// Copyright 2020 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 "Context.hpp"

#include "Vulkan/VkBuffer.hpp"
#include "Vulkan/VkDevice.hpp"
#include "Vulkan/VkImageView.hpp"
#include "Vulkan/VkRenderPass.hpp"
#include "Vulkan/VkStringify.hpp"

namespace {

uint32_t ComputePrimitiveCount(VkPrimitiveTopology topology, uint32_t vertexCount)
{
	switch(topology)
	{
	case VK_PRIMITIVE_TOPOLOGY_POINT_LIST:
		return vertexCount;
	case VK_PRIMITIVE_TOPOLOGY_LINE_LIST:
		return vertexCount / 2;
	case VK_PRIMITIVE_TOPOLOGY_LINE_STRIP:
		return std::max<uint32_t>(vertexCount, 1) - 1;
	case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST:
		return vertexCount / 3;
	case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP:
		return std::max<uint32_t>(vertexCount, 2) - 2;
	case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN:
		return std::max<uint32_t>(vertexCount, 2) - 2;
	default:
		UNSUPPORTED("VkPrimitiveTopology %d", int(topology));
	}

	return 0;
}

template<typename T>
void ProcessPrimitiveRestart(T *indexBuffer,
                             VkPrimitiveTopology topology,
                             uint32_t count,
                             std::vector<std::pair<uint32_t, void *>> *indexBuffers)
{
	static const T RestartIndex = static_cast<T>(-1);
	T *indexBufferStart = indexBuffer;
	uint32_t vertexCount = 0;
	for(uint32_t i = 0; i < count; i++)
	{
		if(indexBuffer[i] == RestartIndex)
		{
			// Record previous segment
			if(vertexCount > 0)
			{
				uint32_t primitiveCount = ComputePrimitiveCount(topology, vertexCount);
				if(primitiveCount > 0)
				{
					indexBuffers->push_back({ primitiveCount, indexBufferStart });
				}
			}
			vertexCount = 0;
		}
		else
		{
			if(vertexCount == 0)
			{
				indexBufferStart = indexBuffer + i;
			}
			vertexCount++;
		}
	}

	// Record last segment
	if(vertexCount > 0)
	{
		uint32_t primitiveCount = ComputePrimitiveCount(topology, vertexCount);
		if(primitiveCount > 0)
		{
			indexBuffers->push_back({ primitiveCount, indexBufferStart });
		}
	}
}

}  // namespace

namespace vk {

int IndexBuffer::bytesPerIndex() const
{
	return indexType == VK_INDEX_TYPE_UINT16 ? 2 : 4;
}

void IndexBuffer::setIndexBufferBinding(const VertexInputBinding &indexBufferBinding, VkIndexType type)
{
	binding = indexBufferBinding;
	indexType = type;
}

void IndexBuffer::getIndexBuffers(VkPrimitiveTopology topology, uint32_t count, uint32_t first, bool indexed, bool hasPrimitiveRestartEnable, std::vector<std::pair<uint32_t, void *>> *indexBuffers) const
{

	if(indexed)
	{
		void *indexBuffer = binding.buffer->getOffsetPointer(binding.offset + first * bytesPerIndex());
		if(hasPrimitiveRestartEnable)
		{
			switch(indexType)
			{
			case VK_INDEX_TYPE_UINT16:
				ProcessPrimitiveRestart(static_cast<uint16_t *>(indexBuffer), topology, count, indexBuffers);
				break;
			case VK_INDEX_TYPE_UINT32:
				ProcessPrimitiveRestart(static_cast<uint32_t *>(indexBuffer), topology, count, indexBuffers);
				break;
			default:
				UNSUPPORTED("VkIndexType %d", int(indexType));
			}
		}
		else
		{
			indexBuffers->push_back({ ComputePrimitiveCount(topology, count), indexBuffer });
		}
	}
	else
	{
		indexBuffers->push_back({ ComputePrimitiveCount(topology, count), nullptr });
	}
}

bool Attachments::isColorClamped(int index) const
{
	if(colorBuffer[index] && colorBuffer[index]->getFormat().isFloatFormat())
	{
		return false;
	}

	return true;
}

VkFormat Attachments::colorFormat(int index) const
{
	ASSERT((index >= 0) && (index < sw::MAX_COLOR_BUFFERS));

	if(colorBuffer[index])
	{
		return colorBuffer[index]->getFormat();
	}
	else
	{
		return VK_FORMAT_UNDEFINED;
	}
}

VkFormat Attachments::depthFormat() const
{
	if(depthBuffer)
	{
		return depthBuffer->getFormat();
	}
	else
	{
		return VK_FORMAT_UNDEFINED;
	}
}

Inputs::Inputs(const VkPipelineVertexInputStateCreateInfo *vertexInputState)
{
	if(vertexInputState->flags != 0)
	{
		// Vulkan 1.2: "flags is reserved for future use." "flags must be 0"
		UNSUPPORTED("vertexInputState->flags");
	}

