/*
* Vulkan Example - Physical based rendering with image based lighting
*
* Note: Requires the separate asset pack (see data/README.md)
*
* Copyright (C) 2016-2017 by Sascha Willems - www.saschawillems.de
*
* This code is licensed under the MIT license (MIT) (http://opensource.org/licenses/MIT)
*/

// For reference see http://blog.selfshadow.com/publications/s2013-shading-course/karis/s2013_pbs_epic_notes_v2.pdf

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <vector>
#include <chrono>

#define GLM_FORCE_RADIANS
#define GLM_FORCE_DEPTH_ZERO_TO_ONE
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>

#include <gli/gli.hpp>

#include <vulkan/vulkan.h>
#include "vulkanexamplebase.h"
#include "VulkanBuffer.hpp"
#include "VulkanTexture.hpp"
#include "VulkanModel.hpp"

#define ENABLE_VALIDATION false
#define GRID_DIM 7

struct Material {
	// Parameter block used as push constant block
	struct PushBlock {
		float roughness = 0.0f;
		float metallic = 0.0f;
		float specular = 0.0f;
		float r, g, b;
	} params;
	std::string name;
	Material() {};
	Material(std::string n, glm::vec3 c) : name(n) {
		params.r = c.r;
		params.g = c.g;
		params.b = c.b;
	};
};

class VulkanExample : public VulkanExampleBase
{
public:
	bool displaySkybox = true;

	struct Textures {
		vks::TextureCubeMap environmentCube;
		// Generated at runtime
		vks::Texture2D lutBrdf;
		vks::TextureCubeMap irradianceCube;
		vks::TextureCubeMap prefilteredCube;
	} textures;

	// Vertex layout for the models
	vks::VertexLayout vertexLayout = vks::VertexLayout({
		vks::VERTEX_COMPONENT_POSITION,
		vks::VERTEX_COMPONENT_NORMAL,
		vks::VERTEX_COMPONENT_UV,
	});

	struct Meshes {
		vks::Model skybox;
		std::vector<vks::Model> objects;
		int32_t objectIndex = 0;
	} models;

	struct {
		vks::Buffer object;
		vks::Buffer skybox;
		vks::Buffer params;
	} uniformBuffers;

	struct UBOMatrices {
		glm::mat4 projection;
		glm::mat4 model;
		glm::mat4 view;
		glm::vec3 camPos;
	} uboMatrices;

	struct UBOParams {
		glm::vec4 lights[4];
		float exposure = 4.5f;
		float gamma = 2.2f;
	} uboParams;

	struct {
		VkPipeline skybox;
		VkPipeline pbr;
	} pipelines;

	struct {
		VkDescriptorSet object;
		VkDescriptorSet skybox;
	} descriptorSets;

	VkPipelineLayout pipelineLayout;
	VkDescriptorSetLayout descriptorSetLayout;

	// Default materials to select from
	std::vector<Material> materials;
	int32_t materialIndex = 0;

	std::vector<std::string> materialNames;
	std::vector<std::string> objectNames;

	VulkanExample() : VulkanExampleBase(ENABLE_VALIDATION)
	{
		title = "PBR with image based lighting";

		camera.type = Camera::CameraType::firstperson;
		camera.movementSpeed = 4.0f;
		camera.setPerspective(60.0f, (float)width / (float)height, 0.1f, 256.0f);
		camera.rotationSpeed = 0.25f;

		camera.setRotation({ -3.75f, 180.0f, 0.0f });
		camera.setPosition({ 0.55f, 0.85f, 12.0f });

		// Setup some default materials (source: https://seblagarde.wordpress.com/2011/08/17/feeding-a-physical-based-lighting-mode/)
		materials.push_back(Material("Gold", glm::vec3(1.0f, 0.765557f, 0.336057f)));
		materials.push_back(Material("Copper", glm::vec3(0.955008f, 0.637427f, 0.538163f)));
		materials.push_back(Material("Chromium", glm::vec3(0.549585f, 0.556114f, 0.554256f)));
		materials.push_back(Material("Nickel", glm::vec3(0.659777f, 0.608679f, 0.525649f)));
		materials.push_back(Material("Titanium", glm::vec3(0.541931f, 0.496791f, 0.449419f)));
		materials.push_back(Material("Cobalt", glm::vec3(0.662124f, 0.654864f, 0.633732f)));
		materials.push_back(Material("Platinum", glm::vec3(0.672411f, 0.637331f, 0.585456f)));
		// Testing materials
		materials.push_back(Material("White", glm::vec3(1.0f)));
		materials.push_back(Material("Dark", glm::vec3(0.1f)));
		materials.push_back(Material("Black", glm::vec3(0.0f)));
		materials.push_back(Material("Red", glm::vec3(1.0f, 0.0f, 0.0f)));
		materials.push_back(Material("Blue", glm::vec3(0.0f, 0.0f, 1.0f)));

		settings.overlay = true;

		for (auto material : materials) {
			materialNames.push_back(material.name);
		}
		objectNames = { "Sphere", "Teapot", "Torusknot", "Venus" };

		materialIndex = 9;
	}

	~VulkanExample()
	{
		vkDestroyPipeline(device, pipelines.skybox, nullptr);
		vkDestroyPipeline(device, pipelines.pbr, nullptr);

		vkDestroyPipelineLayout(device, pipelineLayout, nullptr);
		vkDestroyDescriptorSetLayout(device, descriptorSetLayout, nullptr);

		for (auto& model : models.objects) {
			model.destroy();
		}
		models.skybox.destroy();

		uniformBuffers.object.destroy();
		uniformBuffers.skybox.destroy();
		uniformBuffers.params.destroy();
		
		textures.environmentCube.destroy();
		textures.irradianceCube.destroy();
		textures.prefilteredCube.destroy();
		textures.lutBrdf.destroy();
	}

	virtual void getEnabledFeatures()
	{
		if (deviceFeatures.samplerAnisotropy) {
			enabledFeatures.samplerAnisotropy = VK_TRUE;
		}
	}

	void buildCommandBuffers()
	{
		VkCommandBufferBeginInfo cmdBufInfo = vks::initializers::commandBufferBeginInfo();

		VkClearValue clearValues[2];
		clearValues[0].color = { { 0.1f, 0.1f, 0.1f, 1.0f } };
		clearValues[1].depthStencil = { 1.0f, 0 };

		VkRenderPassBeginInfo renderPassBeginInfo = vks::initializers::renderPassBeginInfo();
		renderPassBeginInfo.renderPass = renderPass;
		renderPassBeginInfo.renderArea.offset.x = 0;
		renderPassBeginInfo.renderArea.offset.y = 0;
		renderPassBeginInfo.renderArea.extent.width = width;
		renderPassBeginInfo.renderArea.extent.height = height;
		renderPassBeginInfo.clearValueCount = 2;
		renderPassBeginInfo.pClearValues = clearValues;

		for (size_t i = 0; i < drawCmdBuffers.size(); ++i)
		{
			// Set target frame buffer
			renderPassBeginInfo.framebuffer = frameBuffers[i];

			VK_CHECK_RESULT(vkBeginCommandBuffer(drawCmdBuffers[i], &cmdBufInfo));

			vkCmdBeginRenderPass(drawCmdBuffers[i], &renderPassBeginInfo, VK_SUBPASS_CONTENTS_INLINE);

			VkViewport viewport = vks::initializers::viewport((float)width,	(float)height, 0.0f, 1.0f);
			vkCmdSetViewport(drawCmdBuffers[i], 0, 1, &viewport);

			VkRect2D scissor = vks::initializers::rect2D(width,	height,	0, 0);
			vkCmdSetScissor(drawCmdBuffers[i], 0, 1, &scissor);

			VkDeviceSize offsets[1] = { 0 };

			// Skybox
			if (displaySkybox)
			{
				vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSets.skybox, 0, NULL);
				vkCmdBindVertexBuffers(drawCmdBuffers[i], 0, 1, &models.skybox.vertices.buffer, offsets);
				vkCmdBindIndexBuffer(drawCmdBuffers[i], models.skybox.indices.buffer, 0, VK_INDEX_TYPE_UINT32);
				vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelines.skybox);
				vkCmdDrawIndexed(drawCmdBuffers[i], models.skybox.indexCount, 1, 0, 0, 0);
			}

			// Objects
			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSets.object, 0, NULL);
			vkCmdBindVertexBuffers(drawCmdBuffers[i], 0, 1, &models.objects[models.objectIndex].vertices.buffer, offsets);
			vkCmdBindIndexBuffer(drawCmdBuffers[i], models.objects[models.objectIndex].indices.buffer, 0, VK_INDEX_TYPE_UINT32);
			vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelines.pbr);

			Material mat = materials[materialIndex];

#define SINGLE_ROW 1	
#ifdef SINGLE_ROW
			uint32_t objcount = 10;
			for (uint32_t x = 0; x < objcount; x++) {
				glm::vec3 pos = glm::vec3(float(x - (objcount / 2.0f)) * 2.15f, 0.0f, 0.0f);
				mat.params.roughness = 1.0f-glm::clamp((float)x / (float)objcount, 0.005f, 1.0f);
				mat.params.metallic = glm::clamp((float)x / (float)objcount, 0.005f, 1.0f);
				vkCmdPushConstants(drawCmdBuffers[i], pipelineLayout, VK_SHADER_STAGE_VERTEX_BIT, 0, sizeof(glm::vec3), &pos);
				vkCmdPushConstants(drawCmdBuffers[i], pipelineLayout, VK_SHADER_STAGE_FRAGMENT_BIT, sizeof(glm::vec3), sizeof(Material::PushBlock), &mat);
				vkCmdDrawIndexed(drawCmdBuffers[i], models.objects[models.objectIndex].indexCount, 1, 0, 0, 0);
			}
#else
			for (uint32_t y = 0; y < GRID_DIM; y++) {
				mat.params.metallic = (float)y / (float)(GRID_DIM);
				for (uint32_t x = 0; x < GRID_DIM; x++) {
					glm::vec3 pos = glm::vec3(float(x - (GRID_DIM / 2.0f)) * 2.5f, 0.0f, float(y - (GRID_DIM / 2.0f)) * 2.5f);
					vkCmdPushConstants(drawCmdBuffers[i], pipelineLayout, VK_SHADER_STAGE_VERTEX_BIT, 0, sizeof(glm::vec3), &pos);
					mat.params.roughness = glm::clamp((float)x / (float)(GRID_DIM), 0.05f, 1.0f);
					vkCmdPushConstants(drawCmdBuffers[i], pipelineLayout, VK_SHADER_STAGE_FRAGMENT_BIT, sizeof(glm::vec3), sizeof(Material::PushBlock), &mat);
					vkCmdDrawIndexed(drawCmdBuffers[i], models.objects[models.objectIndex].indexCount, 1, 0, 0, 0);
				}
			}
#endif
			drawUI(drawCmdBuffers[i]);

			vkCmdEndRenderPass(drawCmdBuffers[i]);

