procedural-3d-engine/examples/raytracingtextures/raytracingtextures.cpp

/*
 * Vulkan Example - Texture mapping with transparency using accelerated ray tracing example
 *
 * Copyright (C) 2024 by Sascha Willems - www.saschawillems.de
 *
 * This code is licensed under the MIT license (MIT) (http://opensource.org/licenses/MIT)
 */

/*
 * This hardware accelerated ray tracing sample renders a texture mapped quad with transparency
 * The sample also makes use of buffer device addresses to pass references for vertex and index buffers
 * to the shader, making data access a bit more straightforward than using descriptors.
 * Buffer references themselves are then simply set at draw time using push constants.
 * In addition to a closest hit shader, that now samples from the texture, an any hit shader is
 * added to the closest hit shader group. We use this shader to check if the texel we want to
 * sample at the currently hit ray position is transparent, and if that's the case the any hit
 * shader will cancel the intersection.
 */

#include "VulkanRaytracingSample.h"

class VulkanExample : public VulkanRaytracingSample
{
public:
	AccelerationStructure bottomLevelAS{};
	AccelerationStructure topLevelAS{};

	vks::Buffer vertexBuffer;
	vks::Buffer indexBuffer;
	uint32_t indexCount;
	vks::Buffer transformBuffer;
	std::vector<VkRayTracingShaderGroupCreateInfoKHR> shaderGroups{};
	struct ShaderBindingTables {
		ShaderBindingTable raygen;
		ShaderBindingTable miss;
		ShaderBindingTable hit;
	} shaderBindingTables;

	vks::Texture2D texture;

	struct UniformData {
		glm::mat4 viewInverse;
		glm::mat4 projInverse;
	} uniformData;
	vks::Buffer ubo;

	VkPipeline pipeline;
	VkPipelineLayout pipelineLayout;
	VkDescriptorSet descriptorSet;
	VkDescriptorSetLayout descriptorSetLayout;

	VulkanExample() : VulkanRaytracingSample()
	{
		title = "Ray tracing textures";
		camera.type = Camera::CameraType::lookat;
		camera.setPerspective(60.0f, (float)width / (float)height, 0.1f, 512.0f);
		camera.setRotation(glm::vec3(45.0f, 0.0f, 0.0f));
		camera.setTranslation(glm::vec3(0.0f, 0.0f, -1.0f));
		enableExtensions();
		// Buffer device address requires the 64-bit integer feature to be enabled
		enabledFeatures.shaderInt64 = VK_TRUE;
	}

	~VulkanExample()
	{
		vkDestroyPipeline(device, pipeline, nullptr);
		vkDestroyPipelineLayout(device, pipelineLayout, nullptr);
		vkDestroyDescriptorSetLayout(device, descriptorSetLayout, nullptr);
		deleteStorageImage();
		deleteAccelerationStructure(bottomLevelAS);
		deleteAccelerationStructure(topLevelAS);
		vertexBuffer.destroy();
		indexBuffer.destroy();
		transformBuffer.destroy();
		shaderBindingTables.raygen.destroy();
		shaderBindingTables.miss.destroy();
		shaderBindingTables.hit.destroy();
		ubo.destroy();
		texture.destroy();
	}

	void createAccelerationStructureBuffer(AccelerationStructure &accelerationStructure, VkAccelerationStructureBuildSizesInfoKHR buildSizeInfo)
	{
		VkBufferCreateInfo bufferCreateInfo{};
		bufferCreateInfo.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
		bufferCreateInfo.size = buildSizeInfo.accelerationStructureSize;
		bufferCreateInfo.usage = VK_BUFFER_USAGE_ACCELERATION_STRUCTURE_STORAGE_BIT_KHR | VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT;
		VK_CHECK_RESULT(vkCreateBuffer(device, &bufferCreateInfo, nullptr, &accelerationStructure.buffer));
		VkMemoryRequirements memoryRequirements{};
		vkGetBufferMemoryRequirements(device, accelerationStructure.buffer, &memoryRequirements);
		VkMemoryAllocateFlagsInfo memoryAllocateFlagsInfo{};
		memoryAllocateFlagsInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_FLAGS_INFO;
		memoryAllocateFlagsInfo.flags = VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_BIT_KHR;
		VkMemoryAllocateInfo memoryAllocateInfo{};
		memoryAllocateInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
		memoryAllocateInfo.pNext = &memoryAllocateFlagsInfo;
		memoryAllocateInfo.allocationSize = memoryRequirements.size;
		memoryAllocateInfo.memoryTypeIndex = vulkanDevice->getMemoryType(memoryRequirements.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
		VK_CHECK_RESULT(vkAllocateMemory(device, &memoryAllocateInfo, nullptr, &accelerationStructure.memory));
		VK_CHECK_RESULT(vkBindBufferMemory(device, accelerationStructure.buffer, accelerationStructure.memory, 0));
	}