	// Temporary in-binding-order representation of buffer strides, to be consumed below
	// when considering attributes. TODO: unfuse buffers from attributes in backend, is old GL model.
	uint32_t vertexStrides[MAX_VERTEX_INPUT_BINDINGS];
	uint32_t instanceStrides[MAX_VERTEX_INPUT_BINDINGS];
	for(uint32_t i = 0; i < vertexInputState->vertexBindingDescriptionCount; i++)
	{
		auto const &desc = vertexInputState->pVertexBindingDescriptions[i];
		vertexStrides[desc.binding] = desc.inputRate == VK_VERTEX_INPUT_RATE_VERTEX ? desc.stride : 0;
		instanceStrides[desc.binding] = desc.inputRate == VK_VERTEX_INPUT_RATE_INSTANCE ? desc.stride : 0;
	}

	for(uint32_t i = 0; i < vertexInputState->vertexAttributeDescriptionCount; i++)
	{
		auto const &desc = vertexInputState->pVertexAttributeDescriptions[i];
		sw::Stream &input = stream[desc.location];
		input.format = desc.format;
		input.offset = desc.offset;
		input.binding = desc.binding;
		input.vertexStride = vertexStrides[desc.binding];
		input.instanceStride = instanceStrides[desc.binding];
	}
}

void Inputs::updateDescriptorSets(const DescriptorSet::Array &dso,
                                  const DescriptorSet::Bindings &ds,
                                  const DescriptorSet::DynamicOffsets &ddo)
{
	descriptorSetObjects = dso;
	descriptorSets = ds;
	descriptorDynamicOffsets = ddo;
}

void Inputs::bindVertexInputs(int firstInstance)
{
	for(uint32_t i = 0; i < MAX_VERTEX_INPUT_BINDINGS; i++)
	{
		auto &attrib = stream[i];
		if(attrib.format != VK_FORMAT_UNDEFINED)
		{
			const auto &vertexInput = vertexInputBindings[attrib.binding];
			VkDeviceSize offset = attrib.offset + vertexInput.offset +
			                      attrib.instanceStride * firstInstance;
			attrib.buffer = vertexInput.buffer ? vertexInput.buffer->getOffsetPointer(offset) : nullptr;

			VkDeviceSize size = vertexInput.buffer ? vertexInput.buffer->getSize() : 0;
			attrib.robustnessSize = (size > offset) ? size - offset : 0;
		}
	}
}

void Inputs::setVertexInputBinding(const VertexInputBinding bindings[])
{
	for(uint32_t i = 0; i < MAX_VERTEX_INPUT_BINDINGS; ++i)
	{
		vertexInputBindings[i] = bindings[i];
	}
}

// TODO(b/137740918): Optimize instancing to use a single draw call.
void Inputs::advanceInstanceAttributes()
{
	for(uint32_t i = 0; i < vk::MAX_VERTEX_INPUT_BINDINGS; i++)
	{
		auto &attrib = stream[i];
		if((attrib.format != VK_FORMAT_UNDEFINED) && attrib.instanceStride && (attrib.instanceStride < attrib.robustnessSize))
		{
			// Under the casts: attrib.buffer += attrib.instanceStride
			attrib.buffer = (void const *)((uintptr_t)attrib.buffer + attrib.instanceStride);
			attrib.robustnessSize -= attrib.instanceStride;
		}
	}
}

GraphicsState::GraphicsState(const Device *device, const VkGraphicsPipelineCreateInfo *pCreateInfo,
                             const PipelineLayout *layout, bool robustBufferAccess)
    : pipelineLayout(layout)
    , robustBufferAccess(robustBufferAccess)
{
	if((pCreateInfo->flags &
	    ~(VK_PIPELINE_CREATE_DISABLE_OPTIMIZATION_BIT |
	      VK_PIPELINE_CREATE_DERIVATIVE_BIT |
	      VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BIT)) != 0)
	{
		UNSUPPORTED("pCreateInfo->flags %d", int(pCreateInfo->flags));
	}

	if(pCreateInfo->pDynamicState)
	{
		if(pCreateInfo->pDynamicState->flags != 0)
		{
			// Vulkan 1.2: "flags is reserved for future use." "flags must be 0"
			UNSUPPORTED("pCreateInfo->pDynamicState->flags %d", int(pCreateInfo->pDynamicState->flags));
		}

		for(uint32_t i = 0; i < pCreateInfo->pDynamicState->dynamicStateCount; i++)
		{
			VkDynamicState dynamicState = pCreateInfo->pDynamicState->pDynamicStates[i];
			switch(dynamicState)
			{
			case VK_DYNAMIC_STATE_VIEWPORT:
			case VK_DYNAMIC_STATE_SCISSOR:
			case VK_DYNAMIC_STATE_LINE_WIDTH:
			case VK_DYNAMIC_STATE_DEPTH_BIAS:
			case VK_DYNAMIC_STATE_BLEND_CONSTANTS:
			case VK_DYNAMIC_STATE_DEPTH_BOUNDS:
			case VK_DYNAMIC_STATE_STENCIL_COMPARE_MASK:
			case VK_DYNAMIC_STATE_STENCIL_WRITE_MASK:
			case VK_DYNAMIC_STATE_STENCIL_REFERENCE:
				ASSERT(dynamicState < (sizeof(dynamicStateFlags) * 8));
				dynamicStateFlags |= (1 << dynamicState);
				break;
			default:
				UNSUPPORTED("VkDynamicState %d", int(dynamicState));
			}
		}
	}