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

	void loadAssets()
	{
		// Skybox
		models.skybox.loadFromFile(getAssetPath() + "models/cube.obj", vertexLayout, 1.0f, vulkanDevice, queue);
		// Objects
		std::vector<std::string> filenames = { "geosphere.obj", "teapot.dae", "torusknot.obj", "venus.fbx" };
		for (auto file : filenames) {
			vks::Model model;
			model.loadFromFile(getAssetPath() + "models/" + file, vertexLayout, 0.05f * (file == "venus.fbx" ? 3.0f : 1.0f), vulkanDevice, queue);
			models.objects.push_back(model);
		}
		textures.environmentCube.loadFromFile(getAssetPath() + "textures/hdr/pisa_cube.ktx", VK_FORMAT_R16G16B16A16_SFLOAT, vulkanDevice, queue);
	}

	void setupDescriptors()
	{
		// Descriptor Pool
		std::vector<VkDescriptorPoolSize> poolSizes = {
			vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 4),
			vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 6)
		};
		VkDescriptorPoolCreateInfo descriptorPoolInfo =	vks::initializers::descriptorPoolCreateInfo(poolSizes, 2);
		VK_CHECK_RESULT(vkCreateDescriptorPool(device, &descriptorPoolInfo, nullptr, &descriptorPool));

		// Descriptor set layout
		std::vector<VkDescriptorSetLayoutBinding> setLayoutBindings = {
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT, 0),
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, VK_SHADER_STAGE_FRAGMENT_BIT, 1),
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, VK_SHADER_STAGE_FRAGMENT_BIT, 2),
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, VK_SHADER_STAGE_FRAGMENT_BIT, 3),
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, VK_SHADER_STAGE_FRAGMENT_BIT, 4),
		};
		VkDescriptorSetLayoutCreateInfo descriptorLayout = 	vks::initializers::descriptorSetLayoutCreateInfo(setLayoutBindings);
		VK_CHECK_RESULT(vkCreateDescriptorSetLayout(device, &descriptorLayout, nullptr, &descriptorSetLayout));

		// Descriptor sets
		VkDescriptorSetAllocateInfo allocInfo = vks::initializers::descriptorSetAllocateInfo(descriptorPool, &descriptorSetLayout, 1);

		// Objects
		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &allocInfo, &descriptorSets.object));
		std::vector<VkWriteDescriptorSet> writeDescriptorSets = {
			vks::initializers::writeDescriptorSet(descriptorSets.object, VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 0, &uniformBuffers.object.descriptor),
			vks::initializers::writeDescriptorSet(descriptorSets.object, VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 1, &uniformBuffers.params.descriptor),
			vks::initializers::writeDescriptorSet(descriptorSets.object, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 2, &textures.irradianceCube.descriptor),
			vks::initializers::writeDescriptorSet(descriptorSets.object, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 3, &textures.lutBrdf.descriptor),
			vks::initializers::writeDescriptorSet(descriptorSets.object, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 4, &textures.prefilteredCube.descriptor),
		};
		vkUpdateDescriptorSets(device, static_cast<uint32_t>(writeDescriptorSets.size()), writeDescriptorSets.data(), 0, NULL);

		// Sky box
		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &allocInfo, &descriptorSets.skybox));
		writeDescriptorSets = {
			vks::initializers::writeDescriptorSet(descriptorSets.skybox, VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 0, &uniformBuffers.skybox.descriptor),
			vks::initializers::writeDescriptorSet(descriptorSets.skybox, VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 1, &uniformBuffers.params.descriptor),
			vks::initializers::writeDescriptorSet(descriptorSets.skybox, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 2, &textures.environmentCube.descriptor),
		};
		vkUpdateDescriptorSets(device, static_cast<uint32_t>(writeDescriptorSets.size()), writeDescriptorSets.data(), 0, NULL);
	}

	void preparePipelines()
	{
		VkPipelineInputAssemblyStateCreateInfo inputAssemblyState =
			vks::initializers::pipelineInputAssemblyStateCreateInfo(VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST, 0, VK_FALSE);

		VkPipelineRasterizationStateCreateInfo rasterizationState =
			vks::initializers::pipelineRasterizationStateCreateInfo(VK_POLYGON_MODE_FILL, VK_CULL_MODE_NONE, VK_FRONT_FACE_COUNTER_CLOCKWISE);

		VkPipelineColorBlendAttachmentState blendAttachmentState =
			vks::initializers::pipelineColorBlendAttachmentState(0xf, VK_FALSE);

		VkPipelineColorBlendStateCreateInfo colorBlendState =
			vks::initializers::pipelineColorBlendStateCreateInfo(1, &blendAttachmentState);

		VkPipelineDepthStencilStateCreateInfo depthStencilState =
			vks::initializers::pipelineDepthStencilStateCreateInfo(VK_FALSE, VK_FALSE, VK_COMPARE_OP_LESS_OR_EQUAL);

		VkPipelineViewportStateCreateInfo viewportState =
			vks::initializers::pipelineViewportStateCreateInfo(1, 1);

		VkPipelineMultisampleStateCreateInfo multisampleState =
			vks::initializers::pipelineMultisampleStateCreateInfo(VK_SAMPLE_COUNT_1_BIT);

		std::vector<VkDynamicState> dynamicStateEnables = {
			VK_DYNAMIC_STATE_VIEWPORT,
			VK_DYNAMIC_STATE_SCISSOR
		};
		VkPipelineDynamicStateCreateInfo dynamicState =
			vks::initializers::pipelineDynamicStateCreateInfo(dynamicStateEnables);

		// Pipeline layout
		VkPipelineLayoutCreateInfo pipelineLayoutCreateInfo = vks::initializers::pipelineLayoutCreateInfo(&descriptorSetLayout, 1);
		// Push constant ranges
		std::vector<VkPushConstantRange> pushConstantRanges = {
			vks::initializers::pushConstantRange(VK_SHADER_STAGE_VERTEX_BIT, sizeof(glm::vec3), 0),
			vks::initializers::pushConstantRange(VK_SHADER_STAGE_FRAGMENT_BIT, sizeof(Material::PushBlock), sizeof(glm::vec3)),
		};
		pipelineLayoutCreateInfo.pushConstantRangeCount = 2;
		pipelineLayoutCreateInfo.pPushConstantRanges = pushConstantRanges.data();
		VK_CHECK_RESULT(vkCreatePipelineLayout(device, &pipelineLayoutCreateInfo, nullptr, &pipelineLayout));

		// Pipelines
		VkGraphicsPipelineCreateInfo pipelineCreateInfo = vks::initializers::pipelineCreateInfo(pipelineLayout, renderPass);

		std::array<VkPipelineShaderStageCreateInfo, 2> shaderStages;

		pipelineCreateInfo.pInputAssemblyState = &inputAssemblyState;
		pipelineCreateInfo.pRasterizationState = &rasterizationState;
		pipelineCreateInfo.pColorBlendState = &colorBlendState;
		pipelineCreateInfo.pMultisampleState = &multisampleState;
		pipelineCreateInfo.pViewportState = &viewportState;
		pipelineCreateInfo.pDepthStencilState = &depthStencilState;
		pipelineCreateInfo.pDynamicState = &dynamicState;
		pipelineCreateInfo.stageCount = static_cast<uint32_t>(shaderStages.size());
		pipelineCreateInfo.pStages = shaderStages.data();

		// Vertex bindings an attributes
		// Binding description
		std::vector<VkVertexInputBindingDescription> vertexInputBindings = {
			vks::initializers::vertexInputBindingDescription(0, vertexLayout.stride(), VK_VERTEX_INPUT_RATE_VERTEX),
		};

		// Attribute descriptions
		std::vector<VkVertexInputAttributeDescription> vertexInputAttributes = {
			vks::initializers::vertexInputAttributeDescription(0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0),					// Position
			vks::initializers::vertexInputAttributeDescription(0, 1, VK_FORMAT_R32G32B32_SFLOAT, sizeof(float) * 3),	// Normal
			vks::initializers::vertexInputAttributeDescription(0, 2, VK_FORMAT_R32G32_SFLOAT, sizeof(float) * 6),		// UV
		};

		VkPipelineVertexInputStateCreateInfo vertexInputState = vks::initializers::pipelineVertexInputStateCreateInfo();
		vertexInputState.vertexBindingDescriptionCount = static_cast<uint32_t>(vertexInputBindings.size());
		vertexInputState.pVertexBindingDescriptions = vertexInputBindings.data();
		vertexInputState.vertexAttributeDescriptionCount = static_cast<uint32_t>(vertexInputAttributes.size());
		vertexInputState.pVertexAttributeDescriptions = vertexInputAttributes.data();

		pipelineCreateInfo.pVertexInputState = &vertexInputState;

		// Skybox pipeline (background cube)
		shaderStages[0] = loadShader(getAssetPath() +  "shaders/pbribl/skybox.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
		shaderStages[1] = loadShader(getAssetPath() +  "shaders/pbribl/skybox.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCreateInfo, nullptr, &pipelines.skybox));

