/*------------------------------------------------------------------------
 * Vulkan Conformance Tests
 * ------------------------
 *
 * Copyright (c) 2020 The Khronos Group Inc.
 * Copyright (c) 2020 Valve Corporation.
 *
 * 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.
 *
 *//*!
 * \file
 * \brief Tests with shaders that do not write to the Position built-in.
 *//*--------------------------------------------------------------------*/

#include "vktPipelineNoPositionTests.hpp"
#include "vktTestCase.hpp"

#include "vkQueryUtil.hpp"
#include "vkObjUtil.hpp"
#include "vkBuilderUtil.hpp"
#include "vkTypeUtil.hpp"
#include "vkCmdUtil.hpp"
#include "vkImageWithMemory.hpp"
#include "vkBufferWithMemory.hpp"
#include "vktPipelineImageUtil.hpp"
#include "vkImageUtil.hpp"
#include "vkBarrierUtil.hpp"
#include "vkBuilderUtil.hpp"

#include "tcuVector.hpp"
#include "tcuTestLog.hpp"

#include "deUniquePtr.hpp"

#include <vector>
#include <set>
#include <sstream>
#include <array>

namespace vkt
{
namespace pipeline
{

namespace
{

using namespace vk;

enum ShaderStageBits
{
	STAGE_VERTEX			= (1 << 0),
	STAGE_TESS_CONTROL		= (1 << 1),
	STAGE_TESS_EVALUATION	= (1 << 2),
	STAGE_GEOMETRY			= (1 << 3),
	STAGE_MASK_COUNT		= (1 << 4),
};

using ShaderStageFlags = deUint32;

constexpr deUint32 kStageCount = 4u;

static_assert((1u << kStageCount) == static_cast<deUint32>(STAGE_MASK_COUNT),
			  "Total stage count does not match stage mask bits");

struct TestParams
{
	ShaderStageFlags	selectedStages;			// Stages that will be present in the pipeline.
	ShaderStageFlags	writeStages;			// Subset of selectedStages that will write to the Position built-in.
	deUint32			numViews;				// Number of views for multiview.
	bool				explicitDeclarations;	// Explicitly declare the input and output blocks or not.
	bool				useSSBO;				// Write to an SSBO from the selected stages.

	// Commonly used checks.
	bool tessellation	(void) const { return (selectedStages & (STAGE_TESS_CONTROL | STAGE_TESS_EVALUATION));	}
	bool geometry		(void) const { return (selectedStages & STAGE_GEOMETRY);								}
};

// Generates the combinations list of stage flags for writeStages when a given subset of stages are selected.
std::vector<ShaderStageFlags> getWriteSubCases (ShaderStageFlags selectedStages)
{
	std::set<ShaderStageFlags> uniqueCases;
	for (ShaderStageFlags stages = 0; stages < STAGE_MASK_COUNT; ++stages)
		uniqueCases.insert(stages & selectedStages);
	return std::vector<ShaderStageFlags>(begin(uniqueCases), end(uniqueCases));
}

class NoPositionCase : public vkt::TestCase
{
public:
							NoPositionCase		(tcu::TestContext& testCtx, const std::string& name, const std::string& description, const TestParams& params);
	virtual					~NoPositionCase		(void) {}

	virtual void			initPrograms		(vk::SourceCollections& programCollection) const;
	virtual TestInstance*	createInstance		(Context& context) const;
	virtual void			checkSupport		(Context& context) const;

	static tcu::Vec4		getBackGroundColor	(void) { return tcu::Vec4(0.0f, 1.0f, 0.0f, 1.0f); }
	static VkFormat			getImageFormat		(void) { return VK_FORMAT_R8G8B8A8_UNORM; }
	static VkExtent3D		getImageExtent		(void) { return makeExtent3D(64u, 64u, 1u); }

private:
	TestParams				m_params;
};

class NoPositionInstance : public vkt::TestInstance
{
public:
								NoPositionInstance	(Context& context, const TestParams& params);
	virtual						~NoPositionInstance	(void) {}

	virtual tcu::TestStatus		iterate				(void);

private:
	TestParams					m_params;
};

NoPositionCase::NoPositionCase (tcu::TestContext& testCtx, const std::string& name, const std::string& description, const TestParams& params)
	: vkt::TestCase	(testCtx, name, description)
	, m_params		(params)
{
	DE_ASSERT(params.numViews >= 1u);
}

void NoPositionCase::initPrograms (vk::SourceCollections& programCollection) const
{
	// Add shaders for the selected stages and write to gl_Position in the subset of stages marked for writing.

