/*
* Vulkan Example - Text overlay rendering on-top of an existing scene using a separate render pass
*
* Copyright (C) 2016 by Sascha Willems - www.saschawillems.de
*
* This code is licensed under the MIT license (MIT) (http://opensource.org/licenses/MIT)
*/

#include <sstream>
#include <iomanip>
#include "vulkanexamplebase.h"
#include "VulkanglTFModel.h"
#include "../external/stb/stb_font_consolas_24_latin1.inl"

#define ENABLE_VALIDATION false

// Max. number of chars the text overlay buffer can hold
#define TEXTOVERLAY_MAX_CHAR_COUNT 2048

/*
	Mostly self-contained text overlay class
*/
class TextOverlay
{
private:
	vks::VulkanDevice *vulkanDevice;

	VkQueue queue;
	VkFormat colorFormat;
	VkFormat depthFormat;

	uint32_t *frameBufferWidth;
	uint32_t *frameBufferHeight;

	VkSampler sampler;
	VkImage image;
	VkImageView view;
	VkBuffer buffer;
	VkDeviceMemory memory;
	VkDeviceMemory imageMemory;
	VkDescriptorPool descriptorPool;
	VkDescriptorSetLayout descriptorSetLayout;
	VkDescriptorSet descriptorSet;
	VkPipelineLayout pipelineLayout;
	VkPipelineCache pipelineCache;
	VkPipeline pipeline;
	VkRenderPass renderPass;
	VkCommandPool commandPool;
	std::vector<VkFramebuffer*> frameBuffers;
	std::vector<VkPipelineShaderStageCreateInfo> shaderStages;

	// Pointer to mapped vertex buffer
	glm::vec4 *mapped = nullptr;

	stb_fontchar stbFontData[STB_FONT_consolas_24_latin1_NUM_CHARS];
	uint32_t numLetters;
public:

	enum TextAlign { alignLeft, alignCenter, alignRight };

	bool visible = true;

	std::vector<VkCommandBuffer> cmdBuffers;

	TextOverlay(
		vks::VulkanDevice *vulkanDevice,
		VkQueue queue,
		std::vector<VkFramebuffer> &framebuffers,
		VkFormat colorformat,
		VkFormat depthformat,
		uint32_t *framebufferwidth,
		uint32_t *framebufferheight,
		std::vector<VkPipelineShaderStageCreateInfo> shaderstages)
	{
		this->vulkanDevice = vulkanDevice;
		this->queue = queue;
		this->colorFormat = colorformat;
		this->depthFormat = depthformat;

		this->frameBuffers.resize(framebuffers.size());
		for (uint32_t i = 0; i < framebuffers.size(); i++)
		{
			this->frameBuffers[i] = &framebuffers[i];
		}

		this->shaderStages = shaderstages;

		this->frameBufferWidth = framebufferwidth;
		this->frameBufferHeight = framebufferheight;

		cmdBuffers.resize(framebuffers.size());
		prepareResources();
		prepareRenderPass();
		preparePipeline();
	}

	~TextOverlay()
	{
		// Free up all Vulkan resources requested by the text overlay
		vkDestroySampler(vulkanDevice->logicalDevice, sampler, nullptr);
		vkDestroyImage(vulkanDevice->logicalDevice, image, nullptr);
		vkDestroyImageView(vulkanDevice->logicalDevice, view, nullptr);
		vkDestroyBuffer(vulkanDevice->logicalDevice, buffer, nullptr);
		vkFreeMemory(vulkanDevice->logicalDevice, memory, nullptr);
		vkFreeMemory(vulkanDevice->logicalDevice, imageMemory, nullptr);
		vkDestroyDescriptorSetLayout(vulkanDevice->logicalDevice, descriptorSetLayout, nullptr);
		vkDestroyDescriptorPool(vulkanDevice->logicalDevice, descriptorPool, nullptr);
		vkDestroyPipelineLayout(vulkanDevice->logicalDevice, pipelineLayout, nullptr);
		vkDestroyPipelineCache(vulkanDevice->logicalDevice, pipelineCache, nullptr);
		vkDestroyPipeline(vulkanDevice->logicalDevice, pipeline, nullptr);
		vkDestroyRenderPass(vulkanDevice->logicalDevice, renderPass, nullptr);
		vkDestroyCommandPool(vulkanDevice->logicalDevice, commandPool, nullptr);
	}

	// Prepare all vulkan resources required to render the font
	// The text overlay uses separate resources for descriptors (pool, sets, layouts), pipelines and command buffers
	void prepareResources()
	{
		const uint32_t fontWidth = STB_FONT_consolas_24_latin1_BITMAP_WIDTH;
		const uint32_t fontHeight = STB_FONT_consolas_24_latin1_BITMAP_WIDTH;

		static unsigned char font24pixels[fontWidth][fontHeight];
		stb_font_consolas_24_latin1(stbFontData, font24pixels, fontHeight);