		// PBR pipeline
		shaderStages[0] = loadShader(getAssetPath() +  "shaders/pbribl/pbribl.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
		shaderStages[1] = loadShader(getAssetPath() +  "shaders/pbribl/pbribl.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
		// Enable depth test and write
		depthStencilState.depthWriteEnable = VK_TRUE;
		depthStencilState.depthTestEnable = VK_TRUE;
		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCreateInfo, nullptr, &pipelines.pbr));
	}

	// Generate a BRDF integration map used as a look-up-table (stores roughness / NdotV)
	void generateBRDFLUT()
	{
		auto tStart = std::chrono::high_resolution_clock::now();

		const VkFormat format = VK_FORMAT_R16G16_SFLOAT;	// R16G16 is supported pretty much everywhere
		const int32_t dim = 512;

		// Image
		VkImageCreateInfo imageCI = vks::initializers::imageCreateInfo();
		imageCI.imageType = VK_IMAGE_TYPE_2D;
		imageCI.format = format;
		imageCI.extent.width = dim;
		imageCI.extent.height = dim;
		imageCI.extent.depth = 1;
		imageCI.mipLevels = 1;
		imageCI.arrayLayers = 1;
		imageCI.samples = VK_SAMPLE_COUNT_1_BIT;
		imageCI.tiling = VK_IMAGE_TILING_OPTIMAL;
		imageCI.usage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_SAMPLED_BIT;
		VK_CHECK_RESULT(vkCreateImage(device, &imageCI, nullptr, &textures.lutBrdf.image));
		VkMemoryAllocateInfo memAlloc = vks::initializers::memoryAllocateInfo();
		VkMemoryRequirements memReqs;
		vkGetImageMemoryRequirements(device, textures.lutBrdf.image, &memReqs);
		memAlloc.allocationSize = memReqs.size;
		memAlloc.memoryTypeIndex = vulkanDevice->getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
		VK_CHECK_RESULT(vkAllocateMemory(device, &memAlloc, nullptr, &textures.lutBrdf.deviceMemory));
		VK_CHECK_RESULT(vkBindImageMemory(device, textures.lutBrdf.image, textures.lutBrdf.deviceMemory, 0));
		// Image view
		VkImageViewCreateInfo viewCI = vks::initializers::imageViewCreateInfo();
		viewCI.viewType = VK_IMAGE_VIEW_TYPE_2D;
		viewCI.format = format;
		viewCI.subresourceRange = {};
		viewCI.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
		viewCI.subresourceRange.levelCount = 1;
		viewCI.subresourceRange.layerCount = 1;
		viewCI.image = textures.lutBrdf.image;
		VK_CHECK_RESULT(vkCreateImageView(device, &viewCI, nullptr, &textures.lutBrdf.view));
		// Sampler
		VkSamplerCreateInfo samplerCI = vks::initializers::samplerCreateInfo();
		samplerCI.magFilter = VK_FILTER_LINEAR;
		samplerCI.minFilter = VK_FILTER_LINEAR;
		samplerCI.mipmapMode = VK_SAMPLER_MIPMAP_MODE_LINEAR;
		samplerCI.addressModeU = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
		samplerCI.addressModeV = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
		samplerCI.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
		samplerCI.minLod = 0.0f;
		samplerCI.maxLod = 1.0f;
		samplerCI.borderColor = VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE;
		VK_CHECK_RESULT(vkCreateSampler(device, &samplerCI, nullptr, &textures.lutBrdf.sampler));

		textures.lutBrdf.descriptor.imageView = textures.lutBrdf.view;
		textures.lutBrdf.descriptor.sampler = textures.lutBrdf.sampler;
		textures.lutBrdf.descriptor.imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
		textures.lutBrdf.device = vulkanDevice;

		// FB, Att, RP, Pipe, etc.
		VkAttachmentDescription attDesc = {};
		// Color attachment
		attDesc.format = format;
		attDesc.samples = VK_SAMPLE_COUNT_1_BIT;
		attDesc.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
		attDesc.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
		attDesc.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
		attDesc.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
		attDesc.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
		attDesc.finalLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
		VkAttachmentReference colorReference = { 0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL };

		VkSubpassDescription subpassDescription = {};
		subpassDescription.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
		subpassDescription.colorAttachmentCount = 1;
		subpassDescription.pColorAttachments = &colorReference;

		// Use subpass dependencies for layout transitions
		std::array<VkSubpassDependency, 2> dependencies;
		dependencies[0].srcSubpass = VK_SUBPASS_EXTERNAL;
		dependencies[0].dstSubpass = 0;
		dependencies[0].srcStageMask = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
		dependencies[0].dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
		dependencies[0].srcAccessMask = VK_ACCESS_MEMORY_READ_BIT;
		dependencies[0].dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
		dependencies[0].dependencyFlags = VK_DEPENDENCY_BY_REGION_BIT;
		dependencies[1].srcSubpass = 0;
		dependencies[1].dstSubpass = VK_SUBPASS_EXTERNAL;
		dependencies[1].srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
		dependencies[1].dstStageMask = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
		dependencies[1].srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
		dependencies[1].dstAccessMask = VK_ACCESS_MEMORY_READ_BIT;
		dependencies[1].dependencyFlags = VK_DEPENDENCY_BY_REGION_BIT;

		// Create the actual renderpass
		VkRenderPassCreateInfo renderPassCI = vks::initializers::renderPassCreateInfo();
		renderPassCI.attachmentCount = 1;
		renderPassCI.pAttachments = &attDesc;
		renderPassCI.subpassCount = 1;
		renderPassCI.pSubpasses = &subpassDescription;
		renderPassCI.dependencyCount = 2;
		renderPassCI.pDependencies = dependencies.data();

		VkRenderPass renderpass;
		VK_CHECK_RESULT(vkCreateRenderPass(device, &renderPassCI, nullptr, &renderpass));

		VkFramebufferCreateInfo framebufferCI = vks::initializers::framebufferCreateInfo();
		framebufferCI.renderPass = renderpass;
		framebufferCI.attachmentCount = 1;
		framebufferCI.pAttachments = &textures.lutBrdf.view;
		framebufferCI.width = dim;
		framebufferCI.height = dim;
		framebufferCI.layers = 1;
		
		VkFramebuffer framebuffer;
		VK_CHECK_RESULT(vkCreateFramebuffer(device, &framebufferCI, nullptr, &framebuffer));

		// Desriptors
		VkDescriptorSetLayout descriptorsetlayout;
		std::vector<VkDescriptorSetLayoutBinding> setLayoutBindings = {};
		VkDescriptorSetLayoutCreateInfo descriptorsetlayoutCI = vks::initializers::descriptorSetLayoutCreateInfo(setLayoutBindings);
		VK_CHECK_RESULT(vkCreateDescriptorSetLayout(device, &descriptorsetlayoutCI, nullptr, &descriptorsetlayout));

		// Descriptor Pool
		std::vector<VkDescriptorPoolSize> poolSizes = { vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1) };
		VkDescriptorPoolCreateInfo descriptorPoolCI = vks::initializers::descriptorPoolCreateInfo(poolSizes, 2);
		VkDescriptorPool descriptorpool;
		VK_CHECK_RESULT(vkCreateDescriptorPool(device, &descriptorPoolCI, nullptr, &descriptorpool));

		// Descriptor sets
		VkDescriptorSet descriptorset;
		VkDescriptorSetAllocateInfo allocInfo = vks::initializers::descriptorSetAllocateInfo(descriptorpool, &descriptorsetlayout, 1);
		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &allocInfo, &descriptorset));

		// Pipeline layout
		VkPipelineLayout pipelinelayout;
		VkPipelineLayoutCreateInfo pipelineLayoutCI = vks::initializers::pipelineLayoutCreateInfo(&descriptorsetlayout, 1);
		VK_CHECK_RESULT(vkCreatePipelineLayout(device, &pipelineLayoutCI, nullptr, &pipelinelayout));

		// Pipeline
		VkPipelineInputAssemblyStateCreateInfo inputAssemblyState = vks::initializers::pipelineInputAssemblyStateCreateInfo(VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST, 0, VK_FALSE);
		VkPipelineRasterizationStateCreateInfo rasterizationState = vks::initializers::pipelineRasterizationStateCreateInfo(VK_POLYGON_MODE_FILL, VK_CULL_MODE_NONE, VK_FRONT_FACE_COUNTER_CLOCKWISE);
		VkPipelineColorBlendAttachmentState blendAttachmentState = vks::initializers::pipelineColorBlendAttachmentState(0xf, VK_FALSE);
		VkPipelineColorBlendStateCreateInfo colorBlendState = vks::initializers::pipelineColorBlendStateCreateInfo(1, &blendAttachmentState);
		VkPipelineDepthStencilStateCreateInfo depthStencilState = vks::initializers::pipelineDepthStencilStateCreateInfo(VK_FALSE, VK_FALSE, VK_COMPARE_OP_LESS_OR_EQUAL);
		VkPipelineViewportStateCreateInfo viewportState = vks::initializers::pipelineViewportStateCreateInfo(1, 1);
		VkPipelineMultisampleStateCreateInfo multisampleState = vks::initializers::pipelineMultisampleStateCreateInfo(VK_SAMPLE_COUNT_1_BIT);
		std::vector<VkDynamicState> dynamicStateEnables = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };
		VkPipelineDynamicStateCreateInfo dynamicState = vks::initializers::pipelineDynamicStateCreateInfo(dynamicStateEnables);
		VkPipelineVertexInputStateCreateInfo emptyInputState = vks::initializers::pipelineVertexInputStateCreateInfo();
		std::array<VkPipelineShaderStageCreateInfo, 2> shaderStages;

		VkGraphicsPipelineCreateInfo pipelineCI = vks::initializers::pipelineCreateInfo(pipelinelayout, renderpass);
		pipelineCI.pInputAssemblyState = &inputAssemblyState;
		pipelineCI.pRasterizationState = &rasterizationState;
		pipelineCI.pColorBlendState = &colorBlendState;
		pipelineCI.pMultisampleState = &multisampleState;
		pipelineCI.pViewportState = &viewportState;
		pipelineCI.pDepthStencilState = &depthStencilState;
		pipelineCI.pDynamicState = &dynamicState;
		pipelineCI.stageCount = 2;
		pipelineCI.pStages = shaderStages.data();
		pipelineCI.pVertexInputState = &emptyInputState;

