT_R8G8_UINT:
 		case VK_FORMAT_R8G8B8A8_UINT:
 		case VK_FORMAT_A8B8G8R8_UINT_PACK32:
 		case VK_FORMAT_A8B8G8R8_SINT_PACK32:
 		case VK_FORMAT_A2B10G10R10_UINT_PACK32:
 		case VK_FORMAT_A2R10G10B10_UINT_PACK32:
 			break;
 		default:
 			UNSUPPORTED("VkFormat: %d", int(state.colorFormat[index]));
 		}
 	}
 }

 }  // namespace sw
	// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	#include "PixelProgram.hpp"

	#include "Constants.hpp"
	#include "SamplerCore.hpp"
	#include "Device/Primitive.hpp"
	#include "Device/Renderer.hpp"
	#include "Vulkan/VkDevice.hpp"

	namespace sw {

	PixelProgram::PixelProgram(
	const PixelProcessor::State &state,
	const vk::PipelineLayout *pipelineLayout,
	const SpirvShader *spirvShader,
	const vk::DescriptorSet::Bindings &descriptorSets)
	: PixelRoutine(state, pipelineLayout, spirvShader, descriptorSets)
	{
	}

	// Union all cMask and return it as Booleans
	SIMD::Int PixelProgram::maskAny(Int cMask[4], const SampleSet &samples)
	{
	// See if at least 1 sample is used
	Int maskUnion = 0;
	for(unsigned int q : samples)
	{
	maskUnion \|= cMask[q];
	}

	// Convert to Booleans
	SIMD::Int laneBits = SIMD::Int([](int i) { return 1 << i; }); // 1, 2, 4, 8, ...
	SIMD::Int mask(maskUnion);
	mask = CmpNEQ(mask & laneBits, 0);
	return mask;
	}

	// Union all cMask/sMask/zMask and return it as Booleans
	SIMD::Int PixelProgram::maskAny(Int cMask[4], Int sMask[4], Int zMask[4], const SampleSet &samples)
	{
	// See if at least 1 sample is used
	Int maskUnion = 0;
	for(unsigned int q : samples)
	{
	maskUnion \|= (cMask[q] & sMask[q] & zMask[q]);
	}

	// Convert to Booleans
	SIMD::Int laneBits = SIMD::Int([](int i) { return 1 << i; }); // 1, 2, 4, 8, ...
	SIMD::Int mask(maskUnion);
	mask = CmpNEQ(mask & laneBits, 0);
	return mask;
	}

	void PixelProgram::setBuiltins(Int &x, Int &y, SIMD::Float (&z)[4], SIMD::Float &w, Int cMask[4], const SampleSet &samples)
	{
	routine.setImmutableInputBuiltins(spirvShader);

	// TODO(b/146486064): Consider only assigning these to the SpirvRoutine iff
	// they are ever going to be read.
	float x0 = 0.5f;
	float y0 = 0.5f;
	float x1 = 1.5f;
	float y1 = 1.5f;

	// "When Sample Shading is enabled, the x and y components of FragCoord reflect the
	// location of one of the samples corresponding to the shader invocation. Otherwise,
	// the x and y components of FragCoord reflect the location of the center of the fragment."
	if(state.sampleShadingEnabled && state.multiSampleCount > 1)
	{
	x0 = VkSampleLocations4[samples[0]][0];
	y0 = VkSampleLocations4[samples[0]][1];
	x1 = 1.0f + x0;
	y1 = 1.0f + y0;
	}

	routine.fragCoord[0] = SIMD::Float(Float(x)) + SIMD::Float(x0, x1, x0, x1);
	routine.fragCoord[1] = SIMD::Float(Float(y)) + SIMD::Float(y0, y0, y1, y1);
	routine.fragCoord[2] = z[0]; // sample 0
	routine.fragCoord[3] = w;

	routine.invocationsPerSubgroup = SIMD::Width;
	routine.helperInvocation = ~maskAny(cMask, samples);
	routine.windowSpacePosition[0] = SIMD::Int(x) + SIMD::Int(0, 1, 0, 1);
	routine.windowSpacePosition[1] = SIMD::Int(y) + SIMD::Int(0, 0, 1, 1);
	routine.layer = *Pointer<Int>(data + OFFSET(DrawData, layer));