		// Command buffer

		// Pool
		VkCommandPoolCreateInfo cmdPoolInfo = {};
		cmdPoolInfo.sType = VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO;
		cmdPoolInfo.queueFamilyIndex = vulkanDevice->queueFamilyIndices.graphics;
		cmdPoolInfo.flags = VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT;
		VK_CHECK_RESULT(vkCreateCommandPool(vulkanDevice->logicalDevice, &cmdPoolInfo, nullptr, &commandPool));

		VkCommandBufferAllocateInfo cmdBufAllocateInfo =
			vks::initializers::commandBufferAllocateInfo(
				commandPool,
				VK_COMMAND_BUFFER_LEVEL_PRIMARY,
				(uint32_t)cmdBuffers.size());

		VK_CHECK_RESULT(vkAllocateCommandBuffers(vulkanDevice->logicalDevice, &cmdBufAllocateInfo, cmdBuffers.data()));

		// Vertex buffer
		VkDeviceSize bufferSize = TEXTOVERLAY_MAX_CHAR_COUNT * sizeof(glm::vec4);

		VkBufferCreateInfo bufferInfo = vks::initializers::bufferCreateInfo(VK_BUFFER_USAGE_VERTEX_BUFFER_BIT, bufferSize);
		VK_CHECK_RESULT(vkCreateBuffer(vulkanDevice->logicalDevice, &bufferInfo, nullptr, &buffer));

		VkMemoryRequirements memReqs;
		VkMemoryAllocateInfo allocInfo = vks::initializers::memoryAllocateInfo();

		vkGetBufferMemoryRequirements(vulkanDevice->logicalDevice, buffer, &memReqs);
		allocInfo.allocationSize = memReqs.size;
		allocInfo.memoryTypeIndex = vulkanDevice->getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT);

		VK_CHECK_RESULT(vkAllocateMemory(vulkanDevice->logicalDevice, &allocInfo, nullptr, &memory));
		VK_CHECK_RESULT(vkBindBufferMemory(vulkanDevice->logicalDevice, buffer, memory, 0));

		// Font texture
		VkImageCreateInfo imageInfo = vks::initializers::imageCreateInfo();
		imageInfo.imageType = VK_IMAGE_TYPE_2D;
		imageInfo.format = VK_FORMAT_R8_UNORM;
		imageInfo.extent.width = fontWidth;
		imageInfo.extent.height = fontHeight;
		imageInfo.extent.depth = 1;
		imageInfo.mipLevels = 1;
		imageInfo.arrayLayers = 1;
		imageInfo.samples = VK_SAMPLE_COUNT_1_BIT;
		imageInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
		imageInfo.usage = VK_IMAGE_USAGE_TRANSFER_DST_BIT | VK_IMAGE_USAGE_SAMPLED_BIT;
		imageInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
		imageInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;

		VK_CHECK_RESULT(vkCreateImage(vulkanDevice->logicalDevice, &imageInfo, nullptr, &image));

		vkGetImageMemoryRequirements(vulkanDevice->logicalDevice, image, &memReqs);
		allocInfo.allocationSize = memReqs.size;
		allocInfo.memoryTypeIndex = vulkanDevice->getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);

		VK_CHECK_RESULT(vkAllocateMemory(vulkanDevice->logicalDevice, &allocInfo, nullptr, &imageMemory));
		VK_CHECK_RESULT(vkBindImageMemory(vulkanDevice->logicalDevice, image, imageMemory, 0));

		// Staging

		struct {
			VkDeviceMemory memory;
			VkBuffer buffer;
		} stagingBuffer;

		VkBufferCreateInfo bufferCreateInfo = vks::initializers::bufferCreateInfo();
		bufferCreateInfo.size = allocInfo.allocationSize;
		bufferCreateInfo.usage = VK_BUFFER_USAGE_TRANSFER_SRC_BIT;
		bufferCreateInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;

		VK_CHECK_RESULT(vkCreateBuffer(vulkanDevice->logicalDevice, &bufferCreateInfo, nullptr, &stagingBuffer.buffer));

		// Get memory requirements for the staging buffer (alignment, memory type bits)
		vkGetBufferMemoryRequirements(vulkanDevice->logicalDevice, stagingBuffer.buffer, &memReqs);

		allocInfo.allocationSize = memReqs.size;
		// Get memory type index for a host visible buffer
		allocInfo.memoryTypeIndex = vulkanDevice->getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT);

		VK_CHECK_RESULT(vkAllocateMemory(vulkanDevice->logicalDevice, &allocInfo, nullptr, &stagingBuffer.memory));
		VK_CHECK_RESULT(vkBindBufferMemory(vulkanDevice->logicalDevice, stagingBuffer.buffer, stagingBuffer.memory, 0));

		uint8_t *data;
		VK_CHECK_RESULT(vkMapMemory(vulkanDevice->logicalDevice, stagingBuffer.memory, 0, allocInfo.allocationSize, 0, (void **)&data));
		// Size of the font texture is WIDTH * HEIGHT * 1 byte (only one channel)
		memcpy(data, &font24pixels[0][0], fontWidth * fontHeight);
		vkUnmapMemory(vulkanDevice->logicalDevice, stagingBuffer.memory);