	// Optional writes, extensions and declarations.
	std::string ssboDecl;
	std::string extensions;
	std::string vertSSBOWrite;
	std::string tescSSBOWrite;
	std::string teseSSBOWrite;
	std::string geomSSBOWrite;

	const bool multiview = (m_params.numViews > 1u);

	if (multiview)
		extensions = "#extension GL_EXT_multiview : require\n";

	if (m_params.useSSBO)
	{
		const auto stageCountStr	= de::toString(kStageCount);
		const auto ssboElementCount	= kStageCount * m_params.numViews;
		ssboDecl = "layout (set=0, binding=0, std430) buffer StorageBlock { uint counters[" + de::toString(ssboElementCount) + "]; } ssbo;\n";

		const std::array<std::string*, kStageCount> writeStrings = {{ &vertSSBOWrite, &tescSSBOWrite, &teseSSBOWrite, &geomSSBOWrite }};
		for (size_t i = 0; i < writeStrings.size(); ++i)
			*writeStrings[i] = "    atomicAdd(ssbo.counters[" + de::toString(i) + (multiview ? (" + uint(gl_ViewIndex) * " + stageCountStr) : "") + "], 1u);\n";
	}

	if (m_params.selectedStages & STAGE_VERTEX)
	{
		std::ostringstream vert;
		vert
			<< "#version 450\n"
			<< extensions
			<< ssboDecl
			<< "layout (location=0) in vec4 in_pos;\n"
			<< (m_params.explicitDeclarations ?
				"out gl_PerVertex\n"
				"{\n"
				"    vec4 gl_Position;\n"
				"    float gl_PointSize;\n"
				"    float gl_ClipDistance[];\n"
				"    float gl_CullDistance[];\n"
				"};\n"
				: "")
			<< "void main (void)\n"
			<< "{\n"
			<< ((m_params.writeStages & STAGE_VERTEX) ? "    gl_Position = in_pos;\n" : "")
			<< vertSSBOWrite
			<< "}\n"
			;

		programCollection.glslSources.add("vert") << glu::VertexSource(vert.str());
	}

	if (m_params.selectedStages & STAGE_TESS_CONTROL)
	{
		std::ostringstream tesc;
		tesc
			<< "#version 450\n"
			<< extensions
			<< ssboDecl
			<< "layout (vertices = 3) out;\n"
			<< (m_params.explicitDeclarations ?
				"in gl_PerVertex\n"
				"{\n"
				"    vec4 gl_Position;\n"
				"    float gl_PointSize;\n"
				"    float gl_ClipDistance[];\n"
				"    float gl_CullDistance[];\n"
				"} gl_in[gl_MaxPatchVertices];\n"
				"out gl_PerVertex\n"
				"{\n"
				"    vec4 gl_Position;\n"
				"    float gl_PointSize;\n"
				"    float gl_ClipDistance[];\n"
				"    float gl_CullDistance[];\n"
				"} gl_out[];\n"
				: "")
			<< "void main (void)\n"
			<< "{\n"
			<< "    gl_TessLevelInner[0] = 1.0;\n"
			<< "    gl_TessLevelInner[1] = 1.0;\n"
			<< "    gl_TessLevelOuter[0] = 1.0;\n"
			<< "    gl_TessLevelOuter[1] = 1.0;\n"
			<< "    gl_TessLevelOuter[2] = 1.0;\n"
			<< "    gl_TessLevelOuter[3] = 1.0;\n"
			<< "\n"
			<< ((m_params.writeStages & STAGE_TESS_CONTROL) ? "    gl_out[gl_InvocationID].gl_Position = gl_in[gl_InvocationID].gl_Position;\n" : "")
			<< tescSSBOWrite
			<< "}\n"
			;

		programCollection.glslSources.add("tesc") << glu::TessellationControlSource(tesc.str());
	}

	if (m_params.selectedStages & STAGE_TESS_EVALUATION)
	{
		std::ostringstream tese;
		tese
			<< "#version 450\n"
			<< extensions
			<< ssboDecl
			<< "layout (triangles, fractional_odd_spacing, cw) in;\n"
			<< (m_params.explicitDeclarations ?
				"in gl_PerVertex\n"
				"{\n"
				"    vec4 gl_Position;\n"
				"    float gl_PointSize;\n"
				"    float gl_ClipDistance[];\n"
				"    float gl_CullDistance[];\n"
				"} gl_in[gl_MaxPatchVertices];\n"
				"out gl_PerVertex\n"
				"{\n"
				"    vec4 gl_Position;\n"
				"    float gl_PointSize;\n"
				"    float gl_ClipDistance[];\n"
				"    float gl_CullDistance[];\n"
				"};\n"
				: "")
			<< "void main (void)\n"
			<< "{\n"
			<< ((m_params.writeStages & STAGE_TESS_EVALUATION) ?
				"    gl_Position = (gl_TessCoord.x * gl_in[0].gl_Position) +\n"
				"                  (gl_TessCoord.y * gl_in[1].gl_Position) +\n"
				"                  (gl_TessCoord.z * gl_in[2].gl_Position);\n"
				: "")
			<< teseSSBOWrite
			<< "}\n"
			;