	// 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)));
	routine.pointCoord[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, x0)))));
	routine.pointCoord[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, y0)))));

	routine.setInputBuiltin(spirvShader, spv::BuiltInViewIndex, [&](const SpirvShader::BuiltinMapping &builtin, Array<SIMD::Float> &value) {
	assert(builtin.SizeInComponents == 1);
	value[builtin.FirstComponent] = As<SIMD::Float>(SIMD::Int(routine.layer));
	});

	routine.setInputBuiltin(spirvShader, spv::BuiltInFragCoord, [&](const SpirvShader::BuiltinMapping &builtin, Array<SIMD::Float> &value) {
	assert(builtin.SizeInComponents == 4);
	value[builtin.FirstComponent + 0] = routine.fragCoord[0];
	value[builtin.FirstComponent + 1] = routine.fragCoord[1];
	value[builtin.FirstComponent + 2] = routine.fragCoord[2];
	value[builtin.FirstComponent + 3] = routine.fragCoord[3];
	});

	routine.setInputBuiltin(spirvShader, spv::BuiltInPointCoord, [&](const SpirvShader::BuiltinMapping &builtin, Array<SIMD::Float> &value) {
	assert(builtin.SizeInComponents == 2);
	value[builtin.FirstComponent + 0] = routine.pointCoord[0];
	value[builtin.FirstComponent + 1] = routine.pointCoord[1];
	});

	routine.setInputBuiltin(spirvShader, spv::BuiltInSubgroupSize, [&](const SpirvShader::BuiltinMapping &builtin, Array<SIMD::Float> &value) {
	assert(builtin.SizeInComponents == 1);
	value[builtin.FirstComponent] = As<SIMD::Float>(SIMD::Int(SIMD::Width));
	});

	routine.setInputBuiltin(spirvShader, spv::BuiltInHelperInvocation, [&](const SpirvShader::BuiltinMapping &builtin, Array<SIMD::Float> &value) {
	assert(builtin.SizeInComponents == 1);
	value[builtin.FirstComponent] = As<SIMD::Float>(routine.helperInvocation);
	});
	}

	void PixelProgram::executeShader(Int cMask[4], Int sMask[4], Int zMask[4], const SampleSet &samples)
	{
	routine.device = device;
	routine.descriptorSets = data + OFFSET(DrawData, descriptorSets);
	routine.descriptorDynamicOffsets = data + OFFSET(DrawData, descriptorDynamicOffsets);
	routine.pushConstants = data + OFFSET(DrawData, pushConstants);
	routine.constants = device + OFFSET(vk::Device, constants);

	auto it = spirvShader->inputBuiltins.find(spv::BuiltInFrontFacing);
	if(it != spirvShader->inputBuiltins.end())
	{
	ASSERT(it->second.SizeInComponents == 1);
	auto frontFacing = SIMD::Int(*Pointer<Int>(primitive + OFFSET(Primitive, clockwiseMask)));
	routine.getVariable(it->second.Id)[it->second.FirstComponent] = As<SIMD::Float>(frontFacing);
	}

	it = spirvShader->inputBuiltins.find(spv::BuiltInSampleMask);
	if(it != spirvShader->inputBuiltins.end())
	{
	ASSERT(SIMD::Width == 4);
	SIMD::Int laneBits = SIMD::Int(1, 2, 4, 8);

	SIMD::Int inputSampleMask = 0;
	for(unsigned int q : samples)
	{
	inputSampleMask \|= SIMD::Int(1 << q) & CmpNEQ(SIMD::Int(cMask[q]) & laneBits, 0);
	}

	routine.getVariable(it->second.Id)[it->second.FirstComponent] = As<SIMD::Float>(inputSampleMask);
	// Sample mask input is an array, as the spec contemplates MSAA levels higher than 32.
	// Fill any non-zero indices with 0.
	for(auto i = 1u; i < it->second.SizeInComponents; i++)
	{
	routine.getVariable(it->second.Id)[it->second.FirstComponent + i] = 0;
	}
	}

	it = spirvShader->inputBuiltins.find(spv::BuiltInSampleId);
	if(it != spirvShader->inputBuiltins.end())
	{
	ASSERT(samples.size() == 1);
	int sampleId = samples[0];
	routine.getVariable(it->second.Id)[it->second.FirstComponent] =
	As<SIMD::Float>(SIMD::Int(sampleId));
	}