	const VkPipelineVertexInputStateCreateInfo *vertexInputState = pCreateInfo->pVertexInputState;

	if(vertexInputState->flags != 0)
	{
		// Vulkan 1.2: "flags is reserved for future use." "flags must be 0"
		UNSUPPORTED("vertexInputState->flags");
	}

	const VkPipelineInputAssemblyStateCreateInfo *inputAssemblyState = pCreateInfo->pInputAssemblyState;

	if(inputAssemblyState->flags != 0)
	{
		// Vulkan 1.2: "flags is reserved for future use." "flags must be 0"
		UNSUPPORTED("pCreateInfo->pInputAssemblyState->flags %d", int(pCreateInfo->pInputAssemblyState->flags));
	}

	primitiveRestartEnable = (inputAssemblyState->primitiveRestartEnable != VK_FALSE);
	topology = inputAssemblyState->topology;

	const VkPipelineRasterizationStateCreateInfo *rasterizationState = pCreateInfo->pRasterizationState;

	if(rasterizationState->flags != 0)
	{
		// Vulkan 1.2: "flags is reserved for future use." "flags must be 0"
		UNSUPPORTED("pCreateInfo->pRasterizationState->flags %d", int(pCreateInfo->pRasterizationState->flags));
	}

	rasterizerDiscard = (rasterizationState->rasterizerDiscardEnable != VK_FALSE);
	cullMode = rasterizationState->cullMode;
	frontFace = rasterizationState->frontFace;
	polygonMode = rasterizationState->polygonMode;
	constantDepthBias = (rasterizationState->depthBiasEnable != VK_FALSE) ? rasterizationState->depthBiasConstantFactor : 0.0f;
	slopeDepthBias = (rasterizationState->depthBiasEnable != VK_FALSE) ? rasterizationState->depthBiasSlopeFactor : 0.0f;
	depthBiasClamp = (rasterizationState->depthBiasEnable != VK_FALSE) ? rasterizationState->depthBiasClamp : 0.0f;
	depthRangeUnrestricted = device->hasExtension(VK_EXT_DEPTH_RANGE_UNRESTRICTED_EXTENSION_NAME);
	depthClampEnable = rasterizationState->depthClampEnable != VK_FALSE;
	depthClipEnable = !depthClampEnable;

	// From the Vulkan spec for vkCmdSetDepthBias:
	//    The bias value O for a polygon is:
	//        O = dbclamp(...)
	//    where dbclamp(x) =
	//        * x                       depthBiasClamp = 0 or NaN
	//        * min(x, depthBiasClamp)  depthBiasClamp > 0
	//        * max(x, depthBiasClamp)  depthBiasClamp < 0
	// So it should be safe to resolve NaNs to 0.0f.
	if(std::isnan(depthBiasClamp))
	{
		depthBiasClamp = 0.0f;
	}

	lineWidth = rasterizationState->lineWidth;

	const VkBaseInStructure *extensionCreateInfo = reinterpret_cast<const VkBaseInStructure *>(rasterizationState->pNext);
	while(extensionCreateInfo)
	{
		// Casting to a long since some structures, such as
		// VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROVOKING_VERTEX_FEATURES_EXT
		// are not enumerated in the official Vulkan header
		switch((long)(extensionCreateInfo->sType))
		{
		case VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_LINE_STATE_CREATE_INFO_EXT:
			{
				const VkPipelineRasterizationLineStateCreateInfoEXT *lineStateCreateInfo = reinterpret_cast<const VkPipelineRasterizationLineStateCreateInfoEXT *>(extensionCreateInfo);
				lineRasterizationMode = lineStateCreateInfo->lineRasterizationMode;
			}
			break;
		case VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_PROVOKING_VERTEX_STATE_CREATE_INFO_EXT:
			{
				const VkPipelineRasterizationProvokingVertexStateCreateInfoEXT *provokingVertexModeCreateInfo =
				    reinterpret_cast<const VkPipelineRasterizationProvokingVertexStateCreateInfoEXT *>(extensionCreateInfo);
				provokingVertexMode = provokingVertexModeCreateInfo->provokingVertexMode;
			}
			break;
		case VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_DEPTH_CLIP_STATE_CREATE_INFO_EXT:
			{
				const auto *depthClipInfo = reinterpret_cast<const VkPipelineRasterizationDepthClipStateCreateInfoEXT *>(extensionCreateInfo);
				// Reserved for future use.
				ASSERT(depthClipInfo->flags == 0);
				depthClipEnable = depthClipInfo->depthClipEnable != VK_FALSE;
			}
			break;
		default:
			WARN("pCreateInfo->pRasterizationState->pNext sType = %s", vk::Stringify(extensionCreateInfo->sType).c_str());
			break;
		}

		extensionCreateInfo = extensionCreateInfo->pNext;
	}

	// The sample count affects the batch size, so it needs initialization even if rasterization is disabled.
	// TODO(b/147812380): Eliminate the dependency between multisampling and batch size.
	sampleCount = 1;