		programCollection.glslSources.add("tese") << glu::TessellationEvaluationSource(tese.str());
	}

	if (m_params.selectedStages & STAGE_GEOMETRY)
	{
		std::ostringstream geom;
		geom
			<< "#version 450\n"
			<< extensions
			<< ssboDecl
			<< "layout (triangles) in;\n"
			<< "layout (triangle_strip, max_vertices=3) out;\n"
			<< (m_params.explicitDeclarations ?
				"in gl_PerVertex\n"
				"{\n"
				"    vec4 gl_Position;\n"
				"    float gl_PointSize;\n"
				"    float gl_ClipDistance[];\n"
				"    float gl_CullDistance[];\n"
				"} gl_in[3];\n"
				"out gl_PerVertex\n"
				"{\n"
				"    vec4 gl_Position;\n"
				"    float gl_PointSize;\n"
				"    float gl_ClipDistance[];\n"
				"    float gl_CullDistance[];\n"
				"};\n"
				: "")
			<< "void main (void)\n"
			<< "{\n"
			<< "    for (int i = 0; i < 3; i++)\n"
			<< "    {\n"
			<< ((m_params.writeStages & STAGE_GEOMETRY) ? "        gl_Position = gl_in[i].gl_Position;\n" : "")
			<< "        EmitVertex();\n"
			<< "    }\n"
			<< geomSSBOWrite
			<< "}\n"
			;

		programCollection.glslSources.add("geom") << glu::GeometrySource(geom.str());
	}

	{
		const auto backgroundColor = getBackGroundColor();

		std::ostringstream colorStr;
		colorStr << "vec4(" << backgroundColor.x() << ", " << backgroundColor.y() << ", " << backgroundColor.z() << ", " << backgroundColor.w() << ")";

		std::ostringstream frag;
		frag
			<< "#version 450\n"
			<< "layout (location=0) out vec4 out_color;\n"
			<< "void main (void)\n"
			<< "{\n"
			<< "    out_color = " << colorStr.str() << ";\n"
			<< "}\n"
			;

		programCollection.glslSources.add("frag") << glu::FragmentSource(frag.str());
	}
}

TestInstance* NoPositionCase::createInstance (Context& context) const
{
	return new NoPositionInstance (context, m_params);
}

void NoPositionCase::checkSupport (Context& context) const
{
	const auto features	= getPhysicalDeviceFeatures(context.getInstanceInterface(), context.getPhysicalDevice());
	const bool hasTess	= m_params.tessellation();
	const bool hasGeom	= m_params.geometry();

	if (hasTess && !features.tessellationShader)
		TCU_THROW(NotSupportedError, "Tessellation shaders not supported");

	if (hasGeom && !features.geometryShader)
		TCU_THROW(NotSupportedError, "Geometry shaders not supported");

	if (m_params.numViews > 1u)
	{
		context.requireDeviceFunctionality("VK_KHR_multiview");
		const auto& multiviewFeatures = context.getMultiviewFeatures();

		if (!multiviewFeatures.multiview)
			TCU_THROW(NotSupportedError, "Multiview not supported");

		if (hasTess && !multiviewFeatures.multiviewTessellationShader)
			TCU_THROW(NotSupportedError, "Multiview not supported with tessellation shaders");

		if (hasGeom && !multiviewFeatures.multiviewGeometryShader)
			TCU_THROW(NotSupportedError, "Multiview not supported with geometry shaders");
	}

	if (m_params.useSSBO)
	{
		if (!features.vertexPipelineStoresAndAtomics)
			TCU_THROW(NotSupportedError, "Vertex pipeline stores and atomics not supported");
	}
}