		// Copy to image

		VkCommandBuffer copyCmd;
		cmdBufAllocateInfo.commandBufferCount = 1;
		VK_CHECK_RESULT(vkAllocateCommandBuffers(vulkanDevice->logicalDevice, &cmdBufAllocateInfo, &copyCmd));

		VkCommandBufferBeginInfo cmdBufInfo = vks::initializers::commandBufferBeginInfo();
		VK_CHECK_RESULT(vkBeginCommandBuffer(copyCmd, &cmdBufInfo));

		// Prepare for transfer
		vks::tools::setImageLayout(
			copyCmd,
			image,
			VK_IMAGE_ASPECT_COLOR_BIT,
			VK_IMAGE_LAYOUT_UNDEFINED,
			VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL);

		VkBufferImageCopy bufferCopyRegion = {};
		bufferCopyRegion.imageSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
		bufferCopyRegion.imageSubresource.mipLevel = 0;
		bufferCopyRegion.imageSubresource.layerCount = 1;
		bufferCopyRegion.imageExtent.width = fontWidth;
		bufferCopyRegion.imageExtent.height = fontHeight;
		bufferCopyRegion.imageExtent.depth = 1;

		vkCmdCopyBufferToImage(
			copyCmd,
			stagingBuffer.buffer,
			image,
			VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
			1,
			&bufferCopyRegion
			);

		// Prepare for shader read
		vks::tools::setImageLayout(
			copyCmd,
			image,
			VK_IMAGE_ASPECT_COLOR_BIT,
			VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
			VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL);

		VK_CHECK_RESULT(vkEndCommandBuffer(copyCmd));

		VkSubmitInfo submitInfo = vks::initializers::submitInfo();
		submitInfo.commandBufferCount = 1;
		submitInfo.pCommandBuffers = &copyCmd;

		VK_CHECK_RESULT(vkQueueSubmit(queue, 1, &submitInfo, VK_NULL_HANDLE));
		VK_CHECK_RESULT(vkQueueWaitIdle(queue));

		vkFreeCommandBuffers(vulkanDevice->logicalDevice, commandPool, 1, &copyCmd);
		vkFreeMemory(vulkanDevice->logicalDevice, stagingBuffer.memory, nullptr);
		vkDestroyBuffer(vulkanDevice->logicalDevice, stagingBuffer.buffer, nullptr);

		VkImageViewCreateInfo imageViewInfo = vks::initializers::imageViewCreateInfo();
		imageViewInfo.image = image;
		imageViewInfo.viewType = VK_IMAGE_VIEW_TYPE_2D;
		imageViewInfo.format = imageInfo.format;
		imageViewInfo.components = { VK_COMPONENT_SWIZZLE_R, VK_COMPONENT_SWIZZLE_G, VK_COMPONENT_SWIZZLE_B,	VK_COMPONENT_SWIZZLE_A };
		imageViewInfo.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
		VK_CHECK_RESULT(vkCreateImageView(vulkanDevice->logicalDevice, &imageViewInfo, nullptr, &view));

		// Sampler
		VkSamplerCreateInfo samplerInfo = vks::initializers::samplerCreateInfo();
		samplerInfo.magFilter = VK_FILTER_LINEAR;
		samplerInfo.minFilter = VK_FILTER_LINEAR;
		samplerInfo.mipmapMode = VK_SAMPLER_MIPMAP_MODE_LINEAR;
		samplerInfo.addressModeU = VK_SAMPLER_ADDRESS_MODE_REPEAT;
		samplerInfo.addressModeV = VK_SAMPLER_ADDRESS_MODE_REPEAT;
		samplerInfo.addressModeW = VK_SAMPLER_ADDRESS_MODE_REPEAT;
		samplerInfo.mipLodBias = 0.0f;
		samplerInfo.compareOp = VK_COMPARE_OP_NEVER;
		samplerInfo.minLod = 0.0f;
		samplerInfo.maxLod = 1.0f;
		samplerInfo.borderColor = VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE;
		VK_CHECK_RESULT(vkCreateSampler(vulkanDevice->logicalDevice, &samplerInfo, nullptr, &sampler));

		// Descriptor
		// Font uses a separate descriptor pool
		std::array<VkDescriptorPoolSize, 1> poolSizes;
		poolSizes[0] = vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1);

		VkDescriptorPoolCreateInfo descriptorPoolInfo =
			vks::initializers::descriptorPoolCreateInfo(
				static_cast<uint32_t>(poolSizes.size()),
				poolSizes.data(),
				1);

		VK_CHECK_RESULT(vkCreateDescriptorPool(vulkanDevice->logicalDevice, &descriptorPoolInfo, nullptr, &descriptorPool));