	/*
		Create the bottom level acceleration structure contains the scene's actual geometry (vertices, triangles)
	*/
	void createBottomLevelAccelerationStructure()
	{
		// Setup vertices for a single triangle
		struct Vertex {
			float pos[3];
			float normal[3];
			float uv[2];
		};
		std::vector<Vertex> vertices = {
			{ {  0.5f,  0.5f, 0.0f }, {.0f, .0f, -1.0f}, { 1.0f, 1.0f} },
			{ {  -.5f,  0.5f, 0.0f }, {.0f, .0f, -1.0f}, { 0.0f, 1.0f} },
			{ {  -.5f,  -.5f, 0.0f }, {.0f, .0f, -1.0f}, { 0.0f, 0.0f} },
			{ {  0.5f,  -.5f, 0.0f }, {.0f, .0f, -1.0f}, { 1.0f, 0.0f} },
		};

		// Setup indices
		std::vector<uint32_t> indices = { 0, 1, 2, 0, 3, 2 };
		indexCount = static_cast<uint32_t>(indices.size());

		// Setup identity transform matrix
		VkTransformMatrixKHR transformMatrix = {
			1.0f, 0.0f, 0.0f, 0.0f,
			0.0f, 1.0f, 0.0f, 0.0f,
			0.0f, 0.0f, 1.0f, 0.0f
		};

		// Create buffers
		// For the sake of simplicity we won't stage the vertex data to the GPU memory
		// Vertex buffer
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT | VK_BUFFER_USAGE_ACCELERATION_STRUCTURE_BUILD_INPUT_READ_ONLY_BIT_KHR | VK_BUFFER_USAGE_STORAGE_BUFFER_BIT,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&vertexBuffer,
			vertices.size() * sizeof(Vertex),
			vertices.data()));
		// Index buffer
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT | VK_BUFFER_USAGE_ACCELERATION_STRUCTURE_BUILD_INPUT_READ_ONLY_BIT_KHR | VK_BUFFER_USAGE_STORAGE_BUFFER_BIT,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&indexBuffer,
			indices.size() * sizeof(uint32_t),
			indices.data()));
		// Transform buffer
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT | VK_BUFFER_USAGE_ACCELERATION_STRUCTURE_BUILD_INPUT_READ_ONLY_BIT_KHR,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&transformBuffer,
			sizeof(VkTransformMatrixKHR),
			&transformMatrix));

		VkDeviceOrHostAddressConstKHR vertexBufferDeviceAddress{};
		VkDeviceOrHostAddressConstKHR indexBufferDeviceAddress{};
		VkDeviceOrHostAddressConstKHR transformBufferDeviceAddress{};
		
		vertexBufferDeviceAddress.deviceAddress = getBufferDeviceAddress(vertexBuffer.buffer);
		indexBufferDeviceAddress.deviceAddress = getBufferDeviceAddress(indexBuffer.buffer);
		transformBufferDeviceAddress.deviceAddress = getBufferDeviceAddress(transformBuffer.buffer);

		// Build
		VkAccelerationStructureGeometryKHR accelerationStructureGeometry{};
		accelerationStructureGeometry.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_KHR;
		accelerationStructureGeometry.geometryType = VK_GEOMETRY_TYPE_TRIANGLES_KHR;
		accelerationStructureGeometry.geometry.triangles.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_TRIANGLES_DATA_KHR;
		accelerationStructureGeometry.geometry.triangles.vertexFormat = VK_FORMAT_R32G32B32_SFLOAT;
		accelerationStructureGeometry.geometry.triangles.vertexData = vertexBufferDeviceAddress;
		accelerationStructureGeometry.geometry.triangles.maxVertex = 3;
		accelerationStructureGeometry.geometry.triangles.vertexStride = sizeof(Vertex);
		accelerationStructureGeometry.geometry.triangles.indexType = VK_INDEX_TYPE_UINT32;
		accelerationStructureGeometry.geometry.triangles.indexData = indexBufferDeviceAddress;
		accelerationStructureGeometry.geometry.triangles.transformData.deviceAddress = 0;
		accelerationStructureGeometry.geometry.triangles.transformData.hostAddress = nullptr;
		accelerationStructureGeometry.geometry.triangles.transformData = transformBufferDeviceAddress;
		
		// Get size info
		VkAccelerationStructureBuildGeometryInfoKHR accelerationStructureBuildGeometryInfo{};
		accelerationStructureBuildGeometryInfo.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_BUILD_GEOMETRY_INFO_KHR;
		accelerationStructureBuildGeometryInfo.type = VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR;
		accelerationStructureBuildGeometryInfo.flags = VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR;
		accelerationStructureBuildGeometryInfo.geometryCount = 1;
		accelerationStructureBuildGeometryInfo.pGeometries = &accelerationStructureGeometry;
		
		const uint32_t numTriangles = static_cast<uint32_t>(indices.size() / 3);