NoPositionInstance::NoPositionInstance (Context& context, const TestParams& params)
	: vkt::TestInstance	(context)
	, m_params			(params)
{}

tcu::TestStatus NoPositionInstance::iterate (void)
{
	const	auto&				vkd			= m_context.getDeviceInterface();
	const	auto				device		= m_context.getDevice();
	const	auto				queue		= m_context.getUniversalQueue();
	const	auto				qIndex		= m_context.getUniversalQueueFamilyIndex();
			auto&				alloc		= m_context.getDefaultAllocator();
	const	auto				format		= NoPositionCase::getImageFormat();
	const	auto				extent		= NoPositionCase::getImageExtent();
	const	auto				color		= NoPositionCase::getBackGroundColor();
	const	VkImageUsageFlags	usage		= (VK_IMAGE_USAGE_TRANSFER_SRC_BIT | VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT);
	const	bool				tess		= m_params.tessellation();
			VkShaderStageFlags	stageFlags	= 0u;

	// Shader modules.
	Move<VkShaderModule> vert;
	Move<VkShaderModule> tesc;
	Move<VkShaderModule> tese;
	Move<VkShaderModule> geom;
	Move<VkShaderModule> frag;

	if (m_params.selectedStages & STAGE_VERTEX)
	{
		vert = createShaderModule(vkd, device, m_context.getBinaryCollection().get("vert"), 0u);
		stageFlags |= VK_SHADER_STAGE_VERTEX_BIT;
	}
	if (m_params.selectedStages & STAGE_TESS_CONTROL)
	{
		tesc = createShaderModule(vkd, device, m_context.getBinaryCollection().get("tesc"), 0u);
		stageFlags |= VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT;
	}
	if (m_params.selectedStages & STAGE_TESS_EVALUATION)
	{
		tese = createShaderModule(vkd, device, m_context.getBinaryCollection().get("tese"), 0u);
		stageFlags |= VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT;
	}
	if (m_params.selectedStages & STAGE_GEOMETRY)
	{
		geom = createShaderModule(vkd, device, m_context.getBinaryCollection().get("geom"), 0u);
		stageFlags |= VK_SHADER_STAGE_GEOMETRY_BIT;
	}

	frag = createShaderModule(vkd, device, m_context.getBinaryCollection().get("frag"), 0u);
	stageFlags |= VK_SHADER_STAGE_FRAGMENT_BIT;

	// Color attachment.
	const VkImageCreateInfo colorImageInfo =
	{
		VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO,	//	VkStructureType			sType;
		nullptr,								//	const void*				pNext;
		0u,										//	VkImageCreateFlags		flags;
		VK_IMAGE_TYPE_2D,						//	VkImageType				imageType;
		format,									//	VkFormat				format;
		extent,									//	VkExtent3D				extent;
		1u,										//	deUint32				mipLevels;
		m_params.numViews,						//	deUint32				arrayLayers;
		VK_SAMPLE_COUNT_1_BIT,					//	VkSampleCountFlagBits	samples;
		VK_IMAGE_TILING_OPTIMAL,				//	VkImageTiling			tiling;
		usage,									//	VkImageUsageFlags		usage;
		VK_SHARING_MODE_EXCLUSIVE,				//	VkSharingMode			sharingMode;
		0u,										//	deUint32				queueFamilyIndexCount;
		nullptr,								//	const deUint32*			pQueueFamilyIndices;
		VK_IMAGE_LAYOUT_UNDEFINED,				//	VkImageLayout			initialLayout;
	};
	ImageWithMemory colorImage (vkd, device, alloc, colorImageInfo, MemoryRequirement::Any);

	const auto subresourceRange	= makeImageSubresourceRange(VK_IMAGE_ASPECT_COLOR_BIT, 0u, 1u, 0u, m_params.numViews);
	const auto colorImageView	= makeImageView(vkd, device, colorImage.get(), VK_IMAGE_VIEW_TYPE_2D, format, subresourceRange);

	// Vertices and vertex buffer.
	std::vector<tcu::Vec4> vertices =
	{
		tcu::Vec4( 0.0f, -0.5f,  0.0f,  1.0f),
		tcu::Vec4( 0.5f,  0.5f,  0.0f,  1.0f),
		tcu::Vec4(-0.5f,  0.5f,  0.0f,  1.0f),
	};

	const auto vertexBufferSize		= static_cast<VkDeviceSize>(vertices.size() * sizeof(decltype(vertices)::value_type));
	const auto vertexBufferInfo		= makeBufferCreateInfo(vertexBufferSize, VK_BUFFER_USAGE_VERTEX_BUFFER_BIT);
	const auto vertexBufferOffset	= static_cast<VkDeviceSize>(0);
	BufferWithMemory vertexBuffer (vkd, device, alloc, vertexBufferInfo, MemoryRequirement::HostVisible);

	auto& vertexBufferAlloc	= vertexBuffer.getAllocation();
	void* vertexBufferPtr	= vertexBufferAlloc.getHostPtr();
	deMemcpy(vertexBufferPtr, vertices.data(), static_cast<size_t>(vertexBufferSize));
	flushAlloc(vkd, device, vertexBufferAlloc);