	it = spirvShader->inputBuiltins.find(spv::BuiltInSamplePosition);
	if(it != spirvShader->inputBuiltins.end())
	{
	ASSERT(samples.size() == 1);
	int sampleId = samples[0];
	routine.getVariable(it->second.Id)[it->second.FirstComponent + 0] =
	SIMD::Float((state.multiSampleCount > 1) ? VkSampleLocations4[sampleId][0] : 0.5f);
	routine.getVariable(it->second.Id)[it->second.FirstComponent + 1] =
	SIMD::Float((state.multiSampleCount > 1) ? VkSampleLocations4[sampleId][1] : 0.5f);
	}

	// Note: all lanes initially active to facilitate derivatives etc. Actual coverage is
	// handled separately, through the cMask.
	SIMD::Int activeLaneMask = 0xFFFFFFFF;
	SIMD::Int storesAndAtomicsMask = maskAny(cMask, sMask, zMask, samples);
	routine.discardMask = 0;

	spirvShader->emit(&routine, activeLaneMask, storesAndAtomicsMask, descriptorSets, state.multiSampleCount);
	spirvShader->emitEpilog(&routine);
	// At the last invocation of the fragment shader, clear phi data.
	// TODO(b/178662288): Automatically clear phis through SpirvRoutine lifetime reduction.
	if(samples[0] == static_cast<int>(state.multiSampleCount - 1))
	{
	spirvShader->clearPhis(&routine);
	}

	for(int i = 0; i < MAX_COLOR_BUFFERS; i++)
	{
	c[i].x = routine.outputs[i * 4 + 0];
	c[i].y = routine.outputs[i * 4 + 1];
	c[i].z = routine.outputs[i * 4 + 2];
	c[i].w = routine.outputs[i * 4 + 3];
	}

	clampColor(c);

	if(spirvShader->getAnalysis().ContainsDiscard)
	{
	for(unsigned int q : samples)
	{
	cMask[q] &= ~routine.discardMask;
	}
	}

	it = spirvShader->outputBuiltins.find(spv::BuiltInSampleMask);
	if(it != spirvShader->outputBuiltins.end())
	{
	auto outputSampleMask = As<SIMD::Int>(routine.getVariable(it->second.Id)[it->second.FirstComponent]);

	for(unsigned int q : samples)
	{
	cMask[q] &= SignMask(CmpNEQ(outputSampleMask & SIMD::Int(1 << q), SIMD::Int(0)));
	}
	}

	it = spirvShader->outputBuiltins.find(spv::BuiltInFragDepth);
	if(it != spirvShader->outputBuiltins.end())
	{
	for(unsigned int q : samples)
	{
	z[q] = routine.getVariable(it->second.Id)[it->second.FirstComponent];
	}
	}
	}

	Bool PixelProgram::alphaTest(Int cMask[4], const SampleSet &samples)
	{
	if(!state.alphaToCoverage)
	{
	return true;
	}

	alphaToCoverage(cMask, c[0].w, samples);

	Int pass = 0;
	for(unsigned int q : samples)
	{
	pass = pass \| cMask[q];
	}

	return pass != 0x0;
	}

	void PixelProgram::blendColor(Pointer<Byte> cBuffer[4], Int &x, Int sMask[4], Int zMask[4], Int cMask[4], const SampleSet &samples)
	{
	for(int index = 0; index < MAX_COLOR_BUFFERS; index++)
	{
	if(!state.colorWriteActive(index))
	{
	continue;
	}