		VkAccelerationStructureBuildSizesInfoKHR accelerationStructureBuildSizesInfo{};
		accelerationStructureBuildSizesInfo.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_BUILD_SIZES_INFO_KHR;
		vkGetAccelerationStructureBuildSizesKHR(
			device,
			VK_ACCELERATION_STRUCTURE_BUILD_TYPE_DEVICE_KHR,
			&accelerationStructureBuildGeometryInfo,
			&numTriangles,
			&accelerationStructureBuildSizesInfo);

		createAccelerationStructureBuffer(bottomLevelAS, accelerationStructureBuildSizesInfo);

		VkAccelerationStructureCreateInfoKHR accelerationStructureCreateInfo{};
		accelerationStructureCreateInfo.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_CREATE_INFO_KHR;
		accelerationStructureCreateInfo.buffer = bottomLevelAS.buffer;
		accelerationStructureCreateInfo.size = accelerationStructureBuildSizesInfo.accelerationStructureSize;
		accelerationStructureCreateInfo.type = VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR;
		vkCreateAccelerationStructureKHR(device, &accelerationStructureCreateInfo, nullptr, &bottomLevelAS.handle);

		// Create a small scratch buffer used during build of the bottom level acceleration structure
		ScratchBuffer scratchBuffer = createScratchBuffer(accelerationStructureBuildSizesInfo.buildScratchSize);

		VkAccelerationStructureBuildGeometryInfoKHR accelerationBuildGeometryInfo{};
		accelerationBuildGeometryInfo.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_BUILD_GEOMETRY_INFO_KHR;
		accelerationBuildGeometryInfo.type = VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR;
		accelerationBuildGeometryInfo.flags = VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR;
		accelerationBuildGeometryInfo.mode = VK_BUILD_ACCELERATION_STRUCTURE_MODE_BUILD_KHR;
		accelerationBuildGeometryInfo.dstAccelerationStructure = bottomLevelAS.handle;
		accelerationBuildGeometryInfo.geometryCount = 1;
		accelerationBuildGeometryInfo.pGeometries = &accelerationStructureGeometry;
		accelerationBuildGeometryInfo.scratchData.deviceAddress = scratchBuffer.deviceAddress;

		VkAccelerationStructureBuildRangeInfoKHR accelerationStructureBuildRangeInfo{};
		accelerationStructureBuildRangeInfo.primitiveCount = numTriangles;
		accelerationStructureBuildRangeInfo.primitiveOffset = 0;
		accelerationStructureBuildRangeInfo.firstVertex = 0;
		accelerationStructureBuildRangeInfo.transformOffset = 0;
		std::vector<VkAccelerationStructureBuildRangeInfoKHR*> accelerationBuildStructureRangeInfos = { &accelerationStructureBuildRangeInfo };

		// Build the acceleration structure on the device via a one-time command buffer submission
		// Some implementations may support acceleration structure building on the host (VkPhysicalDeviceAccelerationStructureFeaturesKHR->accelerationStructureHostCommands), but we prefer device builds
		VkCommandBuffer commandBuffer = vulkanDevice->createCommandBuffer(VK_COMMAND_BUFFER_LEVEL_PRIMARY, true);
		vkCmdBuildAccelerationStructuresKHR(
			commandBuffer,
			1,
			&accelerationBuildGeometryInfo,
			accelerationBuildStructureRangeInfos.data());
		vulkanDevice->flushCommandBuffer(commandBuffer, queue);

		VkAccelerationStructureDeviceAddressInfoKHR accelerationDeviceAddressInfo{};
		accelerationDeviceAddressInfo.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_DEVICE_ADDRESS_INFO_KHR;
		accelerationDeviceAddressInfo.accelerationStructure = bottomLevelAS.handle;
		bottomLevelAS.deviceAddress = vkGetAccelerationStructureDeviceAddressKHR(device, &accelerationDeviceAddressInfo);

		deleteScratchBuffer(scratchBuffer);
	}

	/*
		The top level acceleration structure contains the scene's object instances
	*/
	void createTopLevelAccelerationStructure()
	{
		VkTransformMatrixKHR transformMatrix = {
			1.0f, 0.0f, 0.0f, 0.0f,
			0.0f, 1.0f, 0.0f, 0.0f,
			0.0f, 0.0f, 1.0f, 0.0f };

		VkAccelerationStructureInstanceKHR instance{};
		instance.transform = transformMatrix;
		instance.instanceCustomIndex = 0;
		instance.mask = 0xFF;
		instance.instanceShaderBindingTableRecordOffset = 0;
		instance.flags = VK_GEOMETRY_INSTANCE_TRIANGLE_FACING_CULL_DISABLE_BIT_KHR;
		instance.accelerationStructureReference = bottomLevelAS.deviceAddress;