	// Render pass.
	const VkAttachmentDescription colorAttachment =
	{
		0u,											//	VkAttachmentDescriptionFlags	flags;
		format,										//	VkFormat						format;
		VK_SAMPLE_COUNT_1_BIT,						//	VkSampleCountFlagBits			samples;
		VK_ATTACHMENT_LOAD_OP_CLEAR,				//	VkAttachmentLoadOp				loadOp;
		VK_ATTACHMENT_STORE_OP_STORE,				//	VkAttachmentStoreOp				storeOp;
		VK_ATTACHMENT_LOAD_OP_DONT_CARE,			//	VkAttachmentLoadOp				stencilLoadOp;
		VK_ATTACHMENT_STORE_OP_DONT_CARE,			//	VkAttachmentStoreOp				stencilStoreOp;
		VK_IMAGE_LAYOUT_UNDEFINED,					//	VkImageLayout					initialLayout;
		VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,	//	VkImageLayout					finalLayout;
	};

	const VkAttachmentReference colorAttachmentReference =
	{
		0u,											//	deUint32		attachment;
		VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,	//	VkImageLayout	layout;
	};

	const VkSubpassDescription subpassDescription =
	{
		0u,									//	VkSubpassDescriptionFlags		flags;
		VK_PIPELINE_BIND_POINT_GRAPHICS,	//	VkPipelineBindPoint				pipelineBindPoint;
		0u,									//	deUint32						inputAttachmentCount;
		nullptr,							//	const VkAttachmentReference*	pInputAttachments;
		1u,									//	deUint32						colorAttachmentCount;
		&colorAttachmentReference,			//	const VkAttachmentReference*	pColorAttachments;
		0u,									//	const VkAttachmentReference*	pResolveAttachments;
		nullptr,							//	const VkAttachmentReference*	pDepthStencilAttachment;
		0u,									//	deUint32						preserveAttachmentCount;
		nullptr,							//	const deUint32*					pPreserveAttachments;
	};

	de::MovePtr<VkRenderPassMultiviewCreateInfo>	multiviewInfo;
	deUint32										viewMask		= 0u;
	deUint32										correlationMask	= 0u;

	if (m_params.numViews > 1u)
	{
		for (deUint32 viewIdx = 0u; viewIdx < m_params.numViews; ++viewIdx)
		{
			viewMask		|= (1 << viewIdx);
			correlationMask	|= (1 << viewIdx);
		}

		multiviewInfo = de::MovePtr<VkRenderPassMultiviewCreateInfo>(new VkRenderPassMultiviewCreateInfo
		{
			VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO,	//	VkStructureType	sType;
			nullptr,												//	const void*		pNext;
			1u,														//	deUint32		subpassCount;
			&viewMask,												//	const deUint32*	pViewMasks;
			0u,														//	deUint32		dependencyCount;
			nullptr,												//	const deInt32*	pViewOffsets;
			1u,														//	deUint32		correlationMaskCount;
			&correlationMask,										//	const deUint32*	pCorrelationMasks;
		});
	}

	const VkRenderPassCreateInfo renderPassInfo =
	{
		VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO,	//	VkStructureType					sType;
		multiviewInfo.get(),						//	const void*						pNext;
		0u,											//	VkRenderPassCreateFlags			flags;
		1u,											//	deUint32						attachmentCount;
		&colorAttachment,							//	const VkAttachmentDescription*	pAttachments;
		1u,											//	deUint32						subpassCount;
		&subpassDescription,						//	const VkSubpassDescription*		pSubpasses;
		0u,											//	deUint32						dependencyCount;
		nullptr,									//	const VkSubpassDependency*		pDependencies;
	};

	const auto renderPass = createRenderPass(vkd, device, &renderPassInfo);

	// Framebuffer.
	const auto framebuffer = makeFramebuffer(vkd, device, renderPass.get(), colorImageView.get(), extent.width, extent.height);

	// Descriptor set layout and pipeline layout.
	DescriptorSetLayoutBuilder layoutBuilder;
	if (m_params.useSSBO)
	{
		layoutBuilder.addSingleBinding(VK_DESCRIPTOR_TYPE_STORAGE_BUFFER, stageFlags);
	}
	const auto descriptorSetLayout	= layoutBuilder.build(vkd, device);
	const auto pipelineLayout		= makePipelineLayout(vkd, device, descriptorSetLayout.get());

