multisampling.cpp

/*
* Vulkan Example - Multisampling using resolve attachments
*
* Copyright (C) 2016 by Sascha Willems - www.saschawillems.de
*
* This code is licensed under the MIT license (MIT) (http://opensource.org/licenses/MIT)
*/

#include "vulkanexamplebase.h"
#include "VulkanglTFModel.h"

#define ENABLE_VALIDATION false

struct {
	struct {
		VkImage image;
		VkImageView view;
		VkDeviceMemory memory;
	} color;
	struct {
		VkImage image;
		VkImageView view;
		VkDeviceMemory memory;
	} depth;
} multisampleTarget;

class VulkanExample : public VulkanExampleBase
{
public:
	bool useSampleShading = false;
	VkSampleCountFlagBits sampleCount = VK_SAMPLE_COUNT_1_BIT;

	vkglTF::Model model;

	vks::Buffer uniformBuffer;

	struct UBOVS {
		glm::mat4 projection;
		glm::mat4 model;
		glm::vec4 lightPos = glm::vec4(5.0f, -5.0f, 5.0f, 1.0f);
	} uboVS;

	struct {
		VkPipeline MSAA;
		VkPipeline MSAASampleShading;
	} pipelines;

	VkPipelineLayout pipelineLayout;
	VkDescriptorSet descriptorSet;
	VkDescriptorSetLayout descriptorSetLayout;

	VulkanExample() : VulkanExampleBase(ENABLE_VALIDATION)
	{
		title = "Multisampling";
		camera.type = Camera::CameraType::lookat;
		camera.setPerspective(60.0f, (float)width / (float)height, 0.1f, 256.0f);
		camera.setRotation(glm::vec3(0.0f, -90.0f, 0.0f));
		camera.setTranslation(glm::vec3(2.5f, 2.5f, -7.5f));
	}

	~VulkanExample()
	{
		// Clean up used Vulkan resources
		// Note : Inherited destructor cleans up resources stored in base class
		vkDestroyPipeline(device, pipelines.MSAA, nullptr);
		vkDestroyPipeline(device, pipelines.MSAASampleShading, nullptr);

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

		// Destroy MSAA target
		vkDestroyImage(device, multisampleTarget.color.image, nullptr);
		vkDestroyImageView(device, multisampleTarget.color.view, nullptr);
		vkFreeMemory(device, multisampleTarget.color.memory, nullptr);
		vkDestroyImage(device, multisampleTarget.depth.image, nullptr);
		vkDestroyImageView(device, multisampleTarget.depth.view, nullptr);
		vkFreeMemory(device, multisampleTarget.depth.memory, nullptr);

		uniformBuffer.destroy();
	}

	// Enable physical device features required for this example
	virtual void getEnabledFeatures()
	{
		// Enable sample rate shading filtering if supported
		if (deviceFeatures.sampleRateShading) {
			enabledFeatures.sampleRateShading = VK_TRUE;
		}
		// Enable anisotropic filtering if supported
		if (deviceFeatures.samplerAnisotropy) {
			enabledFeatures.samplerAnisotropy = VK_TRUE;
		}
	}

	// Creates a multi sample render target (image and view) that is used to resolve
	// into the visible frame buffer target in the render pass
	void setupMultisampleTarget()
	{
		// Check if device supports requested sample count for color and depth frame buffer
		assert((deviceProperties.limits.framebufferColorSampleCounts >= sampleCount) && (deviceProperties.limits.framebufferDepthSampleCounts >= sampleCount));

		// Color target
		VkImageCreateInfo info = vks::initializers::imageCreateInfo();
		info.imageType = VK_IMAGE_TYPE_2D;
		info.format = swapChain.colorFormat;
		info.extent.width = width;
		info.extent.height = height;
		info.extent.depth = 1;
		info.mipLevels = 1;
		info.arrayLayers = 1;
		info.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
		info.tiling = VK_IMAGE_TILING_OPTIMAL;
		info.samples = sampleCount;
		// Image will only be used as a transient target
		info.usage = VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT | VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
		info.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;