		// Buffer for instance data
		vks::Buffer instancesBuffer;
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT | VK_BUFFER_USAGE_ACCELERATION_STRUCTURE_BUILD_INPUT_READ_ONLY_BIT_KHR,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&instancesBuffer,
			sizeof(VkAccelerationStructureInstanceKHR),
			&instance));

		VkDeviceOrHostAddressConstKHR instanceDataDeviceAddress{};
		instanceDataDeviceAddress.deviceAddress = getBufferDeviceAddress(instancesBuffer.buffer);

		VkAccelerationStructureGeometryKHR accelerationStructureGeometry{};
		accelerationStructureGeometry.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_KHR;
		accelerationStructureGeometry.geometryType = VK_GEOMETRY_TYPE_INSTANCES_KHR;
		accelerationStructureGeometry.flags = VK_GEOMETRY_OPAQUE_BIT_KHR;
		accelerationStructureGeometry.geometry.instances.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_INSTANCES_DATA_KHR;
		accelerationStructureGeometry.geometry.instances.arrayOfPointers = VK_FALSE;
		accelerationStructureGeometry.geometry.instances.data = instanceDataDeviceAddress;

		// Get size info
		/*
		The pSrcAccelerationStructure, dstAccelerationStructure, and mode members of pBuildInfo are ignored. Any VkDeviceOrHostAddressKHR members of pBuildInfo are ignored by this command, except that the hostAddress member of VkAccelerationStructureGeometryTrianglesDataKHR::transformData will be examined to check if it is NULL.*
		*/
		VkAccelerationStructureBuildGeometryInfoKHR accelerationStructureBuildGeometryInfo{};
		accelerationStructureBuildGeometryInfo.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_BUILD_GEOMETRY_INFO_KHR;
		accelerationStructureBuildGeometryInfo.type = VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR;
		accelerationStructureBuildGeometryInfo.flags = VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR;
		accelerationStructureBuildGeometryInfo.geometryCount = 1;
		accelerationStructureBuildGeometryInfo.pGeometries = &accelerationStructureGeometry;

		uint32_t primitive_count = 1;

		VkAccelerationStructureBuildSizesInfoKHR accelerationStructureBuildSizesInfo{};
		accelerationStructureBuildSizesInfo.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_BUILD_SIZES_INFO_KHR;
		vkGetAccelerationStructureBuildSizesKHR(
			device, 
			VK_ACCELERATION_STRUCTURE_BUILD_TYPE_DEVICE_KHR,
			&accelerationStructureBuildGeometryInfo,
			&primitive_count,
			&accelerationStructureBuildSizesInfo);

		createAccelerationStructureBuffer(topLevelAS, accelerationStructureBuildSizesInfo);

		VkAccelerationStructureCreateInfoKHR accelerationStructureCreateInfo{};
		accelerationStructureCreateInfo.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_CREATE_INFO_KHR;
		accelerationStructureCreateInfo.buffer = topLevelAS.buffer;
		accelerationStructureCreateInfo.size = accelerationStructureBuildSizesInfo.accelerationStructureSize;
		accelerationStructureCreateInfo.type = VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR;
		vkCreateAccelerationStructureKHR(device, &accelerationStructureCreateInfo, nullptr, &topLevelAS.handle);

		// Create a small scratch buffer used during build of the top level acceleration structure
		ScratchBuffer scratchBuffer = createScratchBuffer(accelerationStructureBuildSizesInfo.buildScratchSize);

		VkAccelerationStructureBuildGeometryInfoKHR accelerationBuildGeometryInfo{};
		accelerationBuildGeometryInfo.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_BUILD_GEOMETRY_INFO_KHR;
		accelerationBuildGeometryInfo.type = VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR;
		accelerationBuildGeometryInfo.flags = VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR;
		accelerationBuildGeometryInfo.mode = VK_BUILD_ACCELERATION_STRUCTURE_MODE_BUILD_KHR;
		accelerationBuildGeometryInfo.dstAccelerationStructure = topLevelAS.handle;
		accelerationBuildGeometryInfo.geometryCount = 1;
		accelerationBuildGeometryInfo.pGeometries = &accelerationStructureGeometry;
		accelerationBuildGeometryInfo.scratchData.deviceAddress = scratchBuffer.deviceAddress;

		VkAccelerationStructureBuildRangeInfoKHR accelerationStructureBuildRangeInfo{};
		accelerationStructureBuildRangeInfo.primitiveCount = 1;
		accelerationStructureBuildRangeInfo.primitiveOffset = 0;
		accelerationStructureBuildRangeInfo.firstVertex = 0;
		accelerationStructureBuildRangeInfo.transformOffset = 0;
		std::vector<VkAccelerationStructureBuildRangeInfoKHR*> accelerationBuildStructureRangeInfos = { &accelerationStructureBuildRangeInfo };