	// Pipeline.
	const std::vector<VkViewport>	viewports		(1u, makeViewport(extent));
	const std::vector<VkRect2D>		scissors		(1u, makeRect2D(extent));

	const deUint32	patchControlPoints	= (tess ? 3u : 0u);
	const auto		primitiveTopology	= (tess ? VK_PRIMITIVE_TOPOLOGY_PATCH_LIST : VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST);

	const auto pipeline = makeGraphicsPipeline(
		vkd, device, pipelineLayout.get(),
		vert.get(), tesc.get(), tese.get(), geom.get(), frag.get(),
		renderPass.get(), viewports, scissors, primitiveTopology,
		0u /* Subpass */, patchControlPoints);

	// Descriptor set and output SSBO if needed.
	Move<VkDescriptorPool>			descriptorPool;
	Move<VkDescriptorSet>			descriptorSet;
	de::MovePtr<BufferWithMemory>	ssboBuffer;
	const auto						ssboElementCount	= kStageCount * m_params.numViews;
	const auto						ssboBufferSize		= static_cast<VkDeviceSize>(ssboElementCount * sizeof(deUint32));

	if (m_params.useSSBO)
	{
		// Output SSBO.
		const auto	ssboBufferInfo	= makeBufferCreateInfo(ssboBufferSize, VK_BUFFER_USAGE_STORAGE_BUFFER_BIT);
					ssboBuffer		= de::MovePtr<BufferWithMemory>(new BufferWithMemory(vkd, device, alloc, ssboBufferInfo, MemoryRequirement::HostVisible));
		auto&		ssboBufferAlloc	= ssboBuffer->getAllocation();

		deMemset(ssboBufferAlloc.getHostPtr(), 0, static_cast<size_t>(ssboBufferSize));
		flushAlloc(vkd, device, ssboBufferAlloc);

		// Descriptor pool.
		DescriptorPoolBuilder poolBuilder;
		poolBuilder.addType(VK_DESCRIPTOR_TYPE_STORAGE_BUFFER);
		descriptorPool = poolBuilder.build(vkd, device, VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT, 1u);

		// Descriptor set.
		descriptorSet = makeDescriptorSet(vkd, device, descriptorPool.get(), descriptorSetLayout.get());
		const auto ssboWriteInfo = makeDescriptorBufferInfo(ssboBuffer->get(), 0ull, ssboBufferSize);
		DescriptorSetUpdateBuilder updateBuilder;
		updateBuilder.writeSingle(descriptorSet.get(), DescriptorSetUpdateBuilder::Location::binding(0u), VK_DESCRIPTOR_TYPE_STORAGE_BUFFER, &ssboWriteInfo);
		updateBuilder.update(vkd, device);
	}

	// Output verification buffer.
	const auto tcuFormat	= mapVkFormat(format);
	const auto pixelSize	= static_cast<deUint32>(tcu::getPixelSize(tcuFormat));
	const auto layerPixels	= extent.width * extent.height;
	const auto layerBytes	= layerPixels * pixelSize;
	const auto totalPixels	= layerPixels * m_params.numViews;
	const auto totalBytes	= totalPixels * pixelSize;

	const auto verificationBufferInfo = makeBufferCreateInfo(totalBytes, VK_BUFFER_USAGE_TRANSFER_DST_BIT);
	BufferWithMemory verificationBuffer(vkd, device, alloc, verificationBufferInfo, MemoryRequirement::HostVisible);

	// Command pool and buffer.
	const auto cmdPool		= makeCommandPool(vkd, device, qIndex);
	const auto cmdBufferPtr	= allocateCommandBuffer(vkd, device, cmdPool.get(), VK_COMMAND_BUFFER_LEVEL_PRIMARY);
	const auto cmdBuffer	= cmdBufferPtr.get();

	// Render triangle.
	beginCommandBuffer(vkd, cmdBuffer);
	beginRenderPass(vkd, cmdBuffer, renderPass.get(), framebuffer.get(), scissors.front(), color);
	vkd.cmdBindPipeline(cmdBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline.get());
	vkd.cmdBindVertexBuffers(cmdBuffer, 0u, 1u, &vertexBuffer.get(), &vertexBufferOffset);
	if (m_params.useSSBO)
		vkd.cmdBindDescriptorSets(cmdBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout.get(), 0u, 1u, &descriptorSet.get(), 0u, nullptr);
	vkd.cmdDraw(cmdBuffer, static_cast<deUint32>(vertices.size()), 1u, 0u, 0u);
	endRenderPass(vkd, cmdBuffer);