	// Only access rasterization state if rasterization is not disabled.
	if(rasterizationState->rasterizerDiscardEnable == VK_FALSE)
	{
		const VkPipelineViewportStateCreateInfo *viewportState = pCreateInfo->pViewportState;
		const VkPipelineMultisampleStateCreateInfo *multisampleState = pCreateInfo->pMultisampleState;
		const VkPipelineDepthStencilStateCreateInfo *depthStencilState = pCreateInfo->pDepthStencilState;
		const VkPipelineColorBlendStateCreateInfo *colorBlendState = pCreateInfo->pColorBlendState;

		if(viewportState->flags != 0)
		{
			// Vulkan 1.2: "flags is reserved for future use." "flags must be 0"
			UNSUPPORTED("pCreateInfo->pViewportState->flags %d", int(pCreateInfo->pViewportState->flags));
		}

		if((viewportState->viewportCount != 1) ||
		   (viewportState->scissorCount != 1))
		{
			UNSUPPORTED("VkPhysicalDeviceFeatures::multiViewport");
		}

		if(!hasDynamicState(VK_DYNAMIC_STATE_SCISSOR))
		{
			scissor = viewportState->pScissors[0];
		}

		if(!hasDynamicState(VK_DYNAMIC_STATE_VIEWPORT))
		{
			viewport = viewportState->pViewports[0];
		}

		if(multisampleState->flags != 0)
		{
			// Vulkan 1.2: "flags is reserved for future use." "flags must be 0"
			UNSUPPORTED("pCreateInfo->pMultisampleState->flags %d", int(pCreateInfo->pMultisampleState->flags));
		}

		sampleShadingEnable = (multisampleState->sampleShadingEnable != VK_FALSE);
		if(sampleShadingEnable)
		{
			minSampleShading = multisampleState->minSampleShading;
		}

		if(multisampleState->alphaToOneEnable != VK_FALSE)
		{
			UNSUPPORTED("VkPhysicalDeviceFeatures::alphaToOne");
		}

		switch(multisampleState->rasterizationSamples)
		{
		case VK_SAMPLE_COUNT_1_BIT:
			sampleCount = 1;
			break;
		case VK_SAMPLE_COUNT_4_BIT:
			sampleCount = 4;
			break;
		default:
			UNSUPPORTED("Unsupported sample count");
		}

		VkSampleMask sampleMask;
		if(multisampleState->pSampleMask)
		{
			sampleMask = multisampleState->pSampleMask[0];
		}
		else  // "If pSampleMask is NULL, it is treated as if the mask has all bits set to 1."
		{
			sampleMask = ~0;
		}

		alphaToCoverage = (multisampleState->alphaToCoverageEnable != VK_FALSE);
		multiSampleMask = sampleMask & ((unsigned)0xFFFFFFFF >> (32 - sampleCount));

		const vk::RenderPass *renderPass = vk::Cast(pCreateInfo->renderPass);
		const VkSubpassDescription &subpass = renderPass->getSubpass(pCreateInfo->subpass);

		// Ignore pDepthStencilState when "the subpass of the render pass the pipeline is created against does not use a depth/stencil attachment"
		if(subpass.pDepthStencilAttachment && subpass.pDepthStencilAttachment->attachment != VK_ATTACHMENT_UNUSED)
		{
			if(depthStencilState->flags != 0)
			{
				// Vulkan 1.2: "flags is reserved for future use." "flags must be 0"
				UNSUPPORTED("pCreateInfo->pDepthStencilState->flags %d", int(pCreateInfo->pDepthStencilState->flags));
			}

			depthBoundsTestEnable = (depthStencilState->depthBoundsTestEnable != VK_FALSE);
			minDepthBounds = depthStencilState->minDepthBounds;
			maxDepthBounds = depthStencilState->maxDepthBounds;

			depthTestEnable = (depthStencilState->depthTestEnable != VK_FALSE);
			depthWriteEnable = (depthStencilState->depthWriteEnable != VK_FALSE);
			depthCompareMode = depthStencilState->depthCompareOp;

			stencilEnable = (depthStencilState->stencilTestEnable != VK_FALSE);
			if(stencilEnable)
			{
				frontStencil = depthStencilState->front;
				backStencil = depthStencilState->back;
			}
		}

		bool colorAttachmentUsed = false;
		for(uint32_t i = 0; i < subpass.colorAttachmentCount; i++)
		{
			if(subpass.pColorAttachments[i].attachment != VK_ATTACHMENT_UNUSED)
			{
				colorAttachmentUsed = true;
				break;
			}
		}