		// Build the acceleration structure on the device via a one-time command buffer submission
		// Some implementations may support acceleration structure building on the host (VkPhysicalDeviceAccelerationStructureFeaturesKHR->accelerationStructureHostCommands), but we prefer device builds
		VkCommandBuffer commandBuffer = vulkanDevice->createCommandBuffer(VK_COMMAND_BUFFER_LEVEL_PRIMARY, true);
		vkCmdBuildAccelerationStructuresKHR(
			commandBuffer,
			1,
			&accelerationBuildGeometryInfo,
			accelerationBuildStructureRangeInfos.data());
		vulkanDevice->flushCommandBuffer(commandBuffer, queue);

		VkAccelerationStructureDeviceAddressInfoKHR accelerationDeviceAddressInfo{};
		accelerationDeviceAddressInfo.sType = VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_DEVICE_ADDRESS_INFO_KHR;
		accelerationDeviceAddressInfo.accelerationStructure = topLevelAS.handle;
		topLevelAS.deviceAddress = vkGetAccelerationStructureDeviceAddressKHR(device, &accelerationDeviceAddressInfo);

		deleteScratchBuffer(scratchBuffer);
		instancesBuffer.destroy();
	}

	/*
		Create the Shader Binding Tables that binds the programs and top-level acceleration structure

		SBT Layout used in this sample:

			/-----------\
			| raygen    |
			|-----------|
			| miss      |
			|-----------|
			| hit       |
			\-----------/

	*/
	void createShaderBindingTables() {
		const uint32_t handleSize = rayTracingPipelineProperties.shaderGroupHandleSize;
		const uint32_t handleSizeAligned = vks::tools::alignedSize(rayTracingPipelineProperties.shaderGroupHandleSize, rayTracingPipelineProperties.shaderGroupHandleAlignment);
		const uint32_t groupCount = static_cast<uint32_t>(shaderGroups.size());
		const uint32_t sbtSize = groupCount * handleSizeAligned;

		std::vector<uint8_t> shaderHandleStorage(sbtSize);
		VK_CHECK_RESULT(vkGetRayTracingShaderGroupHandlesKHR(device, pipeline, 0, groupCount, sbtSize, shaderHandleStorage.data()));

		createShaderBindingTable(shaderBindingTables.raygen, 1);
		createShaderBindingTable(shaderBindingTables.miss, 1);
		createShaderBindingTable(shaderBindingTables.hit, 1);

		// Copy handles
		memcpy(shaderBindingTables.raygen.mapped, shaderHandleStorage.data(), handleSize);
		memcpy(shaderBindingTables.miss.mapped, shaderHandleStorage.data() + handleSizeAligned, handleSize);
		memcpy(shaderBindingTables.hit.mapped, shaderHandleStorage.data() + handleSizeAligned * 2, handleSize);
	}

	/*
		Create the descriptor sets used for the ray tracing dispatch
	*/
	void createDescriptorSets()
	{
		std::vector<VkDescriptorPoolSize> poolSizes = {
			{ VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_KHR, 1 },
			{ VK_DESCRIPTOR_TYPE_STORAGE_IMAGE, 1 },
			{ VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 1 },
			{ VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1 }
		};
		VkDescriptorPoolCreateInfo descriptorPoolCreateInfo = vks::initializers::descriptorPoolCreateInfo(poolSizes, 1);
		VK_CHECK_RESULT(vkCreateDescriptorPool(device, &descriptorPoolCreateInfo, nullptr, &descriptorPool));

		VkDescriptorSetAllocateInfo descriptorSetAllocateInfo = vks::initializers::descriptorSetAllocateInfo(descriptorPool, &descriptorSetLayout, 1);
		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &descriptorSetAllocateInfo, &descriptorSet));

		VkWriteDescriptorSetAccelerationStructureKHR descriptorAccelerationStructureInfo = vks::initializers::writeDescriptorSetAccelerationStructureKHR();
		descriptorAccelerationStructureInfo.accelerationStructureCount = 1;
		descriptorAccelerationStructureInfo.pAccelerationStructures = &topLevelAS.handle;

		VkWriteDescriptorSet accelerationStructureWrite{};
		accelerationStructureWrite.sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
		// The specialized acceleration structure descriptor has to be chained
		accelerationStructureWrite.pNext = &descriptorAccelerationStructureInfo;
		accelerationStructureWrite.dstSet = descriptorSet;
		accelerationStructureWrite.dstBinding = 0;
		accelerationStructureWrite.descriptorCount = 1;
		accelerationStructureWrite.descriptorType = VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_KHR;