		// Look-up-table (from BRDF) pipeline
		shaderStages[0] = loadShader(getAssetPath() +  "shaders/pbribl/genbrdflut.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
		shaderStages[1] = loadShader(getAssetPath() +  "shaders/pbribl/genbrdflut.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
		VkPipeline pipeline;
		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCI, nullptr, &pipeline));

		// Render
		VkClearValue clearValues[1];
		clearValues[0].color = { { 0.0f, 0.0f, 0.0f, 1.0f } };

		VkRenderPassBeginInfo renderPassBeginInfo = vks::initializers::renderPassBeginInfo();
		renderPassBeginInfo.renderPass = renderpass;
		renderPassBeginInfo.renderArea.extent.width = dim;
		renderPassBeginInfo.renderArea.extent.height = dim;
		renderPassBeginInfo.clearValueCount = 1;
		renderPassBeginInfo.pClearValues = clearValues;
		renderPassBeginInfo.framebuffer = framebuffer;

		VkCommandBuffer cmdBuf = vulkanDevice->createCommandBuffer(VK_COMMAND_BUFFER_LEVEL_PRIMARY, true);
		vkCmdBeginRenderPass(cmdBuf, &renderPassBeginInfo, VK_SUBPASS_CONTENTS_INLINE);
		VkViewport viewport = vks::initializers::viewport((float)dim, (float)dim, 0.0f, 1.0f);
		VkRect2D scissor = vks::initializers::rect2D(dim, dim, 0, 0);
		vkCmdSetViewport(cmdBuf, 0, 1, &viewport);
		vkCmdSetScissor(cmdBuf, 0, 1, &scissor);
		vkCmdBindPipeline(cmdBuf, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
		vkCmdDraw(cmdBuf, 3, 1, 0, 0);
		vkCmdEndRenderPass(cmdBuf);
		vulkanDevice->flushCommandBuffer(cmdBuf, queue);

		vkQueueWaitIdle(queue);
		
		// todo: cleanup
		vkDestroyPipeline(device, pipeline, nullptr);
		vkDestroyPipelineLayout(device, pipelinelayout, nullptr);
		vkDestroyRenderPass(device, renderpass, nullptr);
		vkDestroyFramebuffer(device, framebuffer, nullptr);
		vkDestroyDescriptorSetLayout(device, descriptorsetlayout, nullptr);
		vkDestroyDescriptorPool(device, descriptorpool, nullptr);

		auto tEnd = std::chrono::high_resolution_clock::now();
		auto tDiff = std::chrono::duration<double, std::milli>(tEnd - tStart).count();
		std::cout << "Generating BRDF LUT took " << tDiff << " ms" << std::endl;
	}

	// Generate an irradiance cube map from the environment cube map
	void generateIrradianceCube()
	{
		auto tStart = std::chrono::high_resolution_clock::now();

		const VkFormat format = VK_FORMAT_R32G32B32A32_SFLOAT;
		const int32_t dim = 64;
		const uint32_t numMips = static_cast<uint32_t>(floor(log2(dim))) + 1;

		// Pre-filtered cube map
		// Image
		VkImageCreateInfo imageCI = vks::initializers::imageCreateInfo();
		imageCI.imageType = VK_IMAGE_TYPE_2D;
		imageCI.format = format;
		imageCI.extent.width = dim;
		imageCI.extent.height = dim;
		imageCI.extent.depth = 1;
		imageCI.mipLevels = numMips;
		imageCI.arrayLayers = 6;
		imageCI.samples = VK_SAMPLE_COUNT_1_BIT;
		imageCI.tiling = VK_IMAGE_TILING_OPTIMAL;
		imageCI.usage = VK_IMAGE_USAGE_SAMPLED_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;
		imageCI.flags = VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT;
		VK_CHECK_RESULT(vkCreateImage(device, &imageCI, nullptr, &textures.irradianceCube.image));
		VkMemoryAllocateInfo memAlloc = vks::initializers::memoryAllocateInfo();
		VkMemoryRequirements memReqs;
		vkGetImageMemoryRequirements(device, textures.irradianceCube.image, &memReqs);
		memAlloc.allocationSize = memReqs.size;
		memAlloc.memoryTypeIndex = vulkanDevice->getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
		VK_CHECK_RESULT(vkAllocateMemory(device, &memAlloc, nullptr, &textures.irradianceCube.deviceMemory));
		VK_CHECK_RESULT(vkBindImageMemory(device, textures.irradianceCube.image, textures.irradianceCube.deviceMemory, 0));
		// Image view
		VkImageViewCreateInfo viewCI = vks::initializers::imageViewCreateInfo();
		viewCI.viewType = VK_IMAGE_VIEW_TYPE_CUBE;
		viewCI.format = format;
		viewCI.subresourceRange = {};
		viewCI.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
		viewCI.subresourceRange.levelCount = numMips;
		viewCI.subresourceRange.layerCount = 6;
		viewCI.image = textures.irradianceCube.image;
		VK_CHECK_RESULT(vkCreateImageView(device, &viewCI, nullptr, &textures.irradianceCube.view));
		// Sampler
		VkSamplerCreateInfo samplerCI = vks::initializers::samplerCreateInfo();
		samplerCI.magFilter = VK_FILTER_LINEAR;
		samplerCI.minFilter = VK_FILTER_LINEAR;
		samplerCI.mipmapMode = VK_SAMPLER_MIPMAP_MODE_LINEAR;
		samplerCI.addressModeU = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
		samplerCI.addressModeV = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
		samplerCI.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
		samplerCI.minLod = 0.0f;
		samplerCI.maxLod = static_cast<float>(numMips);
		samplerCI.borderColor = VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE;
		VK_CHECK_RESULT(vkCreateSampler(device, &samplerCI, nullptr, &textures.irradianceCube.sampler));

		textures.irradianceCube.descriptor.imageView = textures.irradianceCube.view;
		textures.irradianceCube.descriptor.sampler = textures.irradianceCube.sampler;
		textures.irradianceCube.descriptor.imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
		textures.irradianceCube.device = vulkanDevice;

		// FB, Att, RP, Pipe, etc.
		VkAttachmentDescription attDesc = {};
		// Color attachment
		attDesc.format = format;
		attDesc.samples = VK_SAMPLE_COUNT_1_BIT;
		attDesc.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
		attDesc.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
		attDesc.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
		attDesc.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
		attDesc.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
		attDesc.finalLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
		VkAttachmentReference colorReference = { 0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL };

		VkSubpassDescription subpassDescription = {};
		subpassDescription.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
		subpassDescription.colorAttachmentCount = 1;
		subpassDescription.pColorAttachments = &colorReference;

		// Use subpass dependencies for layout transitions
		std::array<VkSubpassDependency, 2> dependencies;
		dependencies[0].srcSubpass = VK_SUBPASS_EXTERNAL;
		dependencies[0].dstSubpass = 0;
		dependencies[0].srcStageMask = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
		dependencies[0].dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
		dependencies[0].srcAccessMask = VK_ACCESS_MEMORY_READ_BIT;
		dependencies[0].dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
		dependencies[0].dependencyFlags = VK_DEPENDENCY_BY_REGION_BIT;
		dependencies[1].srcSubpass = 0;
		dependencies[1].dstSubpass = VK_SUBPASS_EXTERNAL;
		dependencies[1].srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
		dependencies[1].dstStageMask = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
		dependencies[1].srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
		dependencies[1].dstAccessMask = VK_ACCESS_MEMORY_READ_BIT;
		dependencies[1].dependencyFlags = VK_DEPENDENCY_BY_REGION_BIT;

		// Renderpass
		VkRenderPassCreateInfo renderPassCI = vks::initializers::renderPassCreateInfo();
		renderPassCI.attachmentCount = 1;
		renderPassCI.pAttachments = &attDesc;
		renderPassCI.subpassCount = 1;
		renderPassCI.pSubpasses = &subpassDescription;
		renderPassCI.dependencyCount = 2;
		renderPassCI.pDependencies = dependencies.data();
		VkRenderPass renderpass;
		VK_CHECK_RESULT(vkCreateRenderPass(device, &renderPassCI, nullptr, &renderpass));

		struct {
			VkImage image;
			VkImageView view;
			VkDeviceMemory memory;
			VkFramebuffer framebuffer;
		} offscreen;

		// Offfscreen framebuffer
		{
			// Color attachment
			VkImageCreateInfo imageCreateInfo = vks::initializers::imageCreateInfo();
			imageCreateInfo.imageType = VK_IMAGE_TYPE_2D;
			imageCreateInfo.format = format;
			imageCreateInfo.extent.width = dim;
			imageCreateInfo.extent.height = dim;
			imageCreateInfo.extent.depth = 1;
			imageCreateInfo.mipLevels = 1;
			imageCreateInfo.arrayLayers = 1;
			imageCreateInfo.samples = VK_SAMPLE_COUNT_1_BIT;
			imageCreateInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
			imageCreateInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
			imageCreateInfo.usage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
			imageCreateInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
			VK_CHECK_RESULT(vkCreateImage(device, &imageCreateInfo, nullptr, &offscreen.image));

			VkMemoryAllocateInfo memAlloc = vks::initializers::memoryAllocateInfo();
			VkMemoryRequirements memReqs;
			vkGetImageMemoryRequirements(device, offscreen.image, &memReqs);
			memAlloc.allocationSize = memReqs.size;
			memAlloc.memoryTypeIndex = vulkanDevice->getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
			VK_CHECK_RESULT(vkAllocateMemory(device, &memAlloc, nullptr, &offscreen.memory));
			VK_CHECK_RESULT(vkBindImageMemory(device, offscreen.image, offscreen.memory, 0));