		VK_CHECK_RESULT(vkCreateImage(device, &info, nullptr, &multisampleTarget.color.image));

		VkMemoryRequirements memReqs;
		vkGetImageMemoryRequirements(device, multisampleTarget.color.image, &memReqs);
		VkMemoryAllocateInfo memAlloc = vks::initializers::memoryAllocateInfo();
		memAlloc.allocationSize = memReqs.size;
		// We prefer a lazily allocated memory type
		// This means that the memory gets allocated when the implementation sees fit, e.g. when first using the images
		VkBool32 lazyMemTypePresent;
		memAlloc.memoryTypeIndex = vulkanDevice->getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT, &lazyMemTypePresent);
		if (!lazyMemTypePresent)
		{
			// If this is not available, fall back to device local memory
			memAlloc.memoryTypeIndex = vulkanDevice->getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
		}
		VK_CHECK_RESULT(vkAllocateMemory(device, &memAlloc, nullptr, &multisampleTarget.color.memory));
		vkBindImageMemory(device, multisampleTarget.color.image, multisampleTarget.color.memory, 0);

		// Create image view for the MSAA target
		VkImageViewCreateInfo viewInfo = vks::initializers::imageViewCreateInfo();
		viewInfo.image = multisampleTarget.color.image;
		viewInfo.viewType = VK_IMAGE_VIEW_TYPE_2D;
		viewInfo.format = swapChain.colorFormat;
		viewInfo.components.r = VK_COMPONENT_SWIZZLE_R;
		viewInfo.components.g = VK_COMPONENT_SWIZZLE_G;
		viewInfo.components.b = VK_COMPONENT_SWIZZLE_B;
		viewInfo.components.a = VK_COMPONENT_SWIZZLE_A;
		viewInfo.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
		viewInfo.subresourceRange.levelCount = 1;
		viewInfo.subresourceRange.layerCount = 1;

		VK_CHECK_RESULT(vkCreateImageView(device, &viewInfo, nullptr, &multisampleTarget.color.view));

		// Depth target
		info.imageType = VK_IMAGE_TYPE_2D;
		info.format = depthFormat;
		info.extent.width = width;
		info.extent.height = height;
		info.extent.depth = 1;
		info.mipLevels = 1;
		info.arrayLayers = 1;
		info.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
		info.tiling = VK_IMAGE_TILING_OPTIMAL;
		info.samples = sampleCount;
		// Image will only be used as a transient target
		info.usage = VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT | VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT;
		info.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;

		VK_CHECK_RESULT(vkCreateImage(device, &info, nullptr, &multisampleTarget.depth.image));

		vkGetImageMemoryRequirements(device, multisampleTarget.depth.image, &memReqs);
		memAlloc = vks::initializers::memoryAllocateInfo();
		memAlloc.allocationSize = memReqs.size;

		memAlloc.memoryTypeIndex = vulkanDevice->getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT, &lazyMemTypePresent);
		if (!lazyMemTypePresent)
		{
			memAlloc.memoryTypeIndex = vulkanDevice->getMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
		}

		VK_CHECK_RESULT(vkAllocateMemory(device, &memAlloc, nullptr, &multisampleTarget.depth.memory));
		vkBindImageMemory(device, multisampleTarget.depth.image, multisampleTarget.depth.memory, 0);

		// Create image view for the MSAA target
		viewInfo.image = multisampleTarget.depth.image;
		viewInfo.viewType = VK_IMAGE_VIEW_TYPE_2D;
		viewInfo.format = depthFormat;
		viewInfo.components.r = VK_COMPONENT_SWIZZLE_R;
		viewInfo.components.g = VK_COMPONENT_SWIZZLE_G;
		viewInfo.components.b = VK_COMPONENT_SWIZZLE_B;
		viewInfo.components.a = VK_COMPONENT_SWIZZLE_A;
		viewInfo.subresourceRange.aspectMask = VK_IMAGE_ASPECT_DEPTH_BIT | VK_IMAGE_ASPECT_STENCIL_BIT;
		viewInfo.subresourceRange.levelCount = 1;
		viewInfo.subresourceRange.layerCount = 1;