		VkDescriptorImageInfo storageImageDescriptor{ VK_NULL_HANDLE, storageImage.view, VK_IMAGE_LAYOUT_GENERAL };

		std::vector<VkWriteDescriptorSet> writeDescriptorSets = {
			// Binding 0: Top level acceleration structure
			accelerationStructureWrite,
			// Binding 1: Ray tracing result image
			vks::initializers::writeDescriptorSet(descriptorSet, VK_DESCRIPTOR_TYPE_STORAGE_IMAGE, 1, &storageImageDescriptor),
			// Binding 2: Uniform data
			vks::initializers::writeDescriptorSet(descriptorSet, VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 2, &ubo.descriptor),
			// Binding 3: Texture image
			vks::initializers::writeDescriptorSet(descriptorSet, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 3, &texture.descriptor),
		};
		vkUpdateDescriptorSets(device, static_cast<uint32_t>(writeDescriptorSets.size()), writeDescriptorSets.data(), 0, VK_NULL_HANDLE);
	}

	/*
		Create our ray tracing pipeline
	*/
	void createRayTracingPipeline()
	{
		std::vector<VkDescriptorSetLayoutBinding> setLayoutBindings = {
			// Binding 0: Top level acceleration structure
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_KHR, VK_SHADER_STAGE_RAYGEN_BIT_KHR | VK_SHADER_STAGE_CLOSEST_HIT_BIT_KHR, 0),
			// Binding 1: Ray tracing result image
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_STORAGE_IMAGE, VK_SHADER_STAGE_RAYGEN_BIT_KHR, 1),
			// Binding 2: Uniform buffer
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, VK_SHADER_STAGE_RAYGEN_BIT_KHR | VK_SHADER_STAGE_CLOSEST_HIT_BIT_KHR | VK_SHADER_STAGE_MISS_BIT_KHR, 2),
			// Binding 3: Texture image
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, VK_SHADER_STAGE_CLOSEST_HIT_BIT_KHR | VK_SHADER_STAGE_ANY_HIT_BIT_KHR, 3)
		};

		VkDescriptorSetLayoutCreateInfo descriptorSetLayoutCI = vks::initializers::descriptorSetLayoutCreateInfo(setLayoutBindings);
		VK_CHECK_RESULT(vkCreateDescriptorSetLayout(device, &descriptorSetLayoutCI, nullptr, &descriptorSetLayout));

		// We pass buffer references for vertex and index buffers via push constants
		VkPushConstantRange pushConstantRange{};
		pushConstantRange.stageFlags = VK_SHADER_STAGE_CLOSEST_HIT_BIT_KHR | VK_SHADER_STAGE_ANY_HIT_BIT_KHR;
		pushConstantRange.offset = 0;
		pushConstantRange.size = sizeof(uint64_t) * 2;

		VkPipelineLayoutCreateInfo pipelineLayoutCI = vks::initializers::pipelineLayoutCreateInfo(&descriptorSetLayout, 1);
		pipelineLayoutCI.pPushConstantRanges = &pushConstantRange;
		pipelineLayoutCI.pushConstantRangeCount = 1;
		VK_CHECK_RESULT(vkCreatePipelineLayout(device, &pipelineLayoutCI, nullptr, &pipelineLayout));

		/*
			Setup ray tracing shader groups
		*/
		std::vector<VkPipelineShaderStageCreateInfo> shaderStages;

		// Ray generation group
		{
			shaderStages.push_back(loadShader(getShadersPath() + "raytracingtextures/raygen.rgen.spv", VK_SHADER_STAGE_RAYGEN_BIT_KHR));
			VkRayTracingShaderGroupCreateInfoKHR shaderGroup{};
			shaderGroup.sType = VK_STRUCTURE_TYPE_RAY_TRACING_SHADER_GROUP_CREATE_INFO_KHR;
			shaderGroup.type = VK_RAY_TRACING_SHADER_GROUP_TYPE_GENERAL_KHR;
			shaderGroup.generalShader = static_cast<uint32_t>(shaderStages.size()) - 1;
			shaderGroup.closestHitShader = VK_SHADER_UNUSED_KHR;
			shaderGroup.anyHitShader = VK_SHADER_UNUSED_KHR;
			shaderGroup.intersectionShader = VK_SHADER_UNUSED_KHR;
			shaderGroups.push_back(shaderGroup);
		}

		// Miss group
		{
			shaderStages.push_back(loadShader(getShadersPath() + "raytracingtextures/miss.rmiss.spv", VK_SHADER_STAGE_MISS_BIT_KHR));
			VkRayTracingShaderGroupCreateInfoKHR shaderGroup{};
			shaderGroup.sType = VK_STRUCTURE_TYPE_RAY_TRACING_SHADER_GROUP_CREATE_INFO_KHR;
			shaderGroup.type = VK_RAY_TRACING_SHADER_GROUP_TYPE_GENERAL_KHR;
			shaderGroup.generalShader = static_cast<uint32_t>(shaderStages.size()) - 1;
			shaderGroup.closestHitShader = VK_SHADER_UNUSED_KHR;
			shaderGroup.anyHitShader = VK_SHADER_UNUSED_KHR;
			shaderGroup.intersectionShader = VK_SHADER_UNUSED_KHR;
			shaderGroups.push_back(shaderGroup);
		}