		// Ignore pColorBlendState when "the subpass of the render pass the pipeline is created against does not use any color attachments"
		if(colorAttachmentUsed)
		{
			if(colorBlendState->flags != 0)
			{
				// Vulkan 1.2: "flags is reserved for future use." "flags must be 0"
				UNSUPPORTED("pCreateInfo->pColorBlendState->flags %d", int(pCreateInfo->pColorBlendState->flags));
			}

			if(colorBlendState->logicOpEnable != VK_FALSE)
			{
				UNSUPPORTED("VkPhysicalDeviceFeatures::logicOp");
			}

			if(!hasDynamicState(VK_DYNAMIC_STATE_BLEND_CONSTANTS))
			{
				blendConstants.x = colorBlendState->blendConstants[0];
				blendConstants.y = colorBlendState->blendConstants[1];
				blendConstants.z = colorBlendState->blendConstants[2];
				blendConstants.w = colorBlendState->blendConstants[3];
			}

			ASSERT(colorBlendState->attachmentCount <= sw::MAX_COLOR_BUFFERS);
			for(auto i = 0u; i < colorBlendState->attachmentCount; i++)
			{
				const VkPipelineColorBlendAttachmentState &attachment = colorBlendState->pAttachments[i];
				colorWriteMask[i] = attachment.colorWriteMask;
				blendState[i] = { (attachment.blendEnable != VK_FALSE),
					              attachment.srcColorBlendFactor, attachment.dstColorBlendFactor, attachment.colorBlendOp,
					              attachment.srcAlphaBlendFactor, attachment.dstAlphaBlendFactor, attachment.alphaBlendOp };
			}
		}
	}
}

bool GraphicsState::isDrawPoint(bool polygonModeAware) const
{
	switch(topology)
	{
	case VK_PRIMITIVE_TOPOLOGY_POINT_LIST:
		return true;
	case VK_PRIMITIVE_TOPOLOGY_LINE_LIST:
	case VK_PRIMITIVE_TOPOLOGY_LINE_STRIP:
		return false;
	case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST:
	case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP:
	case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN:
		return polygonModeAware ? (polygonMode == VK_POLYGON_MODE_POINT) : false;
	default:
		UNSUPPORTED("topology %d", int(topology));
	}
	return false;
}

bool GraphicsState::isDrawLine(bool polygonModeAware) const
{
	switch(topology)
	{
	case VK_PRIMITIVE_TOPOLOGY_POINT_LIST:
		return false;
	case VK_PRIMITIVE_TOPOLOGY_LINE_LIST:
	case VK_PRIMITIVE_TOPOLOGY_LINE_STRIP:
		return true;
	case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST:
	case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP:
	case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN:
		return polygonModeAware ? (polygonMode == VK_POLYGON_MODE_LINE) : false;
	default:
		UNSUPPORTED("topology %d", int(topology));
	}
	return false;
}

bool GraphicsState::isDrawTriangle(bool polygonModeAware) const
{
	switch(topology)
	{
	case VK_PRIMITIVE_TOPOLOGY_POINT_LIST:
	case VK_PRIMITIVE_TOPOLOGY_LINE_LIST:
	case VK_PRIMITIVE_TOPOLOGY_LINE_STRIP:
		return false;
	case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST:
	case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP:
	case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN:
		return polygonModeAware ? (polygonMode == VK_POLYGON_MODE_FILL) : true;
	default:
		UNSUPPORTED("topology %d", int(topology));
	}
	return false;
}

bool GraphicsState::depthWriteActive(const Attachments &attachments) const
{
	// "Depth writes are always disabled when depthTestEnable is VK_FALSE."
	return depthTestActive(attachments) && depthWriteEnable;
}

bool GraphicsState::depthTestActive(const Attachments &attachments) const
{
	return attachments.depthBuffer && depthTestEnable;
}

bool GraphicsState::stencilActive(const Attachments &attachments) const
{
	return attachments.stencilBuffer && stencilEnable;
}

bool GraphicsState::depthBoundsTestActive(const Attachments &attachments) const
{
	return attachments.depthBuffer && depthBoundsTestEnable;
}

const GraphicsState GraphicsState::combineStates(const DynamicState &dynamicState) const
{
	GraphicsState combinedState = *this;