		// Descriptor set layout
		std::array<VkDescriptorSetLayoutBinding, 1> setLayoutBindings;
		setLayoutBindings[0] = vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, VK_SHADER_STAGE_FRAGMENT_BIT, 0);

		VkDescriptorSetLayoutCreateInfo descriptorSetLayoutInfo =
			vks::initializers::descriptorSetLayoutCreateInfo(
				setLayoutBindings.data(),
				static_cast<uint32_t>(setLayoutBindings.size()));
		VK_CHECK_RESULT(vkCreateDescriptorSetLayout(vulkanDevice->logicalDevice, &descriptorSetLayoutInfo, nullptr, &descriptorSetLayout));

		// Pipeline layout
		VkPipelineLayoutCreateInfo pipelineLayoutInfo =
			vks::initializers::pipelineLayoutCreateInfo(
				&descriptorSetLayout,
				1);
		VK_CHECK_RESULT(vkCreatePipelineLayout(vulkanDevice->logicalDevice, &pipelineLayoutInfo, nullptr, &pipelineLayout));

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

		VK_CHECK_RESULT(vkAllocateDescriptorSets(vulkanDevice->logicalDevice, &descriptorSetAllocInfo, &descriptorSet));

		VkDescriptorImageInfo texDescriptor =
			vks::initializers::descriptorImageInfo(
				sampler,
				view,
				VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL);

		std::array<VkWriteDescriptorSet, 1> writeDescriptorSets;
		writeDescriptorSets[0] = vks::initializers::writeDescriptorSet(descriptorSet, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 0, &texDescriptor);
		vkUpdateDescriptorSets(vulkanDevice->logicalDevice, static_cast<uint32_t>(writeDescriptorSets.size()), writeDescriptorSets.data(), 0, NULL);

		// Pipeline cache
		VkPipelineCacheCreateInfo pipelineCacheCreateInfo = {};
		pipelineCacheCreateInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_CACHE_CREATE_INFO;
		VK_CHECK_RESULT(vkCreatePipelineCache(vulkanDevice->logicalDevice, &pipelineCacheCreateInfo, nullptr, &pipelineCache));
	}

	// Prepare a separate pipeline for the font rendering decoupled from the main application
	void preparePipeline()
	{
		// Enable blending, using alpha from red channel of the font texture (see text.frag)
		VkPipelineColorBlendAttachmentState blendAttachmentState{};
		blendAttachmentState.blendEnable = VK_TRUE;
		blendAttachmentState.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;
		blendAttachmentState.srcColorBlendFactor = VK_BLEND_FACTOR_SRC_ALPHA;
		blendAttachmentState.dstColorBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA;
		blendAttachmentState.colorBlendOp = VK_BLEND_OP_ADD;
		blendAttachmentState.srcAlphaBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA;
		blendAttachmentState.dstAlphaBlendFactor = VK_BLEND_FACTOR_ZERO;
		blendAttachmentState.alphaBlendOp = VK_BLEND_OP_ADD;

		VkPipelineInputAssemblyStateCreateInfo inputAssemblyState = vks::initializers::pipelineInputAssemblyStateCreateInfo(VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP, 0, VK_FALSE);
		VkPipelineRasterizationStateCreateInfo rasterizationState = vks::initializers::pipelineRasterizationStateCreateInfo(VK_POLYGON_MODE_FILL, VK_CULL_MODE_BACK_BIT, VK_FRONT_FACE_CLOCKWISE, 0);
		VkPipelineColorBlendStateCreateInfo colorBlendState = vks::initializers::pipelineColorBlendStateCreateInfo(1, &blendAttachmentState);
		VkPipelineDepthStencilStateCreateInfo depthStencilState = vks::initializers::pipelineDepthStencilStateCreateInfo(VK_TRUE, VK_TRUE, VK_COMPARE_OP_LESS_OR_EQUAL);
		VkPipelineViewportStateCreateInfo viewportState = vks::initializers::pipelineViewportStateCreateInfo(1, 1, 0);
		VkPipelineMultisampleStateCreateInfo multisampleState = vks::initializers::pipelineMultisampleStateCreateInfo(VK_SAMPLE_COUNT_1_BIT, 0);
		std::vector<VkDynamicState> dynamicStateEnables = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };
		VkPipelineDynamicStateCreateInfo dynamicState = vks::initializers::pipelineDynamicStateCreateInfo(dynamicStateEnables);

		std::array<VkVertexInputBindingDescription, 2> vertexInputBindings = {
			vks::initializers::vertexInputBindingDescription(0, sizeof(glm::vec4), VK_VERTEX_INPUT_RATE_VERTEX),
			vks::initializers::vertexInputBindingDescription(1, sizeof(glm::vec4), VK_VERTEX_INPUT_RATE_VERTEX),
		};
		std::array<VkVertexInputAttributeDescription, 2> vertexInputAttributes = {
			vks::initializers::vertexInputAttributeDescription(0, 0, VK_FORMAT_R32G32_SFLOAT, 0),					// Location 0: Position
			vks::initializers::vertexInputAttributeDescription(1, 1, VK_FORMAT_R32G32_SFLOAT, sizeof(glm::vec2)),	// Location 1: 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();