	auto format = state.colorFormat[index];
	switch(format)
	{
	case VK_FORMAT_R4G4B4A4_UNORM_PACK16:
	case VK_FORMAT_B4G4R4A4_UNORM_PACK16:
	case VK_FORMAT_A4R4G4B4_UNORM_PACK16:
	case VK_FORMAT_A4B4G4R4_UNORM_PACK16:
	case VK_FORMAT_B5G6R5_UNORM_PACK16:
	case VK_FORMAT_R5G5B5A1_UNORM_PACK16:
	case VK_FORMAT_B5G5R5A1_UNORM_PACK16:
	case VK_FORMAT_A1R5G5B5_UNORM_PACK16:
	case VK_FORMAT_R5G6B5_UNORM_PACK16:
	case VK_FORMAT_B8G8R8A8_UNORM:
	case VK_FORMAT_B8G8R8A8_SRGB:
	case VK_FORMAT_R8G8B8A8_UNORM:
	case VK_FORMAT_R8G8B8A8_SRGB:
	case VK_FORMAT_R8G8_UNORM:
	case VK_FORMAT_R8_UNORM:
	case VK_FORMAT_A8B8G8R8_UNORM_PACK32:
	case VK_FORMAT_A8B8G8R8_SRGB_PACK32:
	case VK_FORMAT_A2B10G10R10_UNORM_PACK32:
	case VK_FORMAT_A2R10G10B10_UNORM_PACK32:
	for(unsigned int q : samples)
	{
	Pointer<Byte> buffer = cBuffer[index] + q * *Pointer<Int>(data + OFFSET(DrawData, colorSliceB[index]));

	SIMD::Float4 colorf = alphaBlend(index, buffer, c[index], x);

	ASSERT(SIMD::Width == 4);
	Vector4s color;
	color.x = UShort4(Extract128(colorf.x, 0) * 0xFFFF, true); // Saturating
	color.y = UShort4(Extract128(colorf.y, 0) * 0xFFFF, true); // Saturating
	color.z = UShort4(Extract128(colorf.z, 0) * 0xFFFF, true); // Saturating
	color.w = UShort4(Extract128(colorf.w, 0) * 0xFFFF, true); // Saturating
	writeColor(index, buffer, x, color, sMask[q], zMask[q], cMask[q]);
	}
	break;
	case VK_FORMAT_R16_SFLOAT:
	case VK_FORMAT_R16G16_SFLOAT:
	case VK_FORMAT_R16G16B16A16_SFLOAT:
	case VK_FORMAT_B10G11R11_UFLOAT_PACK32:
	case VK_FORMAT_R32_SFLOAT:
	case VK_FORMAT_R32G32_SFLOAT:
	case VK_FORMAT_R32G32B32A32_SFLOAT:
	case VK_FORMAT_R32_SINT:
	case VK_FORMAT_R32G32_SINT:
	case VK_FORMAT_R32G32B32A32_SINT:
	case VK_FORMAT_R32_UINT:
	case VK_FORMAT_R32G32_UINT:
	case VK_FORMAT_R32G32B32A32_UINT:
	case VK_FORMAT_R16_UNORM:
	case VK_FORMAT_R16G16_UNORM:
	case VK_FORMAT_R16G16B16A16_UNORM:
	case VK_FORMAT_R16_SINT:
	case VK_FORMAT_R16G16_SINT:
	case VK_FORMAT_R16G16B16A16_SINT:
	case VK_FORMAT_R16_UINT:
	case VK_FORMAT_R16G16_UINT:
	case VK_FORMAT_R16G16B16A16_UINT:
	case VK_FORMAT_R8_SINT:
	case VK_FORMAT_R8G8_SINT:
	case VK_FORMAT_R8G8B8A8_SINT:
	case VK_FORMAT_R8_UINT:
	case VK_FORMAT_R8G8_UINT:
	case VK_FORMAT_R8G8B8A8_UINT:
	case VK_FORMAT_A8B8G8R8_UINT_PACK32:
	case VK_FORMAT_A8B8G8R8_SINT_PACK32:
	case VK_FORMAT_A2B10G10R10_UINT_PACK32:
	case VK_FORMAT_A2R10G10B10_UINT_PACK32:
	for(unsigned int q : samples)
	{
	Pointer<Byte> buffer = cBuffer[index] + q * *Pointer<Int>(data + OFFSET(DrawData, colorSliceB[index]));

	SIMD::Float4 C = alphaBlend(index, buffer, c[index], x);
	ASSERT(SIMD::Width == 4);
	Vector4f color;
	color.x = Extract128(C.x, 0);
	color.y = Extract128(C.y, 0);
	color.z = Extract128(C.z, 0);
	color.w = Extract128(C.w, 0);
	writeColor(index, buffer, x, color, sMask[q], zMask[q], cMask[q]);
	}
	break;
	default:
	UNSUPPORTED("VkFormat: %d", int(format));
	}
	}
	}

	void PixelProgram::clampColor(SIMD::Float4 color[MAX_COLOR_BUFFERS])
	{
	// "If the color attachment is fixed-point, the components of the source and destination values and blend factors
	// are each clamped to [0,1] or [-1,1] respectively for an unsigned normalized or signed normalized color attachment
	// prior to evaluating the blend operations. If the color attachment is floating-point, no clamping occurs."