	// Copy output image to verification buffer.
	const auto preTransferBarrier = makeImageMemoryBarrier(VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT, VK_ACCESS_TRANSFER_READ_BIT, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL, colorImage.get(), subresourceRange);
	vkd.cmdPipelineBarrier(cmdBuffer, VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT, 0u, 0u, nullptr, 0u, nullptr, 1u, &preTransferBarrier);

	const auto				subresourceLayers	= makeImageSubresourceLayers(VK_IMAGE_ASPECT_COLOR_BIT, 0u, 0u, m_params.numViews);
	const VkBufferImageCopy	copyRegion			=
	{
		0ull,					//	VkDeviceSize				bufferOffset;
		0u,						//	deUint32					bufferRowLength;
		0u,						//	deUint32					bufferImageHeight;
		subresourceLayers,		//	VkImageSubresourceLayers	imageSubresource;
		makeOffset3D(0, 0, 0),	//	VkOffset3D					imageOffset;
		extent,					//	VkExtent3D					imageExtent;
	};
	vkd.cmdCopyImageToBuffer(cmdBuffer, colorImage.get(), VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL, verificationBuffer.get(), 1u, &copyRegion);

	const auto postTransferBarrier = makeMemoryBarrier(VK_ACCESS_TRANSFER_WRITE_BIT, VK_ACCESS_HOST_READ_BIT);
	vkd.cmdPipelineBarrier(cmdBuffer, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_HOST_BIT, 0u, 1u, &postTransferBarrier, 0u, nullptr, 0u, nullptr);

	// Output SSBO to host barrier.
	if (m_params.useSSBO)
	{
		const auto ssboBarrier = makeMemoryBarrier(VK_ACCESS_SHADER_WRITE_BIT, VK_ACCESS_HOST_READ_BIT);
		vkd.cmdPipelineBarrier(cmdBuffer, VK_PIPELINE_STAGE_ALL_GRAPHICS_BIT, VK_PIPELINE_STAGE_HOST_BIT, 0u, 1u, &ssboBarrier, 0u, nullptr, 0u, nullptr);
	}

	// Submit commands.
	endCommandBuffer(vkd, cmdBuffer);
	submitCommandsAndWait(vkd, device, queue, cmdBuffer);

	// Verify the image has the background color.
	auto&	verificationBufferAlloc	= verificationBuffer.getAllocation();
	auto	verificationBufferPtr	= reinterpret_cast<const char*>(verificationBufferAlloc.getHostPtr());
	invalidateAlloc(vkd, device, verificationBufferAlloc);

	const auto iWidth	= static_cast<int>(extent.width);
	const auto iHeight	= static_cast<int>(extent.height);
	const auto iDepth	= static_cast<int>(extent.depth);

	for (deUint32 layer = 0u; layer < m_params.numViews; ++layer)
	{
		const auto pixels = tcu::ConstPixelBufferAccess(tcuFormat, iWidth, iHeight, iDepth, reinterpret_cast<const void*>(verificationBufferPtr + layer * layerBytes));

		for (int y = 0; y < iHeight;	++y)
		for (int x = 0; x < iWidth;		++x)
		{
			const auto pixel = pixels.getPixel(x, y);
			if (pixel != color)
			{
				std::ostringstream msg;
				msg << "Unexpected color found at pixel (" << x << ", " << y << ") in layer " << layer;

				auto& log = m_context.getTestContext().getLog();
				log << tcu::TestLog::Message << msg.str() << tcu::TestLog::EndMessage;
				log << tcu::TestLog::Image("Result", "Result Image", pixels);
				TCU_FAIL(msg.str());
			}
		}
	}

	// Verify SSBO if used.
	if (m_params.useSSBO)
	{
		// Get stored counters.
		const auto	ssboBufferSizeSz	= static_cast<size_t>(ssboBufferSize);
		auto&		ssboAlloc			= ssboBuffer->getAllocation();
		invalidateAlloc(vkd, device, ssboAlloc);

		std::vector<deUint32> ssboCounters;
		ssboCounters.resize(ssboElementCount);
		DE_ASSERT(ssboBufferSizeSz == ssboCounters.size() * sizeof(decltype(ssboCounters)::value_type));
		deMemcpy(ssboCounters.data(), ssboAlloc.getHostPtr(), ssboBufferSizeSz);