			VkImageViewCreateInfo colorImageView = vks::initializers::imageViewCreateInfo();
			colorImageView.viewType = VK_IMAGE_VIEW_TYPE_2D;
			colorImageView.format = format;
			colorImageView.flags = 0;
			colorImageView.subresourceRange = {};
			colorImageView.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
			colorImageView.subresourceRange.baseMipLevel = 0;
			colorImageView.subresourceRange.levelCount = 1;
			colorImageView.subresourceRange.baseArrayLayer = 0;
			colorImageView.subresourceRange.layerCount = 1;
			colorImageView.image = offscreen.image;
			VK_CHECK_RESULT(vkCreateImageView(device, &colorImageView, nullptr, &offscreen.view));

			VkFramebufferCreateInfo fbufCreateInfo = vks::initializers::framebufferCreateInfo();
			fbufCreateInfo.renderPass = renderpass;
			fbufCreateInfo.attachmentCount = 1;
			fbufCreateInfo.pAttachments = &offscreen.view;
			fbufCreateInfo.width = dim;
			fbufCreateInfo.height = dim;
			fbufCreateInfo.layers = 1;
			VK_CHECK_RESULT(vkCreateFramebuffer(device, &fbufCreateInfo, nullptr, &offscreen.framebuffer));

			VkCommandBuffer layoutCmd = VulkanExampleBase::createCommandBuffer(VK_COMMAND_BUFFER_LEVEL_PRIMARY, true);
			vks::tools::setImageLayout(
				layoutCmd,
				offscreen.image,
				VK_IMAGE_ASPECT_COLOR_BIT,
				VK_IMAGE_LAYOUT_UNDEFINED,
				VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL);
			VulkanExampleBase::flushCommandBuffer(layoutCmd, queue, true);
		}

		// Descriptors
		VkDescriptorSetLayout descriptorsetlayout;
		std::vector<VkDescriptorSetLayoutBinding> setLayoutBindings = {
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, VK_SHADER_STAGE_FRAGMENT_BIT, 0),
		};
		VkDescriptorSetLayoutCreateInfo descriptorsetlayoutCI = vks::initializers::descriptorSetLayoutCreateInfo(setLayoutBindings);
		VK_CHECK_RESULT(vkCreateDescriptorSetLayout(device, &descriptorsetlayoutCI, nullptr, &descriptorsetlayout));

		// Descriptor Pool
		std::vector<VkDescriptorPoolSize> poolSizes = { vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1) };
		VkDescriptorPoolCreateInfo descriptorPoolCI = vks::initializers::descriptorPoolCreateInfo(poolSizes, 2);
		VkDescriptorPool descriptorpool;
		VK_CHECK_RESULT(vkCreateDescriptorPool(device, &descriptorPoolCI, nullptr, &descriptorpool));

		// Descriptor sets
		VkDescriptorSet descriptorset;
		VkDescriptorSetAllocateInfo allocInfo = vks::initializers::descriptorSetAllocateInfo(descriptorpool, &descriptorsetlayout, 1);
		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &allocInfo, &descriptorset));
		VkWriteDescriptorSet writeDescriptorSet = vks::initializers::writeDescriptorSet(descriptorset, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 0, &textures.environmentCube.descriptor);
		vkUpdateDescriptorSets(device, 1, &writeDescriptorSet, 0, nullptr);

		// Pipeline layout
		struct PushBlock {
			glm::mat4 mvp;
			// Sampling deltas
			float deltaPhi = (2.0f * float(M_PI)) / 180.0f;
			float deltaTheta = (0.5f * float(M_PI)) / 64.0f;
		} pushBlock;

		VkPipelineLayout pipelinelayout;
		std::vector<VkPushConstantRange> pushConstantRanges = {
			vks::initializers::pushConstantRange(VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT, sizeof(PushBlock), 0),
		};
		VkPipelineLayoutCreateInfo pipelineLayoutCI = vks::initializers::pipelineLayoutCreateInfo(&descriptorsetlayout, 1);
		pipelineLayoutCI.pushConstantRangeCount = 1;
		pipelineLayoutCI.pPushConstantRanges = pushConstantRanges.data();
		VK_CHECK_RESULT(vkCreatePipelineLayout(device, &pipelineLayoutCI, nullptr, &pipelinelayout));

		// Pipeline
		VkPipelineInputAssemblyStateCreateInfo inputAssemblyState = vks::initializers::pipelineInputAssemblyStateCreateInfo(VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST, 0, VK_FALSE);
		VkPipelineRasterizationStateCreateInfo rasterizationState = vks::initializers::pipelineRasterizationStateCreateInfo(VK_POLYGON_MODE_FILL, VK_CULL_MODE_NONE, VK_FRONT_FACE_COUNTER_CLOCKWISE);
		VkPipelineColorBlendAttachmentState blendAttachmentState = vks::initializers::pipelineColorBlendAttachmentState(0xf, VK_FALSE);
		VkPipelineColorBlendStateCreateInfo colorBlendState = vks::initializers::pipelineColorBlendStateCreateInfo(1, &blendAttachmentState);
		VkPipelineDepthStencilStateCreateInfo depthStencilState = vks::initializers::pipelineDepthStencilStateCreateInfo(VK_FALSE, VK_FALSE, VK_COMPARE_OP_LESS_OR_EQUAL);
		VkPipelineViewportStateCreateInfo viewportState = vks::initializers::pipelineViewportStateCreateInfo(1, 1);
		VkPipelineMultisampleStateCreateInfo multisampleState = vks::initializers::pipelineMultisampleStateCreateInfo(VK_SAMPLE_COUNT_1_BIT);
		std::vector<VkDynamicState> dynamicStateEnables = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };
		VkPipelineDynamicStateCreateInfo dynamicState = vks::initializers::pipelineDynamicStateCreateInfo(dynamicStateEnables);
		// Vertex input state
		VkVertexInputBindingDescription vertexInputBinding = vks::initializers::vertexInputBindingDescription(0, vertexLayout.stride(), VK_VERTEX_INPUT_RATE_VERTEX);
		VkVertexInputAttributeDescription vertexInputAttribute = vks::initializers::vertexInputAttributeDescription(0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0);

		VkPipelineVertexInputStateCreateInfo vertexInputState = vks::initializers::pipelineVertexInputStateCreateInfo();
		vertexInputState.vertexBindingDescriptionCount = 1;
		vertexInputState.pVertexBindingDescriptions = &vertexInputBinding;
		vertexInputState.vertexAttributeDescriptionCount = 1;
		vertexInputState.pVertexAttributeDescriptions = &vertexInputAttribute;

		std::array<VkPipelineShaderStageCreateInfo, 2> shaderStages;

		VkGraphicsPipelineCreateInfo pipelineCI = vks::initializers::pipelineCreateInfo(pipelinelayout, renderpass);
		pipelineCI.pInputAssemblyState = &inputAssemblyState;
		pipelineCI.pRasterizationState = &rasterizationState;
		pipelineCI.pColorBlendState = &colorBlendState;
		pipelineCI.pMultisampleState = &multisampleState;
		pipelineCI.pViewportState = &viewportState;
		pipelineCI.pDepthStencilState = &depthStencilState;
		pipelineCI.pDynamicState = &dynamicState;
		pipelineCI.stageCount = 2;
		pipelineCI.pStages = shaderStages.data();
		pipelineCI.pVertexInputState = &vertexInputState;
		pipelineCI.renderPass = renderpass;

		shaderStages[0] = loadShader(getAssetPath() +  "shaders/pbribl/filtercube.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
		shaderStages[1] = loadShader(getAssetPath() +  "shaders/pbribl/irradiancecube.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
		VkPipeline pipeline;
		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCI, nullptr, &pipeline));

		// Render

		VkClearValue clearValues[1];
		clearValues[0].color = { { 0.0f, 0.0f, 0.2f, 0.0f } };

		VkRenderPassBeginInfo renderPassBeginInfo = vks::initializers::renderPassBeginInfo();
		// Reuse render pass from example pass
		renderPassBeginInfo.renderPass = renderpass;
		renderPassBeginInfo.framebuffer = offscreen.framebuffer;
		renderPassBeginInfo.renderArea.extent.width = dim;
		renderPassBeginInfo.renderArea.extent.height = dim;
		renderPassBeginInfo.clearValueCount = 1;
		renderPassBeginInfo.pClearValues = clearValues;

		std::vector<glm::mat4> matrices = {
			// POSITIVE_X
			glm::rotate(glm::rotate(glm::mat4(1.0f), glm::radians(90.0f), glm::vec3(0.0f, 1.0f, 0.0f)), glm::radians(180.0f), glm::vec3(1.0f, 0.0f, 0.0f)),
			// NEGATIVE_X
			glm::rotate(glm::rotate(glm::mat4(1.0f), glm::radians(-90.0f), glm::vec3(0.0f, 1.0f, 0.0f)), glm::radians(180.0f), glm::vec3(1.0f, 0.0f, 0.0f)),
			// POSITIVE_Y
			glm::rotate(glm::mat4(1.0f), glm::radians(-90.0f), glm::vec3(1.0f, 0.0f, 0.0f)),
			// NEGATIVE_Y
			glm::rotate(glm::mat4(1.0f), glm::radians(90.0f), glm::vec3(1.0f, 0.0f, 0.0f)),
			// POSITIVE_Z
			glm::rotate(glm::mat4(1.0f), glm::radians(180.0f), glm::vec3(1.0f, 0.0f, 0.0f)),
			// NEGATIVE_Z
			glm::rotate(glm::mat4(1.0f), glm::radians(180.0f), glm::vec3(0.0f, 0.0f, 1.0f)),
		};

		VkCommandBuffer cmdBuf = vulkanDevice->createCommandBuffer(VK_COMMAND_BUFFER_LEVEL_PRIMARY, true);

		VkViewport viewport = vks::initializers::viewport((float)dim, (float)dim, 0.0f, 1.0f);
		VkRect2D scissor = vks::initializers::rect2D(dim, dim, 0, 0);

		vkCmdSetViewport(cmdBuf, 0, 1, &viewport);
		vkCmdSetScissor(cmdBuf, 0, 1, &scissor);