		VkGraphicsPipelineCreateInfo pipelineCreateInfo = vks::initializers::pipelineCreateInfo(pipelineLayout, renderPass, 0);
		pipelineCreateInfo.pVertexInputState = &vertexInputState;
		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();

		VK_CHECK_RESULT(vkCreateGraphicsPipelines(vulkanDevice->logicalDevice, pipelineCache, 1, &pipelineCreateInfo, nullptr, &pipeline));
	}

	// Prepare a separate render pass for rendering the text as an overlay
	void prepareRenderPass()
	{
		VkAttachmentDescription attachments[2] = {};

		// Color attachment
		attachments[0].format = colorFormat;
		attachments[0].samples = VK_SAMPLE_COUNT_1_BIT;
		// Don't clear the framebuffer (like the renderpass from the example does)
		attachments[0].loadOp = VK_ATTACHMENT_LOAD_OP_LOAD;
		attachments[0].storeOp = VK_ATTACHMENT_STORE_OP_STORE;
		attachments[0].stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
		attachments[0].stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
		attachments[0].initialLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;
		attachments[0].finalLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;

		// Depth attachment
		attachments[1].format = depthFormat;
		attachments[1].samples = VK_SAMPLE_COUNT_1_BIT;
		attachments[1].loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
		attachments[1].storeOp = VK_ATTACHMENT_STORE_OP_STORE;
		attachments[1].stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
		attachments[1].stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
		attachments[1].initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
		attachments[1].finalLayout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;

		VkAttachmentReference colorReference = {};
		colorReference.attachment = 0;
		colorReference.layout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;

		VkAttachmentReference depthReference = {};
		depthReference.attachment = 1;
		depthReference.layout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;

		// Use subpass dependencies for image layout transitions
		VkSubpassDependency subpassDependencies[2] = {};

		// Transition from final to initial (VK_SUBPASS_EXTERNAL refers to all commands executed outside of the actual renderpass)
		subpassDependencies[0].srcSubpass = VK_SUBPASS_EXTERNAL;
		subpassDependencies[0].dstSubpass = 0;
		subpassDependencies[0].srcStageMask = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
		subpassDependencies[0].dstStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
		subpassDependencies[0].srcAccessMask = VK_ACCESS_MEMORY_READ_BIT;
		subpassDependencies[0].dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
		subpassDependencies[0].dependencyFlags = VK_DEPENDENCY_BY_REGION_BIT;

		// Transition from initial to final
		subpassDependencies[1].srcSubpass = 0;
		subpassDependencies[1].dstSubpass = VK_SUBPASS_EXTERNAL;
		subpassDependencies[1].srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
		subpassDependencies[1].dstStageMask = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
		subpassDependencies[1].srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
		subpassDependencies[1].dstAccessMask = VK_ACCESS_MEMORY_READ_BIT;
		subpassDependencies[1].dependencyFlags = VK_DEPENDENCY_BY_REGION_BIT;

		VkSubpassDescription subpassDescription = {};
		subpassDescription.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
		subpassDescription.flags = 0;
		subpassDescription.inputAttachmentCount = 0;
		subpassDescription.pInputAttachments = NULL;
		subpassDescription.colorAttachmentCount = 1;
		subpassDescription.pColorAttachments = &colorReference;
		subpassDescription.pResolveAttachments = NULL;
		subpassDescription.pDepthStencilAttachment = &depthReference;
		subpassDescription.preserveAttachmentCount = 0;
		subpassDescription.pPreserveAttachments = NULL;

		VkRenderPassCreateInfo renderPassInfo = {};
		renderPassInfo.sType = VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO;
		renderPassInfo.pNext = NULL;
		renderPassInfo.attachmentCount = 2;
		renderPassInfo.pAttachments = attachments;
		renderPassInfo.subpassCount = 1;
		renderPassInfo.pSubpasses = &subpassDescription;
		renderPassInfo.dependencyCount = 2;
		renderPassInfo.pDependencies = subpassDependencies;

		VK_CHECK_RESULT(vkCreateRenderPass(vulkanDevice->logicalDevice, &renderPassInfo, nullptr, &renderPass));
	}

	// Map buffer
	void beginTextUpdate()
	{
		VK_CHECK_RESULT(vkMapMemory(vulkanDevice->logicalDevice, memory, 0, VK_WHOLE_SIZE, 0, (void **)&mapped));
		numLetters = 0;
	}

	// Add text to the current buffer
	// todo : drop shadow? color attribute?
	void addText(std::string text, float x, float y, TextAlign align)
	{
		const uint32_t firstChar = STB_FONT_consolas_24_latin1_FIRST_CHAR;

		assert(mapped != nullptr);

		const float charW = 1.5f / *frameBufferWidth;
		const float charH = 1.5f / *frameBufferHeight;

		float fbW = (float)*frameBufferWidth;
		float fbH = (float)*frameBufferHeight;
		x = (x / fbW * 2.0f) - 1.0f;
		y = (y / fbH * 2.0f) - 1.0f;

