procedural-3d-engine/base/vulkantextoverlay.hpp

/*
* Text overlay class for displaying debug information
*
* Copyright (C) 2016 by Sascha Willems - www.saschawillems.de
*
* This code is licensed under the MIT license (MIT) (http://opensource.org/licenses/MIT)
*/

#pragma once

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <vector>
#include <sstream>
#include <iomanip>

#include <vulkan/vulkan.h>
#include "vulkantools.h"

#include "../external/stb/stb_font_consolas_24_latin1.inl"

// Defines for the STB font used
// STB font files can be found at http://nothings.org/stb/font/
#define STB_FONT_NAME stb_font_consolas_24_latin1
#define STB_FONT_WIDTH STB_FONT_consolas_24_latin1_BITMAP_WIDTH
#define STB_FONT_HEIGHT STB_FONT_consolas_24_latin1_BITMAP_HEIGHT 
#define STB_FIRST_CHAR STB_FONT_consolas_24_latin1_FIRST_CHAR
#define STB_NUM_CHARS STB_FONT_consolas_24_latin1_NUM_CHARS

// Max. number of chars the text overlay buffer can hold
#define MAX_CHAR_COUNT 512

// Mostly self-contained text overlay class
// todo : comment
class VulkanTextOverlay
{
private:
	VkPhysicalDevice physicalDevice;
	VkDevice device;
	VkPhysicalDeviceMemoryProperties deviceMemoryProperties;
	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_NUM_CHARS];
	uint32_t numLetters;

	// Try to find appropriate memory type for a memory allocation
	uint32_t getMemoryType(uint32_t typeBits, VkFlags properties)
	{
		for (uint32_t i = 0; i < 32; i++)
		{
			if ((typeBits & 1) == 1)
			{
				if ((deviceMemoryProperties.memoryTypes[i].propertyFlags & properties) == properties)
				{
					return i;
				}
			}
			typeBits >>= 1;
		}

		// todo : throw error
		return 0;
	}
public:

	enum TextAlign { alignLeft, alignCenter, alignRight };

	bool visible = true;
	bool invalidated = false;

	std::vector<VkCommandBuffer> cmdBuffers;

	VulkanTextOverlay(
		VkPhysicalDevice physicalDevice,
		VkDevice device,
		VkQueue queue,
		std::vector<VkFramebuffer> &framebuffers,
		VkFormat colorformat,
		VkFormat depthformat,
		uint32_t *framebufferwidth,
		uint32_t *framebufferheight,
		std::vector<VkPipelineShaderStageCreateInfo> shaderstages)
	{
		this->physicalDevice = physicalDevice;
		this->device = device;
		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;

		vkGetPhysicalDeviceMemoryProperties(physicalDevice, &deviceMemoryProperties);
		cmdBuffers.resize(framebuffers.size());
		prepareResources();
		prepareRenderPass();
		preparePipeline();
	}

	~VulkanTextOverlay()
	{
		// Free up all Vulkan resources requested by the text overlay
		vkDestroySampler(device, sampler, nullptr);
		vkDestroyImage(device, image, nullptr);
		vkDestroyImageView(device, view, nullptr);
		vkDestroyBuffer(device, buffer, nullptr);
		vkFreeMemory(device, memory, nullptr);
		vkFreeMemory(device, imageMemory, nullptr);
		vkDestroyDescriptorSetLayout(device, descriptorSetLayout, nullptr);
		vkDestroyDescriptorPool(device, descriptorPool, nullptr);
		vkDestroyPipelineLayout(device, pipelineLayout, nullptr);
		vkDestroyPipelineCache(device, pipelineCache, nullptr);
		vkDestroyPipeline(device, pipeline, nullptr);
		vkDestroyRenderPass(device, renderPass, nullptr);
		vkFreeCommandBuffers(device, commandPool, cmdBuffers.size(), cmdBuffers.data());
		vkDestroyCommandPool(device, 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()
	{
		static unsigned char font24pixels[STB_FONT_HEIGHT][STB_FONT_WIDTH];
		STB_FONT_NAME(stbFontData, font24pixels, STB_FONT_HEIGHT);