		VkImageSubresourceRange subresourceRange = {};
		subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
		subresourceRange.baseMipLevel = 0;
		subresourceRange.levelCount = numMips;
		subresourceRange.layerCount = 6;

		// Change image layout for all cubemap faces to transfer destination
		vks::tools::setImageLayout(
			cmdBuf,
			textures.irradianceCube.image,
			VK_IMAGE_LAYOUT_UNDEFINED,
			VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
			subresourceRange);

		for (uint32_t m = 0; m < numMips; m++) {
			for (uint32_t f = 0; f < 6; f++) {
				viewport.width = static_cast<float>(dim * std::pow(0.5f, m));
				viewport.height = static_cast<float>(dim * std::pow(0.5f, m));
				vkCmdSetViewport(cmdBuf, 0, 1, &viewport);

				// Render scene from cube face's point of view
				vkCmdBeginRenderPass(cmdBuf, &renderPassBeginInfo, VK_SUBPASS_CONTENTS_INLINE);

				// Update shader push constant block
				pushBlock.mvp = glm::perspective((float)(M_PI / 2.0), 1.0f, 0.1f, 512.0f) * matrices[f];

				vkCmdPushConstants(cmdBuf, pipelinelayout, VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT, 0, sizeof(PushBlock), &pushBlock);

				vkCmdBindPipeline(cmdBuf, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
				vkCmdBindDescriptorSets(cmdBuf, VK_PIPELINE_BIND_POINT_GRAPHICS, pipelinelayout, 0, 1, &descriptorset, 0, NULL);

				VkDeviceSize offsets[1] = { 0 };

				vkCmdBindVertexBuffers(cmdBuf, 0, 1, &models.skybox.vertices.buffer, offsets);
				vkCmdBindIndexBuffer(cmdBuf, models.skybox.indices.buffer, 0, VK_INDEX_TYPE_UINT32);
				vkCmdDrawIndexed(cmdBuf, models.skybox.indexCount, 1, 0, 0, 0);

				vkCmdEndRenderPass(cmdBuf);

				vks::tools::setImageLayout(
					cmdBuf,
					offscreen.image,
					VK_IMAGE_ASPECT_COLOR_BIT,
					VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
					VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL);

				// Copy region for transfer from framebuffer to cube face
				VkImageCopy copyRegion = {};

				copyRegion.srcSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
				copyRegion.srcSubresource.baseArrayLayer = 0;
				copyRegion.srcSubresource.mipLevel = 0;
				copyRegion.srcSubresource.layerCount = 1;
				copyRegion.srcOffset = { 0, 0, 0 };

				copyRegion.dstSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
				copyRegion.dstSubresource.baseArrayLayer = f;
				copyRegion.dstSubresource.mipLevel = m;
				copyRegion.dstSubresource.layerCount = 1;
				copyRegion.dstOffset = { 0, 0, 0 };

				copyRegion.extent.width = static_cast<uint32_t>(viewport.width);
				copyRegion.extent.height = static_cast<uint32_t>(viewport.height);
				copyRegion.extent.depth = 1;

				vkCmdCopyImage(
					cmdBuf,
					offscreen.image,
					VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
					textures.irradianceCube.image,
					VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
					1,
					&copyRegion);

				// Transform framebuffer color attachment back 
				vks::tools::setImageLayout(
					cmdBuf,
					offscreen.image,
					VK_IMAGE_ASPECT_COLOR_BIT,
					VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
					VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL);
			}
		}

		vks::tools::setImageLayout(
			cmdBuf,
			textures.irradianceCube.image,
			VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
			VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL,
			subresourceRange);

		vulkanDevice->flushCommandBuffer(cmdBuf, queue);

		// todo: cleanup
		vkDestroyRenderPass(device, renderpass, nullptr);
		vkDestroyFramebuffer(device, offscreen.framebuffer, nullptr);
		vkFreeMemory(device, offscreen.memory, nullptr);
		vkDestroyImageView(device, offscreen.view, nullptr);
		vkDestroyImage(device, offscreen.image, nullptr);
		vkDestroyDescriptorPool(device, descriptorpool, nullptr);
		vkDestroyDescriptorSetLayout(device, descriptorsetlayout, nullptr);
		vkDestroyPipeline(device, pipeline, nullptr);
		vkDestroyPipelineLayout(device, pipelinelayout, nullptr);

		auto tEnd = std::chrono::high_resolution_clock::now();
		auto tDiff = std::chrono::duration<double, std::milli>(tEnd - tStart).count();
		std::cout << "Generating irradiance cube with " << numMips << " mip levels took " << tDiff << " ms" << std::endl;
	}

	// Prefilter environment cubemap
	// See https://placeholderart.wordpress.com/2015/07/28/implementation-notes-runtime-environment-map-filtering-for-image-based-lighting/
	void generatePrefilteredCube()
	{
		auto tStart = std::chrono::high_resolution_clock::now();

		const VkFormat format = VK_FORMAT_R16G16B16A16_SFLOAT;
		const int32_t dim = 512;
		const uint32_t numMips = static_cast<uint32_t>(floor(log2(dim))) + 1;

		// Pre-filtered cube map
		// Image
		VkImageCreateInfo imageCI = vks::initializers::imageCreateInfo();
		imageCI.imageType = VK_IMAGE_TYPE_2D;
		imageCI.format = format;
		imageCI.extent.width = dim;
		imageCI.extent.height = dim;
		imageCI.extent.depth = 1;
		imageCI.mipLevels = numMips;
		imageCI.arrayLayers = 6;
		imageCI.samples = VK_SAMPLE_COUNT_1_BIT;
		imageCI.tiling = VK_IMAGE_TILING_OPTIMAL;
		imageCI.usage = VK_IMAGE_USAGE_SAMPLED_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;
		imageCI.flags = VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT;
		VK_CHECK_RESULT(vkCreateImage(device, &imageCI, nullptr, &textures.prefilteredCube.image));
		VkMemoryAllocateInfo memAlloc = vks::initializers::memoryAllocateInfo();
		VkMemoryRequirements memReqs;
		vkGetImageMemoryRequirements(device, textures.prefilteredCube.image, &memReqs);
		memAlloc.allocationSize = memReqs.size;
		memAlloc.memoryTypeIndex = vulkanDevice->getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
		VK_CHECK_RESULT(vkAllocateMemory(device, &memAlloc, nullptr, &textures.prefilteredCube.deviceMemory));
		VK_CHECK_RESULT(vkBindImageMemory(device, textures.prefilteredCube.image, textures.prefilteredCube.deviceMemory, 0));
		// Image view
		VkImageViewCreateInfo viewCI = vks::initializers::imageViewCreateInfo();
		viewCI.viewType = VK_IMAGE_VIEW_TYPE_CUBE;
		viewCI.format = format;
		viewCI.subresourceRange = {};
		viewCI.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
		viewCI.subresourceRange.levelCount = numMips;
		viewCI.subresourceRange.layerCount = 6;
		viewCI.image = textures.prefilteredCube.image;
		VK_CHECK_RESULT(vkCreateImageView(device, &viewCI, nullptr, &textures.prefilteredCube.view));
		// Sampler
		VkSamplerCreateInfo samplerCI = vks::initializers::samplerCreateInfo();
		samplerCI.magFilter = VK_FILTER_LINEAR;
		samplerCI.minFilter = VK_FILTER_LINEAR;
		samplerCI.mipmapMode = VK_SAMPLER_MIPMAP_MODE_LINEAR;
		samplerCI.addressModeU = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
		samplerCI.addressModeV = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
		samplerCI.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
		samplerCI.minLod = 0.0f;
		samplerCI.maxLod = static_cast<float>(numMips);
		samplerCI.borderColor = VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE;
		VK_CHECK_RESULT(vkCreateSampler(device, &samplerCI, nullptr, &textures.prefilteredCube.sampler));

		textures.prefilteredCube.descriptor.imageView = textures.prefilteredCube.view;
		textures.prefilteredCube.descriptor.sampler = textures.prefilteredCube.sampler;
		textures.prefilteredCube.descriptor.imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
		textures.prefilteredCube.device = vulkanDevice;

		// FB, Att, RP, Pipe, etc.
		VkAttachmentDescription attDesc = {};
		// Color attachment
		attDesc.format = format;
		attDesc.samples = VK_SAMPLE_COUNT_1_BIT;
		attDesc.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
		attDesc.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
		attDesc.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
		attDesc.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
		attDesc.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
		attDesc.finalLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
		VkAttachmentReference colorReference = { 0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL };

		VkSubpassDescription subpassDescription = {};
		subpassDescription.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
		subpassDescription.colorAttachmentCount = 1;
		subpassDescription.pColorAttachments = &colorReference;

		// Use subpass dependencies for layout transitions
		std::array<VkSubpassDependency, 2> dependencies;
		dependencies[0].srcSubpass = VK_SUBPASS_EXTERNAL;
		dependencies[0].dstSubpass = 0;
		dependencies[0].srcStageMask = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
		dependencies[0].dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
		dependencies[0].srcAccessMask = VK_ACCESS_MEMORY_READ_BIT;
		dependencies[0].dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
		dependencies[0].dependencyFlags = VK_DEPENDENCY_BY_REGION_BIT;
		dependencies[1].srcSubpass = 0;
		dependencies[1].dstSubpass = VK_SUBPASS_EXTERNAL;
		dependencies[1].srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
		dependencies[1].dstStageMask = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
		dependencies[1].srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
		dependencies[1].dstAccessMask = VK_ACCESS_MEMORY_READ_BIT;
		dependencies[1].dependencyFlags = VK_DEPENDENCY_BY_REGION_BIT;

		// Renderpass
		VkRenderPassCreateInfo renderPassCI = vks::initializers::renderPassCreateInfo();
		renderPassCI.attachmentCount = 1;
		renderPassCI.pAttachments = &attDesc;
		renderPassCI.subpassCount = 1;
		renderPassCI.pSubpasses = &subpassDescription;
		renderPassCI.dependencyCount = 2;
		renderPassCI.pDependencies = dependencies.data();
		VkRenderPass renderpass;
		VK_CHECK_RESULT(vkCreateRenderPass(device, &renderPassCI, nullptr, &renderpass));

		struct {
			VkImage image;
			VkImageView view;
			VkDeviceMemory memory;
			VkFramebuffer framebuffer;
		} offscreen;