		// Calculate text width
		float textWidth = 0;
		for (auto letter : text)
		{
			stb_fontchar *charData = &stbFontData[(uint32_t)letter - firstChar];
			textWidth += charData->advance * charW;
		}

		switch (align)
		{
			case alignRight:
				x -= textWidth;
				break;
			case alignCenter:
				x -= textWidth / 2.0f;
				break;
			case alignLeft:
				break;
		}

		// Generate a uv mapped quad per char in the new text
		for (auto letter : text)
		{
			stb_fontchar *charData = &stbFontData[(uint32_t)letter - firstChar];

			mapped->x = (x + (float)charData->x0 * charW);
			mapped->y = (y + (float)charData->y0 * charH);
			mapped->z = charData->s0;
			mapped->w = charData->t0;
			mapped++;

			mapped->x = (x + (float)charData->x1 * charW);
			mapped->y = (y + (float)charData->y0 * charH);
			mapped->z = charData->s1;
			mapped->w = charData->t0;
			mapped++;

			mapped->x = (x + (float)charData->x0 * charW);
			mapped->y = (y + (float)charData->y1 * charH);
			mapped->z = charData->s0;
			mapped->w = charData->t1;
			mapped++;

			mapped->x = (x + (float)charData->x1 * charW);
			mapped->y = (y + (float)charData->y1 * charH);
			mapped->z = charData->s1;
			mapped->w = charData->t1;
			mapped++;

			x += charData->advance * charW;

			numLetters++;
		}
	}

	// Unmap buffer and update command buffers
	void endTextUpdate()
	{
		vkUnmapMemory(vulkanDevice->logicalDevice, memory);
		mapped = nullptr;
		updateCommandBuffers();
	}

	// Needs to be called by the application
	void updateCommandBuffers()
	{
		VkCommandBufferBeginInfo cmdBufInfo = vks::initializers::commandBufferBeginInfo();

		VkClearValue clearValues[2];
		clearValues[1].color = { { 0.0f, 0.0f, 0.0f, 0.0f } };

		VkRenderPassBeginInfo renderPassBeginInfo = vks::initializers::renderPassBeginInfo();
		renderPassBeginInfo.renderPass = renderPass;
		renderPassBeginInfo.renderArea.extent.width = *frameBufferWidth;
		renderPassBeginInfo.renderArea.extent.height = *frameBufferHeight;
		renderPassBeginInfo.clearValueCount = 2;
		renderPassBeginInfo.pClearValues = clearValues;

		for (int32_t i = 0; i < cmdBuffers.size(); ++i)
		{
			renderPassBeginInfo.framebuffer = *frameBuffers[i];

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

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

			VkViewport viewport = vks::initializers::viewport((float)*frameBufferWidth, (float)*frameBufferHeight, 0.0f, 1.0f);
			vkCmdSetViewport(cmdBuffers[i], 0, 1, &viewport);

			VkRect2D scissor = vks::initializers::rect2D(*frameBufferWidth, *frameBufferHeight, 0, 0);
			vkCmdSetScissor(cmdBuffers[i], 0, 1, &scissor);

			vkCmdBindPipeline(cmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
			vkCmdBindDescriptorSets(cmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSet, 0, NULL);

			VkDeviceSize offsets = 0;
			vkCmdBindVertexBuffers(cmdBuffers[i], 0, 1, &buffer, &offsets);
			vkCmdBindVertexBuffers(cmdBuffers[i], 1, 1, &buffer, &offsets);
			for (uint32_t j = 0; j < numLetters; j++)
			{
				vkCmdDraw(cmdBuffers[i], 4, 1, j * 4, 0);
			}


			vkCmdEndRenderPass(cmdBuffers[i]);

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

/*
	Vulkan example main class
*/
class VulkanExample : public VulkanExampleBase
{
public:
	TextOverlay *textOverlay = nullptr;

	vkglTF::Model model;

	vks::Buffer uniformBuffer;

	struct UBOVS {
		glm::mat4 projection;
		glm::mat4 modelView;
		glm::vec4 lightPos = glm::vec4(0.0f, 0.0f, 0.0f, 1.0f);
	} uboVS;

	VkPipelineLayout pipelineLayout;
	VkPipeline pipeline;

	VkDescriptorSetLayout descriptorSetLayout;
	VkDescriptorSet descriptorSet;

	VulkanExample() : VulkanExampleBase(ENABLE_VALIDATION)
	{
		title = "Vulkan Example - Text overlay";
		camera.type = Camera::CameraType::lookat;
		camera.setPosition(glm::vec3(0.0f, 0.0f, -2.5f));
		camera.setRotation(glm::vec3(-25.0f, -0.0f, 0.0f));
		camera.setPerspective(60.0f, (float)width / (float)height, 0.1f, 256.0f);
		settings.overlay = false;
	}