		// Command buffer

		// Pool
		VkCommandPoolCreateInfo cmdPoolInfo = {};
		cmdPoolInfo.sType = VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO;
		cmdPoolInfo.queueFamilyIndex = 0; // todo : pass from example base / swap chain
		cmdPoolInfo.flags = VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT;
		VK_CHECK_RESULT(vkCreateCommandPool(device, &cmdPoolInfo, nullptr, &commandPool));

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

		VK_CHECK_RESULT(vkAllocateCommandBuffers(device, &cmdBufAllocateInfo, cmdBuffers.data()));

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

		VkBufferCreateInfo bufferInfo = vkTools::initializers::bufferCreateInfo(VK_BUFFER_USAGE_VERTEX_BUFFER_BIT, bufferSize);
		VK_CHECK_RESULT(vkCreateBuffer(device, &bufferInfo, nullptr, &buffer));

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

		vkGetBufferMemoryRequirements(device, buffer, &memReqs);
		allocInfo.allocationSize = memReqs.size;
		allocInfo.memoryTypeIndex = getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT);

		VK_CHECK_RESULT(vkAllocateMemory(device, &allocInfo, nullptr, &memory));
		VK_CHECK_RESULT(vkBindBufferMemory(device, buffer, memory, 0));

		// Font texture
		VkImageCreateInfo imageInfo = vkTools::initializers::imageCreateInfo();
		imageInfo.imageType = VK_IMAGE_TYPE_2D;
		imageInfo.format = VK_FORMAT_R8_UNORM;
		imageInfo.extent.width = STB_FONT_WIDTH;
		imageInfo.extent.height = STB_FONT_HEIGHT;
		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_PREINITIALIZED;

		VK_CHECK_RESULT(vkCreateImage(device, &imageInfo, nullptr, &image));

		allocInfo.allocationSize = STB_FONT_WIDTH * STB_NUM_CHARS;
		allocInfo.memoryTypeIndex = getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);

		VK_CHECK_RESULT(vkAllocateMemory(device, &allocInfo, nullptr, &imageMemory));
		VK_CHECK_RESULT(vkBindImageMemory(device, image, imageMemory, 0));

		// Staging

		struct {
			VkDeviceMemory memory;
			VkBuffer buffer;
		} stagingBuffer;

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

		VK_CHECK_RESULT(vkCreateBuffer(device, &bufferCreateInfo, nullptr, &stagingBuffer.buffer));

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

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

		VK_CHECK_RESULT(vkAllocateMemory(device, &allocInfo, nullptr, &stagingBuffer.memory));
		VK_CHECK_RESULT(vkBindBufferMemory(device, stagingBuffer.buffer, stagingBuffer.memory, 0));

		uint8_t *data;
		VK_CHECK_RESULT(vkMapMemory(device, stagingBuffer.memory, 0, allocInfo.allocationSize, 0, (void **)&data));
		memcpy(data, &font24pixels[0][0], STB_FONT_WIDTH * STB_FONT_HEIGHT);
		vkUnmapMemory(device, stagingBuffer.memory);

		// Copy to image

		VkCommandBuffer copyCmd;
		cmdBufAllocateInfo.commandBufferCount = 1;
		VK_CHECK_RESULT(vkAllocateCommandBuffers(device, &cmdBufAllocateInfo, &copyCmd));

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

		// Prepare for transfer
		vkTools::setImageLayout(
			copyCmd,
			image,
			VK_IMAGE_ASPECT_COLOR_BIT,
			VK_IMAGE_LAYOUT_PREINITIALIZED,
			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 = STB_FONT_WIDTH;
		bufferCopyRegion.imageExtent.height = STB_FONT_HEIGHT;
		bufferCopyRegion.imageExtent.depth = 1;

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

		// Prepare for shader read
		vkTools::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 = vkTools::initializers::submitInfo();
		submitInfo.commandBufferCount = 1;
		submitInfo.pCommandBuffers = &copyCmd;

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

		vkFreeCommandBuffers(device, commandPool, 1, &copyCmd);
		vkFreeMemory(device, stagingBuffer.memory, nullptr);
		vkDestroyBuffer(device, stagingBuffer.buffer, nullptr);