		VK_CHECK_RESULT(vkCreateImageView(device, &viewInfo, nullptr, &multisampleTarget.depth.view));
	}

	// Setup a render pass for using a multi sampled attachment
	// and a resolve attachment that the msaa image is resolved
	// to at the end of the render pass
	void setupRenderPass()
	{
		// Overrides the virtual function of the base class

		std::array<VkAttachmentDescription, 3> attachments = {};

		// Multisampled attachment that we render to
		attachments[0].format = swapChain.colorFormat;
		attachments[0].samples = sampleCount;
		attachments[0].loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
		attachments[0].storeOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
		attachments[0].stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
		attachments[0].stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
		attachments[0].initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
		attachments[0].finalLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;

		// This is the frame buffer attachment to where the multisampled image
		// will be resolved to and which will be presented to the swapchain
		attachments[1].format = swapChain.colorFormat;
		attachments[1].samples = VK_SAMPLE_COUNT_1_BIT;
		attachments[1].loadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
		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_PRESENT_SRC_KHR;

		// Multisampled depth attachment we render to
		attachments[2].format = depthFormat;
		attachments[2].samples = sampleCount;
		attachments[2].loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
		attachments[2].storeOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
		attachments[2].stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
		attachments[2].stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
		attachments[2].initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
		attachments[2].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 = 2;
		depthReference.layout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;

		// Resolve attachment reference for the color attachment
		VkAttachmentReference resolveReference = {};
		resolveReference.attachment = 1;
		resolveReference.layout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;

		VkSubpassDescription subpass = {};
		subpass.pipelineBindPoint = VK_PIPELINE_BIND_POINT_GRAPHICS;
		subpass.colorAttachmentCount = 1;
		subpass.pColorAttachments = &colorReference;
		// Pass our resolve attachments to the sub pass
		subpass.pResolveAttachments = &resolveReference;
		subpass.pDepthStencilAttachment = &depthReference;

		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;

		VkRenderPassCreateInfo renderPassInfo = vks::initializers::renderPassCreateInfo();
		renderPassInfo.attachmentCount = attachments.size();
		renderPassInfo.pAttachments = attachments.data();
		renderPassInfo.subpassCount = 1;
		renderPassInfo.pSubpasses = &subpass;
		renderPassInfo.dependencyCount = 2;
		renderPassInfo.pDependencies = dependencies.data();

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

	// Frame buffer attachments must match with render pass setup,
	// so we need to adjust frame buffer creation to cover our
	// multisample target
	void setupFrameBuffer()
	{
		// Overrides the virtual function of the base class

		std::array<VkImageView, 3> attachments;

		setupMultisampleTarget();

		attachments[0] = multisampleTarget.color.view;
		// attachment[1] = swapchain image
		attachments[2] = multisampleTarget.depth.view;

		VkFramebufferCreateInfo frameBufferCreateInfo = {};
		frameBufferCreateInfo.sType = VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO;
		frameBufferCreateInfo.pNext = NULL;
		frameBufferCreateInfo.renderPass = renderPass;
		frameBufferCreateInfo.attachmentCount = attachments.size();
		frameBufferCreateInfo.pAttachments = attachments.data();
		frameBufferCreateInfo.width = width;
		frameBufferCreateInfo.height = height;
		frameBufferCreateInfo.layers = 1;

		// Create frame buffers for every swap chain image
		frameBuffers.resize(swapChain.imageCount);
		for (uint32_t i = 0; i < frameBuffers.size(); i++)
		{
			attachments[1] = swapChain.buffers[i].view;
			VK_CHECK_RESULT(vkCreateFramebuffer(device, &frameBufferCreateInfo, nullptr, &frameBuffers[i]));
		}
	}

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

		VkClearValue clearValues[3];
		// Clear to a white background for higher contrast
		clearValues[0].color = { { 1.0f, 1.0f, 1.0f, 1.0f } };
		clearValues[1].color = { { 1.0f, 1.0f, 1.0f, 1.0f } };
		clearValues[2].depthStencil = { 1.0f, 0 };