		// Closest hit group for doing texture lookups
		{
			shaderStages.push_back(loadShader(getShadersPath() + "raytracingtextures/closesthit.rchit.spv", VK_SHADER_STAGE_CLOSEST_HIT_BIT_KHR));
			VkRayTracingShaderGroupCreateInfoKHR shaderGroup{};
			shaderGroup.sType = VK_STRUCTURE_TYPE_RAY_TRACING_SHADER_GROUP_CREATE_INFO_KHR;
			shaderGroup.type = VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_KHR;
			shaderGroup.generalShader = VK_SHADER_UNUSED_KHR;
			shaderGroup.closestHitShader = static_cast<uint32_t>(shaderStages.size()) - 1;
			shaderGroup.intersectionShader = VK_SHADER_UNUSED_KHR;
			// This group also uses an anyhit shader for doing transparency (see anyhit.rahit for details)
			shaderStages.push_back(loadShader(getShadersPath() + "raytracingtextures/anyhit.rahit.spv", VK_SHADER_STAGE_ANY_HIT_BIT_KHR));
			shaderGroup.anyHitShader = static_cast<uint32_t>(shaderStages.size()) - 1;
			shaderGroups.push_back(shaderGroup);
		}

		/*
			Create the ray tracing pipeline
		*/
		VkRayTracingPipelineCreateInfoKHR rayTracingPipelineCI{};
		rayTracingPipelineCI.sType = VK_STRUCTURE_TYPE_RAY_TRACING_PIPELINE_CREATE_INFO_KHR;
		rayTracingPipelineCI.stageCount = static_cast<uint32_t>(shaderStages.size());
		rayTracingPipelineCI.pStages = shaderStages.data();
		rayTracingPipelineCI.groupCount = static_cast<uint32_t>(shaderGroups.size());
		rayTracingPipelineCI.pGroups = shaderGroups.data();
		rayTracingPipelineCI.maxPipelineRayRecursionDepth = 1;
		rayTracingPipelineCI.layout = pipelineLayout;
		VK_CHECK_RESULT(vkCreateRayTracingPipelinesKHR(device, VK_NULL_HANDLE, VK_NULL_HANDLE, 1, &rayTracingPipelineCI, nullptr, &pipeline));
	}

	/*
		Create the uniform buffer used to pass matrices to the ray tracing ray generation shader
	*/
	void createUniformBuffer()
	{
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&ubo,
			sizeof(uniformData),
			&uniformData));
		VK_CHECK_RESULT(ubo.map());

		updateUniformBuffers();
	}

	/*
		If the window has been resized, we need to recreate the storage image and it's descriptor
	*/
	void handleResize()
	{
		// Recreate image
		createStorageImage(swapChain.colorFormat, { width, height, 1 });
		// Update descriptor
		VkDescriptorImageInfo storageImageDescriptor{ VK_NULL_HANDLE, storageImage.view, VK_IMAGE_LAYOUT_GENERAL };
		VkWriteDescriptorSet resultImageWrite = vks::initializers::writeDescriptorSet(descriptorSet, VK_DESCRIPTOR_TYPE_STORAGE_IMAGE, 1, &storageImageDescriptor);
		vkUpdateDescriptorSets(device, 1, &resultImageWrite, 0, VK_NULL_HANDLE);
		resized = false;
	}

	/*
		Command buffer generation
	*/
	void buildCommandBuffers()
	{
		if (resized)
		{
			handleResize();
		}

		VkCommandBufferBeginInfo cmdBufInfo = vks::initializers::commandBufferBeginInfo();

		VkImageSubresourceRange subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };

		for (int32_t i = 0; i < drawCmdBuffers.size(); ++i)
		{
			VK_CHECK_RESULT(vkBeginCommandBuffer(drawCmdBuffers[i], &cmdBufInfo));

			/*
				Dispatch the ray tracing commands
			*/
			vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_RAY_TRACING_KHR, pipeline);
			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_RAY_TRACING_KHR, pipelineLayout, 0, 1, &descriptorSet, 0, 0);

			struct BufferReferences {
				uint64_t vertices;
				uint64_t indices;
			} bufferReferences; 

			bufferReferences.vertices = getBufferDeviceAddress(vertexBuffer.buffer);
			bufferReferences.indices = getBufferDeviceAddress(indexBuffer.buffer);

			// We set the buffer references for the mesh to be rendered using a push constant
			// If we wanted to render multiple objecets this would make it very easy to access their vertex and index buffers
			vkCmdPushConstants(drawCmdBuffers[i], pipelineLayout, VK_SHADER_STAGE_CLOSEST_HIT_BIT_KHR | VK_SHADER_STAGE_ANY_HIT_BIT_KHR, 0, sizeof(uint64_t) * 2, &bufferReferences);