	// Apply either pipeline state or dynamic state
	if(hasDynamicState(VK_DYNAMIC_STATE_SCISSOR))
	{
		combinedState.scissor = dynamicState.scissor;
	}

	if(hasDynamicState(VK_DYNAMIC_STATE_VIEWPORT))
	{
		combinedState.viewport = dynamicState.viewport;
	}

	if(hasDynamicState(VK_DYNAMIC_STATE_BLEND_CONSTANTS))
	{
		combinedState.blendConstants = dynamicState.blendConstants;
	}

	if(hasDynamicState(VK_DYNAMIC_STATE_DEPTH_BIAS))
	{
		combinedState.constantDepthBias = dynamicState.depthBiasConstantFactor;
		combinedState.slopeDepthBias = dynamicState.depthBiasSlopeFactor;
		combinedState.depthBiasClamp = dynamicState.depthBiasClamp;
	}

	if(hasDynamicState(VK_DYNAMIC_STATE_DEPTH_BOUNDS) && depthBoundsTestEnable)
	{
		combinedState.minDepthBounds = dynamicState.minDepthBounds;
		combinedState.maxDepthBounds = dynamicState.maxDepthBounds;
	}

	if(hasDynamicState(VK_DYNAMIC_STATE_STENCIL_COMPARE_MASK) && stencilEnable)
	{
		combinedState.frontStencil.compareMask = dynamicState.compareMask[0];
		combinedState.backStencil.compareMask = dynamicState.compareMask[1];
	}

	if(hasDynamicState(VK_DYNAMIC_STATE_STENCIL_WRITE_MASK) && stencilEnable)
	{
		combinedState.frontStencil.writeMask = dynamicState.writeMask[0];
		combinedState.backStencil.writeMask = dynamicState.writeMask[1];
	}

	if(hasDynamicState(VK_DYNAMIC_STATE_STENCIL_REFERENCE) && stencilEnable)
	{
		combinedState.frontStencil.reference = dynamicState.reference[0];
		combinedState.backStencil.reference = dynamicState.reference[1];
	}

	return combinedState;
}

BlendState GraphicsState::getBlendState(int index, const Attachments &attachments, bool fragmentContainsKill) const
{
	ASSERT((index >= 0) && (index < sw::MAX_COLOR_BUFFERS));

	BlendState activeBlendState;
	activeBlendState.alphaBlendEnable = alphaBlendActive(index, attachments, fragmentContainsKill);
	activeBlendState.sourceBlendFactor = sourceBlendFactor(index);
	activeBlendState.destBlendFactor = destBlendFactor(index);
	activeBlendState.blendOperation = blendOperation(index, attachments);
	activeBlendState.sourceBlendFactorAlpha = sourceBlendFactorAlpha(index);
	activeBlendState.destBlendFactorAlpha = destBlendFactorAlpha(index);
	activeBlendState.blendOperationAlpha = blendOperationAlpha(index, attachments);
	return activeBlendState;
}

bool GraphicsState::alphaBlendActive(int index, const Attachments &attachments, bool fragmentContainsKill) const
{
	ASSERT((index >= 0) && (index < sw::MAX_COLOR_BUFFERS));

	if(!blendState[index].alphaBlendEnable)
	{
		return false;
	}

	if(!(colorWriteActive(attachments) || fragmentContainsKill))
	{
		return false;
	}

	bool colorBlend = !(blendOperation(index, attachments) == VK_BLEND_OP_SRC_EXT &&
	                    sourceBlendFactor(index) == VK_BLEND_FACTOR_ONE);
	bool alphaBlend = !(blendOperationAlpha(index, attachments) == VK_BLEND_OP_SRC_EXT &&
	                    sourceBlendFactorAlpha(index) == VK_BLEND_FACTOR_ONE);

	return colorBlend || alphaBlend;
}

VkBlendFactor GraphicsState::sourceBlendFactor(int index) const
{
	ASSERT((index >= 0) && (index < sw::MAX_COLOR_BUFFERS));

	if(!blendState[index].alphaBlendEnable) return VK_BLEND_FACTOR_ONE;

	switch(blendState[index].blendOperation)
	{
	case VK_BLEND_OP_ADD:
	case VK_BLEND_OP_SUBTRACT:
	case VK_BLEND_OP_REVERSE_SUBTRACT:
		return blendState[index].sourceBlendFactor;
	case VK_BLEND_OP_MIN:
		return VK_BLEND_FACTOR_ONE;
	case VK_BLEND_OP_MAX:
		return VK_BLEND_FACTOR_ONE;
	default:
		ASSERT(false);
	}

	return blendState[index].sourceBlendFactor;
}

VkBlendFactor GraphicsState::destBlendFactor(int index) const
{
	ASSERT((index >= 0) && (index < sw::MAX_COLOR_BUFFERS));

	if(!blendState[index].alphaBlendEnable) return VK_BLEND_FACTOR_ONE;

	switch(blendState[index].blendOperation)
	{
	case VK_BLEND_OP_ADD:
	case VK_BLEND_OP_SUBTRACT:
	case VK_BLEND_OP_REVERSE_SUBTRACT:
		return blendState[index].destBlendFactor;
	case VK_BLEND_OP_MIN:
		return VK_BLEND_FACTOR_ONE;
	case VK_BLEND_OP_MAX:
		return VK_BLEND_FACTOR_ONE;
	default:
		ASSERT(false);
	}