	~VulkanExample()
	{
		vkDestroyPipeline(device, pipeline, nullptr);
		vkDestroyPipelineLayout(device, pipelineLayout, nullptr);
		vkDestroyDescriptorSetLayout(device, descriptorSetLayout, nullptr);
		uniformBuffer.destroy();
		delete(textOverlay);
	}

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

		VkClearValue clearValues[3];

		clearValues[0].color = { { 0.0f, 0.0f, 0.2f, 1.0f } };
		clearValues[1].depthStencil = { 1.0f, 0 };

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

		for (int32_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);

			vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSet, 0, nullptr);
			model.draw(drawCmdBuffers[i]);

			vkCmdEndRenderPass(drawCmdBuffers[i]);

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

		vkQueueWaitIdle(queue);
	}

	// Update the text buffer displayed by the text overlay
	void updateTextOverlay(void)
	{
		textOverlay->beginTextUpdate();

		textOverlay->addText(title, 5.0f, 5.0f, TextOverlay::alignLeft);

		std::stringstream ss;
		ss << std::fixed << std::setprecision(2) << (frameTimer * 1000.0f) << "ms (" << lastFPS << " fps)";
		textOverlay->addText(ss.str(), 5.0f, 25.0f, TextOverlay::alignLeft);

		textOverlay->addText(deviceProperties.deviceName, 5.0f, 45.0f, TextOverlay::alignLeft);

		// Display current model view matrix
		textOverlay->addText("model view matrix", (float)width, 5.0f, TextOverlay::alignRight);

		for (uint32_t i = 0; i < 4; i++)
		{
			ss.str("");
			ss << std::fixed << std::setprecision(2) << std::showpos;
			ss << uboVS.modelView[0][i] << " " << uboVS.modelView[1][i] << " " << uboVS.modelView[2][i] << " " << uboVS.modelView[3][i];
			textOverlay->addText(ss.str(), (float)width, 25.0f + (float)i * 20.0f, TextOverlay::alignRight);
		}

		glm::vec3 projected = glm::project(glm::vec3(0.0f), uboVS.modelView, uboVS.projection, glm::vec4(0, 0, (float)width, (float)height));
		textOverlay->addText("A cube", projected.x, projected.y, TextOverlay::alignCenter);

#if defined(__ANDROID__)
#else
		textOverlay->addText("Press \"space\" to toggle text overlay", 5.0f, 65.0f, TextOverlay::alignLeft);
		textOverlay->addText("Hold middle mouse button and drag to move", 5.0f, 85.0f, TextOverlay::alignLeft);
#endif
		textOverlay->endTextUpdate();
	}

	void loadAssets()
	{
		const uint32_t glTFLoadingFlags = vkglTF::FileLoadingFlags::PreTransformVertices | vkglTF::FileLoadingFlags::PreMultiplyVertexColors | vkglTF::FileLoadingFlags::FlipY;
		model.loadFromFile(getAssetPath() + "models/cube.gltf", vulkanDevice, queue, glTFLoadingFlags);
	}

	void setupDescriptorPool()
	{
		std::vector<VkDescriptorPoolSize> poolSizes = {
			vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 2),
		};

		VkDescriptorPoolCreateInfo descriptorPoolInfo =
			vks::initializers::descriptorPoolCreateInfo(poolSizes, 2);
		VK_CHECK_RESULT(vkCreateDescriptorPool(device, &descriptorPoolInfo, nullptr, &descriptorPool));
	}

	void setupDescriptorSetLayout()
	{
		std::vector<VkDescriptorSetLayoutBinding> setLayoutBindings = {
			// Binding 0: Vertex shader uniform buffer
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, VK_SHADER_STAGE_VERTEX_BIT, 0),
		};
		VkDescriptorSetLayoutCreateInfo descriptorLayout =
			vks::initializers::descriptorSetLayoutCreateInfo(setLayoutBindings);
		VK_CHECK_RESULT(vkCreateDescriptorSetLayout(device, &descriptorLayout, nullptr, &descriptorSetLayout));

		VkPipelineLayoutCreateInfo pPipelineLayoutCreateInfo =
			vks::initializers::pipelineLayoutCreateInfo(&descriptorSetLayout, 1);
		VK_CHECK_RESULT(vkCreatePipelineLayout(device, &pPipelineLayoutCreateInfo, nullptr, &pipelineLayout));
	}