			VkStridedDeviceAddressRegionKHR emptySbtEntry = {};
			vkCmdTraceRaysKHR(
				drawCmdBuffers[i],
				&shaderBindingTables.raygen.stridedDeviceAddressRegion,
				&shaderBindingTables.miss.stridedDeviceAddressRegion,
				&shaderBindingTables.hit.stridedDeviceAddressRegion,
				&emptySbtEntry,
				width,
				height,
				1);

			/*
				Copy ray tracing output to swap chain image
			*/

			// Prepare current swap chain image as transfer destination
			vks::tools::setImageLayout(
				drawCmdBuffers[i],
				swapChain.images[i],
				VK_IMAGE_LAYOUT_UNDEFINED,
				VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
				subresourceRange);

			// Prepare ray tracing output image as transfer source
			vks::tools::setImageLayout(
				drawCmdBuffers[i],
				storageImage.image,
				VK_IMAGE_LAYOUT_GENERAL,
				VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
				subresourceRange);

			VkImageCopy copyRegion{};
			copyRegion.srcSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 1 };
			copyRegion.srcOffset = { 0, 0, 0 };
			copyRegion.dstSubresource = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0, 1 };
			copyRegion.dstOffset = { 0, 0, 0 };
			copyRegion.extent = { width, height, 1 };
			vkCmdCopyImage(drawCmdBuffers[i], storageImage.image, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL, swapChain.images[i], VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, 1, &copyRegion);

			// Transition swap chain image back for presentation
			vks::tools::setImageLayout(
				drawCmdBuffers[i],
				swapChain.images[i],
				VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
				VK_IMAGE_LAYOUT_PRESENT_SRC_KHR,
				subresourceRange);

			// Transition ray tracing output image back to general layout
			vks::tools::setImageLayout(
				drawCmdBuffers[i],
				storageImage.image,
				VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
				VK_IMAGE_LAYOUT_GENERAL,
				subresourceRange);

			drawUI(drawCmdBuffers[i], frameBuffers[i]);

			VK_CHECK_RESULT(vkEndCommandBuffer(drawCmdBuffers[i]));
		}
	}

	void updateUniformBuffers()
	{
		uniformData.projInverse = glm::inverse(camera.matrices.perspective);
		uniformData.viewInverse = glm::inverse(camera.matrices.view);
		memcpy(ubo.mapped, &uniformData, sizeof(uniformData));
	}

	void getEnabledFeatures()
	{
		// Enable features required for ray tracing using feature chaining via pNext		
		enabledBufferDeviceAddresFeatures.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BUFFER_DEVICE_ADDRESS_FEATURES;
		enabledBufferDeviceAddresFeatures.bufferDeviceAddress = VK_TRUE;

		enabledRayTracingPipelineFeatures.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RAY_TRACING_PIPELINE_FEATURES_KHR;
		enabledRayTracingPipelineFeatures.rayTracingPipeline = VK_TRUE;
		enabledRayTracingPipelineFeatures.pNext = &enabledBufferDeviceAddresFeatures;

		enabledAccelerationStructureFeatures.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ACCELERATION_STRUCTURE_FEATURES_KHR;
		enabledAccelerationStructureFeatures.accelerationStructure = VK_TRUE;
		enabledAccelerationStructureFeatures.pNext = &enabledRayTracingPipelineFeatures;

		deviceCreatepNextChain = &enabledAccelerationStructureFeatures;
	}

	void loadAssets()
	{
		texture.loadFromFile(getAssetPath() + "textures/gratefloor_rgba.ktx", VK_FORMAT_R8G8B8A8_UNORM, vulkanDevice, queue);
	}

	void prepare()
	{
		VulkanRaytracingSample::prepare();

		loadAssets();

		// Create the acceleration structures used to render the ray traced scene
		createBottomLevelAccelerationStructure();
		createTopLevelAccelerationStructure();

		createStorageImage(swapChain.colorFormat, { width, height, 1 });
		createUniformBuffer();
		createRayTracingPipeline();
		createShaderBindingTables();
		createDescriptorSets();
		buildCommandBuffers();
		prepared = true;
	}

	void draw()
	{
		VulkanExampleBase::prepareFrame();
		submitInfo.commandBufferCount = 1;
		submitInfo.pCommandBuffers = &drawCmdBuffers[currentBuffer];
		VK_CHECK_RESULT(vkQueueSubmit(queue, 1, &submitInfo, VK_NULL_HANDLE));
		VulkanExampleBase::submitFrame();
	}

	virtual void render()
	{
		if (!prepared)
			return;
		draw();
		if (camera.updated)
			updateUniformBuffers();
	}
};

VULKAN_EXAMPLE_MAIN()