	return blendState[index].destBlendFactor;
}

VkBlendOp GraphicsState::blendOperation(int index, const Attachments &attachments) const
{
	ASSERT((index >= 0) && (index < sw::MAX_COLOR_BUFFERS));

	if(!blendState[index].alphaBlendEnable) return VK_BLEND_OP_SRC_EXT;

	switch(blendState[index].blendOperation)
	{
	case VK_BLEND_OP_ADD:
		if(sourceBlendFactor(index) == VK_BLEND_FACTOR_ZERO)
		{
			if(destBlendFactor(index) == VK_BLEND_FACTOR_ZERO)
			{
				return VK_BLEND_OP_ZERO_EXT;
			}
			else
			{
				return VK_BLEND_OP_DST_EXT;
			}
		}
		else if(sourceBlendFactor(index) == VK_BLEND_FACTOR_ONE)
		{
			if(destBlendFactor(index) == VK_BLEND_FACTOR_ZERO)
			{
				return VK_BLEND_OP_SRC_EXT;
			}
			else
			{
				return VK_BLEND_OP_ADD;
			}
		}
		else
		{
			if(destBlendFactor(index) == VK_BLEND_FACTOR_ZERO)
			{
				return VK_BLEND_OP_SRC_EXT;
			}
			else
			{
				return VK_BLEND_OP_ADD;
			}
		}
	case VK_BLEND_OP_SUBTRACT:
		if(sourceBlendFactor(index) == VK_BLEND_FACTOR_ZERO && attachments.isColorClamped(index))
		{
			return VK_BLEND_OP_ZERO_EXT;  // Negative, clamped to zero
		}
		else if(sourceBlendFactor(index) == VK_BLEND_FACTOR_ONE)
		{
			if(destBlendFactor(index) == VK_BLEND_FACTOR_ZERO)
			{
				return VK_BLEND_OP_SRC_EXT;
			}
			else
			{
				return VK_BLEND_OP_SUBTRACT;
			}
		}
		else
		{
			if(destBlendFactor(index) == VK_BLEND_FACTOR_ZERO)
			{
				return VK_BLEND_OP_SRC_EXT;
			}
			else
			{
				return VK_BLEND_OP_SUBTRACT;
			}
		}
	case VK_BLEND_OP_REVERSE_SUBTRACT:
		if(sourceBlendFactor(index) == VK_BLEND_FACTOR_ZERO)
		{
			if(destBlendFactor(index) == VK_BLEND_FACTOR_ZERO)
			{
				return VK_BLEND_OP_ZERO_EXT;
			}
			else
			{
				return VK_BLEND_OP_DST_EXT;
			}
		}
		else if(sourceBlendFactor(index) == VK_BLEND_FACTOR_ONE)
		{
			if(destBlendFactor(index) == VK_BLEND_FACTOR_ZERO && attachments.isColorClamped(index))
			{
				return VK_BLEND_OP_ZERO_EXT;  // Negative, clamped to zero
			}
			else
			{
				return VK_BLEND_OP_REVERSE_SUBTRACT;
			}
		}
		else
		{
			if(destBlendFactor(index) == VK_BLEND_FACTOR_ZERO && attachments.isColorClamped(index))
			{
				return VK_BLEND_OP_ZERO_EXT;  // Negative, clamped to zero
			}
			else
			{
				return VK_BLEND_OP_REVERSE_SUBTRACT;
			}
		}
	case VK_BLEND_OP_MIN:
		return VK_BLEND_OP_MIN;
	case VK_BLEND_OP_MAX:
		return VK_BLEND_OP_MAX;
	default:
		ASSERT(false);
	}

	return blendState[index].blendOperation;
}

VkBlendFactor GraphicsState::sourceBlendFactorAlpha(int index) const
{
	ASSERT((index >= 0) && (index < sw::MAX_COLOR_BUFFERS));

	switch(blendState[index].blendOperationAlpha)
	{
	case VK_BLEND_OP_ADD:
	case VK_BLEND_OP_SUBTRACT:
	case VK_BLEND_OP_REVERSE_SUBTRACT:
		return blendState[index].sourceBlendFactorAlpha;
	case VK_BLEND_OP_MIN:
		return VK_BLEND_FACTOR_ONE;
	case VK_BLEND_OP_MAX:
		return VK_BLEND_FACTOR_ONE;
	default:
		ASSERT(false);
	}

	return blendState[index].sourceBlendFactorAlpha;
}

VkBlendFactor GraphicsState::destBlendFactorAlpha(int index) const
{
	ASSERT((index >= 0) && (index < sw::MAX_COLOR_BUFFERS));

	switch(blendState[index].blendOperationAlpha)
	{
	case VK_BLEND_OP_ADD:
	case VK_BLEND_OP_SUBTRACT:
	case VK_BLEND_OP_REVERSE_SUBTRACT:
		return blendState[index].destBlendFactorAlpha;
	case VK_BLEND_OP_MIN:
		return VK_BLEND_FACTOR_ONE;
	case VK_BLEND_OP_MAX:
		return VK_BLEND_FACTOR_ONE;
	default:
		ASSERT(false);
	}