		// Offfscreen framebuffer
		{
			// Color attachment
			VkImageCreateInfo imageCreateInfo = vks::initializers::imageCreateInfo();
			imageCreateInfo.imageType = VK_IMAGE_TYPE_2D;
			imageCreateInfo.format = format;
			imageCreateInfo.extent.width = dim;
			imageCreateInfo.extent.height = dim;
			imageCreateInfo.extent.depth = 1;
			imageCreateInfo.mipLevels = 1;
			imageCreateInfo.arrayLayers = 1;
			imageCreateInfo.samples = VK_SAMPLE_COUNT_1_BIT;
			imageCreateInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
			imageCreateInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
			imageCreateInfo.usage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
			imageCreateInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
			VK_CHECK_RESULT(vkCreateImage(device, &imageCreateInfo, nullptr, &offscreen.image));

			VkMemoryAllocateInfo memAlloc = vks::initializers::memoryAllocateInfo();
			VkMemoryRequirements memReqs;
			vkGetImageMemoryRequirements(device, offscreen.image, &memReqs);
			memAlloc.allocationSize = memReqs.size;
			memAlloc.memoryTypeIndex = vulkanDevice->getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
			VK_CHECK_RESULT(vkAllocateMemory(device, &memAlloc, nullptr, &offscreen.memory));
			VK_CHECK_RESULT(vkBindImageMemory(device, offscreen.image, offscreen.memory, 0));

			VkImageViewCreateInfo colorImageView = vks::initializers::imageViewCreateInfo();
			colorImageView.viewType = VK_IMAGE_VIEW_TYPE_2D;
			colorImageView.format = format;
			colorImageView.flags = 0;
			colorImageView.subresourceRange = {};
			colorImageView.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
			colorImageView.subresourceRange.baseMipLevel = 0;
			colorImageView.subresourceRange.levelCount = 1;
			colorImageView.subresourceRange.baseArrayLayer = 0;
			colorImageView.subresourceRange.layerCount = 1;
			colorImageView.image = offscreen.image;
			VK_CHECK_RESULT(vkCreateImageView(device, &colorImageView, nullptr, &offscreen.view));

			VkFramebufferCreateInfo fbufCreateInfo = vks::initializers::framebufferCreateInfo();
			fbufCreateInfo.renderPass = renderpass;
			fbufCreateInfo.attachmentCount = 1;
			fbufCreateInfo.pAttachments = &offscreen.view;
			fbufCreateInfo.width = dim;
			fbufCreateInfo.height = dim;
			fbufCreateInfo.layers = 1;
			VK_CHECK_RESULT(vkCreateFramebuffer(device, &fbufCreateInfo, nullptr, &offscreen.framebuffer));

			VkCommandBuffer layoutCmd = VulkanExampleBase::createCommandBuffer(VK_COMMAND_BUFFER_LEVEL_PRIMARY, true);
			vks::tools::setImageLayout(
				layoutCmd,
				offscreen.image,
				VK_IMAGE_ASPECT_COLOR_BIT,
				VK_IMAGE_LAYOUT_UNDEFINED,
				VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL);
			VulkanExampleBase::flushCommandBuffer(layoutCmd, queue, true);
		}

		// Descriptors
		VkDescriptorSetLayout descriptorsetlayout;
		std::vector<VkDescriptorSetLayoutBinding> setLayoutBindings = {
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, VK_SHADER_STAGE_FRAGMENT_BIT, 0),
		};
		VkDescriptorSetLayoutCreateInfo descriptorsetlayoutCI = vks::initializers::descriptorSetLayoutCreateInfo(setLayoutBindings);
		VK_CHECK_RESULT(vkCreateDescriptorSetLayout(device, &descriptorsetlayoutCI, nullptr, &descriptorsetlayout));

		// Descriptor Pool
		std::vector<VkDescriptorPoolSize> poolSizes = { vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1) };
		VkDescriptorPoolCreateInfo descriptorPoolCI = vks::initializers::descriptorPoolCreateInfo(poolSizes, 2);
		VkDescriptorPool descriptorpool;
		VK_CHECK_RESULT(vkCreateDescriptorPool(device, &descriptorPoolCI, nullptr, &descriptorpool));

		// Descriptor sets
		VkDescriptorSet descriptorset;
		VkDescriptorSetAllocateInfo allocInfo =	vks::initializers::descriptorSetAllocateInfo(descriptorpool, &descriptorsetlayout, 1);
		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &allocInfo, &descriptorset));
		VkWriteDescriptorSet writeDescriptorSet = vks::initializers::writeDescriptorSet(descriptorset, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 0, &textures.environmentCube.descriptor);
		vkUpdateDescriptorSets(device, 1, &writeDescriptorSet, 0, nullptr);

		// Pipeline layout
		struct PushBlock {
			glm::mat4 mvp;
			float roughness;
			uint32_t numSamples = 32u;
		} pushBlock;

		VkPipelineLayout pipelinelayout;
		std::vector<VkPushConstantRange> pushConstantRanges = {
			vks::initializers::pushConstantRange(VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT, sizeof(PushBlock), 0),
		};
		VkPipelineLayoutCreateInfo pipelineLayoutCI = vks::initializers::pipelineLayoutCreateInfo(&descriptorsetlayout, 1);
		pipelineLayoutCI.pushConstantRangeCount = 1;
		pipelineLayoutCI.pPushConstantRanges = pushConstantRanges.data();
		VK_CHECK_RESULT(vkCreatePipelineLayout(device, &pipelineLayoutCI, nullptr, &pipelinelayout));

		// Pipeline
		VkPipelineInputAssemblyStateCreateInfo inputAssemblyState = vks::initializers::pipelineInputAssemblyStateCreateInfo(VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST, 0, VK_FALSE);
		VkPipelineRasterizationStateCreateInfo rasterizationState = vks::initializers::pipelineRasterizationStateCreateInfo(VK_POLYGON_MODE_FILL, VK_CULL_MODE_NONE, VK_FRONT_FACE_COUNTER_CLOCKWISE);
		VkPipelineColorBlendAttachmentState blendAttachmentState = vks::initializers::pipelineColorBlendAttachmentState(0xf, VK_FALSE);
		VkPipelineColorBlendStateCreateInfo colorBlendState = vks::initializers::pipelineColorBlendStateCreateInfo(1, &blendAttachmentState);
		VkPipelineDepthStencilStateCreateInfo depthStencilState = vks::initializers::pipelineDepthStencilStateCreateInfo(VK_FALSE, VK_FALSE, VK_COMPARE_OP_LESS_OR_EQUAL);
		VkPipelineViewportStateCreateInfo viewportState = vks::initializers::pipelineViewportStateCreateInfo(1, 1);
		VkPipelineMultisampleStateCreateInfo multisampleState = vks::initializers::pipelineMultisampleStateCreateInfo(VK_SAMPLE_COUNT_1_BIT);
		std::vector<VkDynamicState> dynamicStateEnables = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };
		VkPipelineDynamicStateCreateInfo dynamicState = vks::initializers::pipelineDynamicStateCreateInfo(dynamicStateEnables);
		// Vertex input state
		VkVertexInputBindingDescription vertexInputBinding = vks::initializers::vertexInputBindingDescription(0, vertexLayout.stride(), VK_VERTEX_INPUT_RATE_VERTEX);
		VkVertexInputAttributeDescription vertexInputAttribute = vks::initializers::vertexInputAttributeDescription(0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0);

		VkPipelineVertexInputStateCreateInfo vertexInputState = vks::initializers::pipelineVertexInputStateCreateInfo();
		vertexInputState.vertexBindingDescriptionCount = 1;
		vertexInputState.pVertexBindingDescriptions = &vertexInputBinding;
		vertexInputState.vertexAttributeDescriptionCount = 1;
		vertexInputState.pVertexAttributeDescriptions = &vertexInputAttribute;

		std::array<VkPipelineShaderStageCreateInfo, 2> shaderStages;

		VkGraphicsPipelineCreateInfo pipelineCI = vks::initializers::pipelineCreateInfo(pipelinelayout, renderpass);
		pipelineCI.pInputAssemblyState = &inputAssemblyState;
		pipelineCI.pRasterizationState = &rasterizationState;
		pipelineCI.pColorBlendState = &colorBlendState;
		pipelineCI.pMultisampleState = &multisampleState;
		pipelineCI.pViewportState = &viewportState;
		pipelineCI.pDepthStencilState = &depthStencilState;
		pipelineCI.pDynamicState = &dynamicState;
		pipelineCI.stageCount = 2;
		pipelineCI.pStages = shaderStages.data();
		pipelineCI.pVertexInputState = &vertexInputState;
		pipelineCI.renderPass = renderpass;

		shaderStages[0] = loadShader(getAssetPath() +  "shaders/pbribl/filtercube.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
		shaderStages[1] = loadShader(getAssetPath() +  "shaders/pbribl/prefilterenvmap.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
		VkPipeline pipeline;
		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCI, nullptr, &pipeline));

		// Render

		VkClearValue clearValues[1];
		clearValues[0].color = { { 0.0f, 0.0f, 0.2f, 0.0f } };