		VkImageViewCreateInfo imageViewInfo = vkTools::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(device, &imageViewInfo, nullptr, &view));

		// Sampler
		VkSamplerCreateInfo samplerInfo = vkTools::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(device, &samplerInfo, nullptr, &sampler));

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

		VkDescriptorPoolCreateInfo descriptorPoolInfo =
			vkTools::initializers::descriptorPoolCreateInfo(
				poolSizes.size(),
				poolSizes.data(),
				1);

		VK_CHECK_RESULT(vkCreateDescriptorPool(device, &descriptorPoolInfo, nullptr, &descriptorPool));

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

		VkDescriptorSetLayoutCreateInfo descriptorSetLayoutInfo =
			vkTools::initializers::descriptorSetLayoutCreateInfo(
				setLayoutBindings.data(),
				setLayoutBindings.size());

		VK_CHECK_RESULT(vkCreateDescriptorSetLayout(device, &descriptorSetLayoutInfo, nullptr, &descriptorSetLayout));

		// Pipeline layout
		VkPipelineLayoutCreateInfo pipelineLayoutInfo =
			vkTools::initializers::pipelineLayoutCreateInfo(
				&descriptorSetLayout,
				1);

		VK_CHECK_RESULT(vkCreatePipelineLayout(device, &pipelineLayoutInfo, nullptr, &pipelineLayout));

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

		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &descriptorSetAllocInfo, &descriptorSet));

		VkDescriptorImageInfo texDescriptor =
			vkTools::initializers::descriptorImageInfo(
				sampler,
				view,
				VK_IMAGE_LAYOUT_GENERAL);

		std::array<VkWriteDescriptorSet, 1> writeDescriptorSets;
		writeDescriptorSets[0] = vkTools::initializers::writeDescriptorSet(descriptorSet, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 0, &texDescriptor);
		vkUpdateDescriptorSets(device, writeDescriptorSets.size(), writeDescriptorSets.data(), 0, NULL);

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

	// Prepare a separate pipeline for the font rendering decoupled from the main application
	void preparePipeline()
	{
		VkPipelineInputAssemblyStateCreateInfo inputAssemblyState =
			vkTools::initializers::pipelineInputAssemblyStateCreateInfo(
				VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP,
				0,
				VK_FALSE);

		VkPipelineRasterizationStateCreateInfo rasterizationState =
			vkTools::initializers::pipelineRasterizationStateCreateInfo(
				VK_POLYGON_MODE_FILL,
				VK_CULL_MODE_BACK_BIT,
				VK_FRONT_FACE_CLOCKWISE,
				0);

		// Enable blending
		VkPipelineColorBlendAttachmentState blendAttachmentState =
			vkTools::initializers::pipelineColorBlendAttachmentState(0xf, VK_TRUE);

		blendAttachmentState.srcColorBlendFactor = VK_BLEND_FACTOR_ONE;
		blendAttachmentState.dstColorBlendFactor = VK_BLEND_FACTOR_ONE;
		blendAttachmentState.colorBlendOp = VK_BLEND_OP_ADD;
		blendAttachmentState.srcAlphaBlendFactor = VK_BLEND_FACTOR_ONE;
		blendAttachmentState.dstAlphaBlendFactor = VK_BLEND_FACTOR_ONE;
		blendAttachmentState.alphaBlendOp = VK_BLEND_OP_ADD;
		blendAttachmentState.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;

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

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

		VkPipelineViewportStateCreateInfo viewportState =
			vkTools::initializers::pipelineViewportStateCreateInfo(1, 1, 0);

		VkPipelineMultisampleStateCreateInfo multisampleState =
			vkTools::initializers::pipelineMultisampleStateCreateInfo(
				VK_SAMPLE_COUNT_1_BIT,
				0);

		std::vector<VkDynamicState> dynamicStateEnables = {
			VK_DYNAMIC_STATE_VIEWPORT,
			VK_DYNAMIC_STATE_SCISSOR
		};