	return blendState[index].destBlendFactorAlpha;
}

VkBlendOp GraphicsState::blendOperationAlpha(int index, const Attachments &attachments) const
{
	ASSERT((index >= 0) && (index < sw::MAX_COLOR_BUFFERS));

	switch(blendState[index].blendOperationAlpha)
	{
	case VK_BLEND_OP_ADD:
		if(sourceBlendFactorAlpha(index) == VK_BLEND_FACTOR_ZERO)
		{
			if(destBlendFactorAlpha(index) == VK_BLEND_FACTOR_ZERO)
			{
				return VK_BLEND_OP_ZERO_EXT;
			}
			else
			{
				return VK_BLEND_OP_DST_EXT;
			}
		}
		else if(sourceBlendFactorAlpha(index) == VK_BLEND_FACTOR_ONE)
		{
			if(destBlendFactorAlpha(index) == VK_BLEND_FACTOR_ZERO)
			{
				return VK_BLEND_OP_SRC_EXT;
			}
			else
			{
				return VK_BLEND_OP_ADD;
			}
		}
		else
		{
			if(destBlendFactorAlpha(index) == VK_BLEND_FACTOR_ZERO)
			{
				return VK_BLEND_OP_SRC_EXT;
			}
			else
			{
				return VK_BLEND_OP_ADD;
			}
		}
	case VK_BLEND_OP_SUBTRACT:
		if(sourceBlendFactorAlpha(index) == VK_BLEND_FACTOR_ZERO && attachments.isColorClamped(index))
		{
			return VK_BLEND_OP_ZERO_EXT;  // Negative, clamped to zero
		}
		else if(sourceBlendFactorAlpha(index) == VK_BLEND_FACTOR_ONE)
		{
			if(destBlendFactorAlpha(index) == VK_BLEND_FACTOR_ZERO)
			{
				return VK_BLEND_OP_SRC_EXT;
			}
			else
			{
				return VK_BLEND_OP_SUBTRACT;
			}
		}
		else
		{
			if(destBlendFactorAlpha(index) == VK_BLEND_FACTOR_ZERO)
			{
				return VK_BLEND_OP_SRC_EXT;
			}
			else
			{
				return VK_BLEND_OP_SUBTRACT;
			}
		}
	case VK_BLEND_OP_REVERSE_SUBTRACT:
		if(sourceBlendFactorAlpha(index) == VK_BLEND_FACTOR_ZERO)
		{
			if(destBlendFactorAlpha(index) == VK_BLEND_FACTOR_ZERO)
			{
				return VK_BLEND_OP_ZERO_EXT;
			}
			else
			{
				return VK_BLEND_OP_DST_EXT;
			}
		}
		else if(sourceBlendFactorAlpha(index) == VK_BLEND_FACTOR_ONE)
		{
			if(destBlendFactorAlpha(index) == VK_BLEND_FACTOR_ZERO && attachments.isColorClamped(index))
			{
				return VK_BLEND_OP_ZERO_EXT;  // Negative, clamped to zero
			}
			else
			{
				return VK_BLEND_OP_REVERSE_SUBTRACT;
			}
		}
		else
		{
			if(destBlendFactorAlpha(index) == VK_BLEND_FACTOR_ZERO && attachments.isColorClamped(index))
			{
				return VK_BLEND_OP_ZERO_EXT;  // Negative, clamped to zero
			}
			else
			{
				return VK_BLEND_OP_REVERSE_SUBTRACT;
			}
		}
	case VK_BLEND_OP_MIN:
		return VK_BLEND_OP_MIN;
	case VK_BLEND_OP_MAX:
		return VK_BLEND_OP_MAX;
	default:
		ASSERT(false);
	}

	return blendState[index].blendOperationAlpha;
}

bool GraphicsState::colorWriteActive(const Attachments &attachments) const
{
	for(int i = 0; i < sw::MAX_COLOR_BUFFERS; i++)
	{
		if(colorWriteActive(i, attachments))
		{
			return true;
		}
	}

	return false;
}

int GraphicsState::colorWriteActive(int index, const Attachments &attachments) const
{
	ASSERT((index >= 0) && (index < sw::MAX_COLOR_BUFFERS));

	if(!attachments.colorBuffer[index] || attachments.colorBuffer[index]->getFormat() == VK_FORMAT_UNDEFINED)
	{
		return 0;
	}

	if(blendOperation(index, attachments) == VK_BLEND_OP_DST_EXT && destBlendFactor(index) == VK_BLEND_FACTOR_ONE &&
	   (blendOperationAlpha(index, attachments) == VK_BLEND_OP_DST_EXT && destBlendFactorAlpha(index) == VK_BLEND_FACTOR_ONE))
	{
		return 0;
	}

	return colorWriteMask[index];
}

}  // namespace vk