		// Minimum accepted counter values.
		// Vertex, Tesellation Evaluation, Tessellation Control, Geometry.
		deUint32 expectedCounters[kStageCount] = { 3u, 3u, 3u, 1u };

		// Verify.
		for (deUint32 viewIdx = 0u; viewIdx < m_params.numViews; ++viewIdx)
		for (deUint32 stageIdx = 0u; stageIdx < kStageCount; ++stageIdx)
		{
			// If the stage is not selected, the expected value is exactly zero. Otherwise, it must be at least as expectedCounters.
			const deUint32	minVal		= ((m_params.selectedStages & (1u << stageIdx)) ? expectedCounters[stageIdx] : 0u);
			const deUint32	storedVal	= ssboCounters[stageIdx + viewIdx * kStageCount];
			const bool		ok			= ((minVal == 0u) ? (storedVal == minVal) : (storedVal >= minVal));

			if (!ok)
			{
				const char* stageNames[kStageCount] =
				{
					"vertex",
					"tessellation evaluation",
					"tessellation control",
					"geometry",
				};

				std::ostringstream msg;
				msg << "Unexpected SSBO counter value in view " << viewIdx
					<< " for the " << stageNames[stageIdx] << " shader:"
					<< " got " << storedVal << " but expected " << minVal;
				TCU_FAIL(msg.str());
			}
		}
	}

	return tcu::TestStatus::pass("Pass");
}

} // anonymous

tcu::TestCaseGroup*	createNoPositionTests (tcu::TestContext& testCtx)
{
	de::MovePtr<tcu::TestCaseGroup> group(new tcu::TestCaseGroup(testCtx, "no_position", "Tests with shaders that do not write to the Position built-in"));

	for (int aux = 0; aux < 2; ++aux)
	{
		const bool						explicitDeclarations	= (aux == 1);
		const std::string				declGroupName			(explicitDeclarations ? "explicit_declarations" : "implicit_declarations");
		de::MovePtr<tcu::TestCaseGroup>	declGroup				(new tcu::TestCaseGroup(testCtx, declGroupName.c_str(), ""));

		for (int aux2 = 0; aux2 < 2; ++aux2)
		{
			const bool useSSBO = (aux2 == 1);
			const std::string ssboGroupName (useSSBO ? "ssbo_writes" : "basic");
			de::MovePtr<tcu::TestCaseGroup> ssboGroup (new tcu::TestCaseGroup(testCtx, ssboGroupName.c_str(), ""));

			for (deUint32 viewCount = 1u; viewCount <= 2u; ++viewCount)
			{
				const std::string				viewGroupName	((viewCount == 1u) ? "single_view" : "multiview");
				de::MovePtr<tcu::TestCaseGroup>	viewGroup		(new tcu::TestCaseGroup(testCtx, viewGroupName.c_str(), ""));

				for (ShaderStageFlags stages = 0u; stages < STAGE_MASK_COUNT; ++stages)
				{
					// Vertex must always be present.
					if (! (stages & STAGE_VERTEX))
						continue;

					// Tessellation stages must both be present or none must be.
					if (static_cast<bool>(stages & STAGE_TESS_CONTROL) != static_cast<bool>(stages & STAGE_TESS_EVALUATION))
						continue;

					const auto writeMaskCases = getWriteSubCases(stages);
					for (const auto writeMask : writeMaskCases)
					{
						std::string testName;
						if (stages & STAGE_VERTEX)			testName += (testName.empty() ? "" : "_") + std::string("v") + ((writeMask & STAGE_VERTEX)			? "1" : "0");
						if (stages & STAGE_TESS_CONTROL)	testName += (testName.empty() ? "" : "_") + std::string("c") + ((writeMask & STAGE_TESS_CONTROL)	? "1" : "0");
						if (stages & STAGE_TESS_EVALUATION)	testName += (testName.empty() ? "" : "_") + std::string("e") + ((writeMask & STAGE_TESS_EVALUATION)	? "1" : "0");
						if (stages & STAGE_GEOMETRY)		testName += (testName.empty() ? "" : "_") + std::string("g") + ((writeMask & STAGE_GEOMETRY)		? "1" : "0");

						TestParams params = { stages, writeMask, viewCount, explicitDeclarations, true };
						viewGroup->addChild(new NoPositionCase(testCtx, testName, "", params));
					}
				}

				ssboGroup->addChild(viewGroup.release());
			}

			declGroup->addChild(ssboGroup.release());
		}

		group->addChild(declGroup.release());
	}

	return group.release();
}

} // pipeline
} // vkt