	void setupDescriptorSet()
	{
		VkDescriptorSetAllocateInfo allocInfo =
			vks::initializers::descriptorSetAllocateInfo(descriptorPool, &descriptorSetLayout, 1);
		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &allocInfo, &descriptorSet));
		std::vector<VkWriteDescriptorSet> writeDescriptorSets = {
			// Binding 0: Vertex shader uniform buffer
			vks::initializers::writeDescriptorSet(descriptorSet, VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 0, &uniformBuffer.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_BACK_BIT, VK_FRONT_FACE_COUNTER_CLOCKWISE, 0);
		VkPipelineColorBlendAttachmentState blendAttachmentState = vks::initializers::pipelineColorBlendAttachmentState(0xf, VK_FALSE);
		VkPipelineColorBlendStateCreateInfo colorBlendState = vks::initializers::pipelineColorBlendStateCreateInfo(1, &blendAttachmentState);
		VkPipelineDepthStencilStateCreateInfo depthStencilState = vks::initializers::pipelineDepthStencilStateCreateInfo(VK_TRUE, VK_TRUE, VK_COMPARE_OP_LESS_OR_EQUAL);
		VkPipelineViewportStateCreateInfo viewportState = vks::initializers::pipelineViewportStateCreateInfo(1, 1, 0);
		VkPipelineMultisampleStateCreateInfo multisampleState = vks::initializers::pipelineMultisampleStateCreateInfo(VK_SAMPLE_COUNT_1_BIT, 0);
		std::vector<VkDynamicState> dynamicStateEnables = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };
		VkPipelineDynamicStateCreateInfo dynamicState = vks::initializers::pipelineDynamicStateCreateInfo(dynamicStateEnables);
		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 = static_cast<uint32_t>(shaderStages.size());
		pipelineCI.pStages = shaderStages.data();
		pipelineCI.pVertexInputState = vkglTF::Vertex::getPipelineVertexInputState({vkglTF::VertexComponent::Position, vkglTF::VertexComponent::Normal, vkglTF::VertexComponent::UV});

		shaderStages[0] = loadShader(getShadersPath() + "textoverlay/mesh.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
		shaderStages[1] = loadShader(getShadersPath() + "textoverlay/mesh.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCI, nullptr, &pipeline));
	}

	// Prepare and initialize uniform buffer containing shader uniforms
	void prepareUniformBuffers()
	{
		// Vertex shader uniform buffer block
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&uniformBuffer,
			sizeof(uboVS)));

		// Map persistent
		VK_CHECK_RESULT(uniformBuffer.map());

		updateUniformBuffers();
	}

	void updateUniformBuffers()
	{
		uboVS.projection = camera.matrices.perspective;
		uboVS.modelView = camera.matrices.view * glm::scale(glm::mat4(1.0f), glm::vec3(0.1f));
		memcpy(uniformBuffer.mapped, &uboVS, sizeof(uboVS));
	}

	void prepareTextOverlay()
	{
		// Load the text rendering shaders
		std::vector<VkPipelineShaderStageCreateInfo> shaderStages;
		shaderStages.push_back(loadShader(getShadersPath() + "textoverlay/text.vert.spv", VK_SHADER_STAGE_VERTEX_BIT));
		shaderStages.push_back(loadShader(getShadersPath() + "textoverlay/text.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT));

		textOverlay = new TextOverlay(
			vulkanDevice,
			queue,
			frameBuffers,
			swapChain.colorFormat,
			depthFormat,
			&width,
			&height,
			shaderStages
			);
		updateTextOverlay();
	}

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

		std::vector<VkCommandBuffer> commandBuffers = {
			drawCmdBuffers[currentBuffer]
		};
		if (textOverlay->visible) {
			commandBuffers.push_back(textOverlay->cmdBuffers[currentBuffer]);
		}

		// Command buffer to be submitted to the queue
		submitInfo.commandBufferCount = static_cast<uint32_t>(commandBuffers.size());
		submitInfo.pCommandBuffers = commandBuffers.data();

		// Submit to queue
		VK_CHECK_RESULT(vkQueueSubmit(queue, 1, &submitInfo, VK_NULL_HANDLE));

		VulkanExampleBase::submitFrame();
	}

	void prepare()
	{
		VulkanExampleBase::prepare();
		loadAssets();
		prepareUniformBuffers();
		setupDescriptorSetLayout();
		preparePipelines();
		setupDescriptorPool();
		setupDescriptorSet();
		buildCommandBuffers();
		prepareTextOverlay();
		prepared = true;
	}

	virtual void render()
	{
		if (!prepared)
			return;
		draw();
		if (camera.updated)
		{
			updateUniformBuffers();
		}
		if (frameCounter == 0)
		{
			vkDeviceWaitIdle(device);
			updateTextOverlay();
		}
	}

	virtual void windowResized()
	{
		// SRS - Recreate text overlay resources in case number of swapchain images has changed on resize
		delete textOverlay;
		prepareTextOverlay();
	}

	virtual void viewChanged()
	{
		updateUniformBuffers();
		updateTextOverlay();
	}

#if !defined(__ANDROID__)
	virtual void keyPressed(uint32_t keyCode)
	{
		switch (keyCode)
		{
		case KEY_KPADD:
		case KEY_SPACE:
			textOverlay->visible = !textOverlay->visible;
		}
	}
#endif
};

VULKAN_EXAMPLE_MAIN()