		VkRenderPassBeginInfo renderPassBeginInfo = vks::initializers::renderPassBeginInfo();
		// Reuse render pass from example pass
		renderPassBeginInfo.renderPass = renderpass;
		renderPassBeginInfo.framebuffer = offscreen.framebuffer;
		renderPassBeginInfo.renderArea.extent.width = dim;
		renderPassBeginInfo.renderArea.extent.height = dim;
		renderPassBeginInfo.clearValueCount = 1;
		renderPassBeginInfo.pClearValues = clearValues;

		std::vector<glm::mat4> matrices = {
			// POSITIVE_X
			glm::rotate(glm::rotate(glm::mat4(1.0f), glm::radians(90.0f), glm::vec3(0.0f, 1.0f, 0.0f)), glm::radians(180.0f), glm::vec3(1.0f, 0.0f, 0.0f)),
			// NEGATIVE_X
			glm::rotate(glm::rotate(glm::mat4(1.0f), glm::radians(-90.0f), glm::vec3(0.0f, 1.0f, 0.0f)), glm::radians(180.0f), glm::vec3(1.0f, 0.0f, 0.0f)),
			// POSITIVE_Y
			glm::rotate(glm::mat4(1.0f), glm::radians(-90.0f), glm::vec3(1.0f, 0.0f, 0.0f)),
			// NEGATIVE_Y
			glm::rotate(glm::mat4(1.0f), glm::radians(90.0f), glm::vec3(1.0f, 0.0f, 0.0f)),
			// POSITIVE_Z
			glm::rotate(glm::mat4(1.0f), glm::radians(180.0f), glm::vec3(1.0f, 0.0f, 0.0f)),
			// NEGATIVE_Z
			glm::rotate(glm::mat4(1.0f), glm::radians(180.0f), glm::vec3(0.0f, 0.0f, 1.0f)),
		};

		VkCommandBuffer cmdBuf = vulkanDevice->createCommandBuffer(VK_COMMAND_BUFFER_LEVEL_PRIMARY, true);

		VkViewport viewport = vks::initializers::viewport((float)dim, (float)dim, 0.0f, 1.0f);
		VkRect2D scissor = vks::initializers::rect2D(dim, dim, 0, 0);
		
		vkCmdSetViewport(cmdBuf, 0, 1, &viewport);
		vkCmdSetScissor(cmdBuf, 0, 1, &scissor);

		VkImageSubresourceRange subresourceRange = {};
		subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
		subresourceRange.baseMipLevel = 0;
		subresourceRange.levelCount = numMips;
		subresourceRange.layerCount = 6;

		// Change image layout for all cubemap faces to transfer destination
		vks::tools::setImageLayout(
			cmdBuf,
			textures.prefilteredCube.image,
			VK_IMAGE_LAYOUT_UNDEFINED,
			VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
			subresourceRange);

		for (uint32_t m = 0; m < numMips; m++) {
			pushBlock.roughness = (float)m / (float)(numMips - 1);
			for (uint32_t f = 0; f < 6; f++) {
				viewport.width = static_cast<float>(dim * std::pow(0.5f, m));
				viewport.height = static_cast<float>(dim * std::pow(0.5f, m));
				vkCmdSetViewport(cmdBuf, 0, 1, &viewport);

				// Render scene from cube face's point of view
				vkCmdBeginRenderPass(cmdBuf, &renderPassBeginInfo, VK_SUBPASS_CONTENTS_INLINE);

				// Update shader push constant block
				pushBlock.mvp = glm::perspective((float)(M_PI / 2.0), 1.0f, 0.1f, 512.0f) * matrices[f];

				vkCmdPushConstants(cmdBuf, pipelinelayout, VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT, 0, sizeof(PushBlock), &pushBlock);

				vkCmdBindPipeline(cmdBuf, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
				vkCmdBindDescriptorSets(cmdBuf, VK_PIPELINE_BIND_POINT_GRAPHICS, pipelinelayout, 0, 1, &descriptorset, 0, NULL);

				VkDeviceSize offsets[1] = { 0 };

				vkCmdBindVertexBuffers(cmdBuf, 0, 1, &models.skybox.vertices.buffer, offsets);
				vkCmdBindIndexBuffer(cmdBuf, models.skybox.indices.buffer, 0, VK_INDEX_TYPE_UINT32);
				vkCmdDrawIndexed(cmdBuf, models.skybox.indexCount, 1, 0, 0, 0);

				vkCmdEndRenderPass(cmdBuf);

				vks::tools::setImageLayout(
					cmdBuf, 
					offscreen.image, 
					VK_IMAGE_ASPECT_COLOR_BIT, 
					VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL, 
					VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL);

				// Copy region for transfer from framebuffer to cube face
				VkImageCopy copyRegion = {};

				copyRegion.srcSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
				copyRegion.srcSubresource.baseArrayLayer = 0;
				copyRegion.srcSubresource.mipLevel = 0;
				copyRegion.srcSubresource.layerCount = 1;
				copyRegion.srcOffset = { 0, 0, 0 };

				copyRegion.dstSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
				copyRegion.dstSubresource.baseArrayLayer = f;
				copyRegion.dstSubresource.mipLevel = m;
				copyRegion.dstSubresource.layerCount = 1;
				copyRegion.dstOffset = { 0, 0, 0 };

				copyRegion.extent.width = static_cast<uint32_t>(viewport.width);
				copyRegion.extent.height = static_cast<uint32_t>(viewport.height);
				copyRegion.extent.depth = 1;

				vkCmdCopyImage(
					cmdBuf,
					offscreen.image,
					VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
					textures.prefilteredCube.image,
					VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
					1,
					&copyRegion);

				// Transform framebuffer color attachment back 
				vks::tools::setImageLayout(
					cmdBuf,
					offscreen.image,
					VK_IMAGE_ASPECT_COLOR_BIT,
					VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
					VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL);
			}
		}

		vks::tools::setImageLayout(
			cmdBuf,
			textures.prefilteredCube.image,
			VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
			VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL,
			subresourceRange);

		vulkanDevice->flushCommandBuffer(cmdBuf, queue);

		// todo: cleanup
		vkDestroyRenderPass(device, renderpass, nullptr);
		vkDestroyFramebuffer(device, offscreen.framebuffer, nullptr);
		vkFreeMemory(device, offscreen.memory, nullptr);
		vkDestroyImageView(device, offscreen.view, nullptr);
		vkDestroyImage(device, offscreen.image, nullptr);
		vkDestroyDescriptorPool(device, descriptorpool, nullptr);
		vkDestroyDescriptorSetLayout(device, descriptorsetlayout, nullptr);
		vkDestroyPipeline(device, pipeline, nullptr);
		vkDestroyPipelineLayout(device, pipelinelayout, nullptr);

		auto tEnd = std::chrono::high_resolution_clock::now();
		auto tDiff = std::chrono::duration<double, std::milli>(tEnd - tStart).count();
		std::cout << "Generating pre-filtered enivornment cube with " << numMips << " mip levels took " << tDiff << " ms" << std::endl;
	}

	// Prepare and initialize uniform buffer containing shader uniforms
	void prepareUniformBuffers()
	{
		// Objact vertex shader uniform buffer
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&uniformBuffers.object,
			sizeof(uboMatrices)));

		// Skybox vertex shader uniform buffer
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&uniformBuffers.skybox,
			sizeof(uboMatrices)));

		// Shared parameter uniform buffer
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&uniformBuffers.params,
			sizeof(uboParams)));

		// Map persistent
		VK_CHECK_RESULT(uniformBuffers.object.map());
		VK_CHECK_RESULT(uniformBuffers.skybox.map());
		VK_CHECK_RESULT(uniformBuffers.params.map());

		updateUniformBuffers();
		updateParams();
	}

	void updateUniformBuffers()
	{
		// 3D object
		uboMatrices.projection = camera.matrices.perspective;
		uboMatrices.view = camera.matrices.view;
		uboMatrices.model = glm::rotate(glm::mat4(1.0f), glm::radians(90.0f + (models.objectIndex == 1 ? 45.0f : 0.0f)), glm::vec3(0.0f, 1.0f, 0.0f));
		uboMatrices.camPos = camera.position * -1.0f;
		memcpy(uniformBuffers.object.mapped, &uboMatrices, sizeof(uboMatrices));

		// Skybox
		uboMatrices.model = glm::mat4(glm::mat3(camera.matrices.view));
		memcpy(uniformBuffers.skybox.mapped, &uboMatrices, sizeof(uboMatrices));
	}

	void updateParams()
	{
		const float p = 15.0f;
		uboParams.lights[0] = glm::vec4(-p, -p*0.5f, -p, 1.0f);
		uboParams.lights[1] = glm::vec4(-p, -p*0.5f,  p, 1.0f);
		uboParams.lights[2] = glm::vec4( p, -p*0.5f,  p, 1.0f);
		uboParams.lights[3] = glm::vec4( p, -p*0.5f, -p, 1.0f);

		memcpy(uniformBuffers.params.mapped, &uboParams, sizeof(uboParams));
	}

	void draw()
	{
		VulkanExampleBase::prepareFrame();

		submitInfo.commandBufferCount = 1;
		submitInfo.pCommandBuffers = &drawCmdBuffers[currentBuffer];
		VK_CHECK_RESULT(vkQueueSubmit(queue, 1, &submitInfo, VK_NULL_HANDLE));

		VulkanExampleBase::submitFrame();
	}

	void prepare()
	{
		VulkanExampleBase::prepare();
		loadAssets();
		generateBRDFLUT();
		generateIrradianceCube();
		generatePrefilteredCube();
		prepareUniformBuffers();
		setupDescriptors();
		preparePipelines();
		buildCommandBuffers();
		prepared = true;
	}

	virtual void render()
	{
		if (!prepared)
			return;
		draw();
	}

	virtual void viewChanged()
	{
		updateUniformBuffers();
	}

	virtual void OnUpdateUIOverlay(vks::UIOverlay *overlay)
	{
		if (overlay->header("Settings")) {
			if (overlay->comboBox("Material", &materialIndex, materialNames)) {
				buildCommandBuffers();
			}
			if (overlay->comboBox("Object type", &models.objectIndex, objectNames)) {
				updateUniformBuffers();
				buildCommandBuffers();
			}
			if (overlay->inputFloat("Exposure", &uboParams.exposure, 0.1f, 2)) {
				updateParams();
			}
			if (overlay->inputFloat("Gamma", &uboParams.gamma, 0.1f, 2)) {
				updateParams();
			}
			if (overlay->checkBox("Skybox", &displaySkybox)) {
				buildCommandBuffers();
			}
		}
	}

};

VULKAN_EXAMPLE_MAIN()