	for(int index = 0; index < MAX_COLOR_BUFFERS; index++)
	{
	if(!state.colorWriteActive(index) && !(index == 0 && state.alphaToCoverage))
	{
	continue;
	}

	switch(state.colorFormat[index])
	{
	case VK_FORMAT_UNDEFINED:
	break;
	case VK_FORMAT_R4G4B4A4_UNORM_PACK16:
	case VK_FORMAT_B4G4R4A4_UNORM_PACK16:
	case VK_FORMAT_A4R4G4B4_UNORM_PACK16:
	case VK_FORMAT_A4B4G4R4_UNORM_PACK16:
	case VK_FORMAT_B5G6R5_UNORM_PACK16:
	case VK_FORMAT_R5G5B5A1_UNORM_PACK16:
	case VK_FORMAT_B5G5R5A1_UNORM_PACK16:
	case VK_FORMAT_A1R5G5B5_UNORM_PACK16:
	case VK_FORMAT_R5G6B5_UNORM_PACK16:
	case VK_FORMAT_B8G8R8A8_UNORM:
	case VK_FORMAT_B8G8R8A8_SRGB:
	case VK_FORMAT_R8G8B8A8_UNORM:
	case VK_FORMAT_R8G8B8A8_SRGB:
	case VK_FORMAT_R8G8_UNORM:
	case VK_FORMAT_R8_UNORM:
	case VK_FORMAT_R16_UNORM:
	case VK_FORMAT_R16G16_UNORM:
	case VK_FORMAT_R16G16B16A16_UNORM:
	case VK_FORMAT_A8B8G8R8_UNORM_PACK32:
	case VK_FORMAT_A8B8G8R8_SRGB_PACK32:
	case VK_FORMAT_A2B10G10R10_UNORM_PACK32:
	case VK_FORMAT_A2R10G10B10_UNORM_PACK32:
	color[index].x = Min(Max(color[index].x, 0.0f), 1.0f);
	color[index].y = Min(Max(color[index].y, 0.0f), 1.0f);
	color[index].z = Min(Max(color[index].z, 0.0f), 1.0f);
	color[index].w = Min(Max(color[index].w, 0.0f), 1.0f);
	break;
	case VK_FORMAT_R32_SFLOAT:
	case VK_FORMAT_R32G32_SFLOAT:
	case VK_FORMAT_R32G32B32A32_SFLOAT:
	case VK_FORMAT_R32_SINT:
	case VK_FORMAT_R32G32_SINT:
	case VK_FORMAT_R32G32B32A32_SINT:
	case VK_FORMAT_R32_UINT:
	case VK_FORMAT_R32G32_UINT:
	case VK_FORMAT_R32G32B32A32_UINT:
	case VK_FORMAT_R16_SFLOAT:
	case VK_FORMAT_R16G16_SFLOAT:
	case VK_FORMAT_R16G16B16A16_SFLOAT:
	case VK_FORMAT_B10G11R11_UFLOAT_PACK32:
	case VK_FORMAT_R16_SINT:
	case VK_FORMAT_R16G16_SINT:
	case VK_FORMAT_R16G16B16A16_SINT:
	case VK_FORMAT_R16_UINT:
	case VK_FORMAT_R16G16_UINT:
	case VK_FORMAT_R16G16B16A16_UINT:
	case VK_FORMAT_R8_SINT:
	case VK_FORMAT_R8G8_SINT:
	case VK_FORMAT_R8G8B8A8_SINT:
	case VK_FORMAT_R8_UINT:
	case VK_FORMAT_R8G8_UINT:
	case VK_FORMAT_R8G8B8A8_UINT:
	case VK_FORMAT_A8B8G8R8_UINT_PACK32:
	case VK_FORMAT_A8B8G8R8_SINT_PACK32:
	case VK_FORMAT_A2B10G10R10_UINT_PACK32:
	case VK_FORMAT_A2R10G10B10_UINT_PACK32:
	break;
	default:
	UNSUPPORTED("VkFormat: %d", int(state.colorFormat[index]));
	}
	}
	}

	} // namespace sw