		VkPipelineDynamicStateCreateInfo dynamicState =
			vkTools::initializers::pipelineDynamicStateCreateInfo(
				dynamicStateEnables.data(),
				dynamicStateEnables.size(),
				0);

		std::array<VkVertexInputBindingDescription, 2> vertexBindings = {};
		vertexBindings[0] = vkTools::initializers::vertexInputBindingDescription(0, sizeof(glm::vec4), VK_VERTEX_INPUT_RATE_VERTEX);
		vertexBindings[1] = vkTools::initializers::vertexInputBindingDescription(1, sizeof(glm::vec4), VK_VERTEX_INPUT_RATE_VERTEX);

		std::array<VkVertexInputAttributeDescription, 2> vertexAttribs = {};
		// Position
		vertexAttribs[0] = vkTools::initializers::vertexInputAttributeDescription(0, 0, VK_FORMAT_R32G32_SFLOAT, 0);
		// UV
		vertexAttribs[1] = vkTools::initializers::vertexInputAttributeDescription(1, 1, VK_FORMAT_R32G32_SFLOAT, sizeof(glm::vec2));

		VkPipelineVertexInputStateCreateInfo inputState = vkTools::initializers::pipelineVertexInputStateCreateInfo();
		inputState.vertexBindingDescriptionCount = vertexBindings.size();
		inputState.pVertexBindingDescriptions = vertexBindings.data();
		inputState.vertexAttributeDescriptionCount = vertexAttribs.size();
		inputState.pVertexAttributeDescriptions = vertexAttribs.data();

		VkGraphicsPipelineCreateInfo pipelineCreateInfo =
			vkTools::initializers::pipelineCreateInfo(
				pipelineLayout,
				renderPass,
				0);

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

		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, 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_COLOR_ATTACHMENT_OPTIMAL;
		attachments[0].finalLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;

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

		VkSubpassDescription subpass = {};
		subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
		subpass.flags = 0;
		subpass.inputAttachmentCount = 0;
		subpass.pInputAttachments = NULL;
		subpass.colorAttachmentCount = 1;
		subpass.pColorAttachments = &colorReference;
		subpass.pResolveAttachments = NULL;
		subpass.pDepthStencilAttachment = &depthReference;
		subpass.preserveAttachmentCount = 0;
		subpass.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 = &subpass;
		renderPassInfo.dependencyCount = 0;
		renderPassInfo.pDependencies = NULL;

		VK_CHECK_RESULT(vkCreateRenderPass(device, &renderPassInfo, nullptr, &renderPass));
	}

	// Map buffer 
	void beginTextUpdate()
	{
		VK_CHECK_RESULT(vkMapMemory(device, 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)
	{
		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 - STB_FIRST_CHAR];
			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 - STB_FIRST_CHAR];

			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(device, memory);
		mapped = nullptr;
		updateCommandBuffers();
	}

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

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

		VkRenderPassBeginInfo renderPassBeginInfo = vkTools::initializers::renderPassBeginInfo();
		renderPassBeginInfo.renderPass = renderPass;
		renderPassBeginInfo.renderArea.extent.width = *frameBufferWidth;
		renderPassBeginInfo.renderArea.extent.height = *frameBufferHeight;
		renderPassBeginInfo.clearValueCount = 1;
		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 = vkTools::initializers::viewport((float)*frameBufferWidth, (float)*frameBufferHeight, 0.0f, 1.0f);
			vkCmdSetViewport(cmdBuffers[i], 0, 1, &viewport);

			VkRect2D scissor = vkTools::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]));
		}
	}

	// Submit the text command buffers to a queue
	void submit(VkQueue queue, uint32_t bufferindex, VkSubmitInfo submitInfo)
	{
		if (!visible)
		{
			return;
		}

		submitInfo.pCommandBuffers = &cmdBuffers[bufferindex];
		submitInfo.commandBufferCount = 1;

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

	void reallocateCommandBuffers()
	{
		vkFreeCommandBuffers(device, commandPool, cmdBuffers.size(), cmdBuffers.data());

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

		VK_CHECK_RESULT(vkAllocateCommandBuffers(device, &cmdBufAllocateInfo, cmdBuffers.data()));
	}

};