		VkRenderPassBeginInfo renderPassBeginInfo = vks::initializers::renderPassBeginInfo();
		renderPassBeginInfo.renderPass = renderPass;
		renderPassBeginInfo.renderArea.extent.width = width;
		renderPassBeginInfo.renderArea.extent.height = height;
		renderPassBeginInfo.clearValueCount = 3;
		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);

			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSet, 0, NULL);
			vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, useSampleShading ? pipelines.MSAASampleShading : pipelines.MSAA);
			model.draw(drawCmdBuffers[i], vkglTF::RenderFlags::BindImages, pipelineLayout);

			drawUI(drawCmdBuffers[i]);

			vkCmdEndRenderPass(drawCmdBuffers[i]);

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

	void loadAssets()
	{
		model.loadFromFile(getAssetPath() + "models/voyager.gltf", vulkanDevice, queue, vkglTF::FileLoadingFlags::PreTransformVertices | vkglTF::FileLoadingFlags::FlipY);
	}

	void setupDescriptorPool()
	{
		// Example uses one ubo and one combined image sampler
		std::vector<VkDescriptorPoolSize> poolSizes =
		{
			vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 1),
			vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1),
		};

		VkDescriptorPoolCreateInfo descriptorPoolInfo =
			vks::initializers::descriptorPoolCreateInfo(
				poolSizes.size(),
				poolSizes.data(),
				2);

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

	void setupDescriptorSetLayout()
	{
		const 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));

		// Layout uses set 0 for passing vertex shader ubo and set 1 for fragment shader images (taken from glTF model)
		const std::vector<VkDescriptorSetLayout> setLayouts = {
			descriptorSetLayout,
			vkglTF::descriptorSetLayoutImage,
		};
		VkPipelineLayoutCreateInfo pPipelineLayoutCreateInfo = vks::initializers::pipelineLayoutCreateInfo(setLayouts.data(), 2);
		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, 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);
		std::vector<VkDynamicState> dynamicStateEnables = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };
		VkPipelineDynamicStateCreateInfo dynamicState = vks::initializers::pipelineDynamicStateCreateInfo(dynamicStateEnables);
		std::array<VkPipelineShaderStageCreateInfo, 2> shaderStages;

		// Setup multi sampling
		VkPipelineMultisampleStateCreateInfo multisampleState{};
		multisampleState.sType = VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO;
		// Number of samples to use for rasterization
		multisampleState.rasterizationSamples = sampleCount;

		VkGraphicsPipelineCreateInfo pipelineCI = vks::initializers::pipelineCreateInfo(pipelineLayout, renderPass, 0);
		pipelineCI.pInputAssemblyState = &inputAssemblyState;
		pipelineCI.pRasterizationState = &rasterizationState;
		pipelineCI.pColorBlendState = &colorBlendState;
		pipelineCI.pMultisampleState = &multisampleState;
		pipelineCI.pViewportState = &viewportState;
		pipelineCI.pDepthStencilState = &depthStencilState;
		pipelineCI.pDynamicState = &dynamicState;
		pipelineCI.stageCount = shaderStages.size();
		pipelineCI.pStages = shaderStages.data();
		pipelineCI.pVertexInputState = vkglTF::Vertex::getPipelineVertexInputState({ vkglTF::VertexComponent::Position, vkglTF::VertexComponent::Normal, vkglTF::VertexComponent::UV, vkglTF::VertexComponent::Color });

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

		if (vulkanDevice->features.sampleRateShading)
		{
			// MSAA with sample shading pipeline
			// Sample shading enables per-sample shading to avoid shader aliasing and smooth out e.g. high frequency texture maps
			// Note: This will trade performance for are more stable image
			
			// Enable per-sample shading (instead of per-fragment)
			multisampleState.sampleShadingEnable = VK_TRUE;
			// Minimum fraction for sample shading
			multisampleState.minSampleShading = 0.25f;
			VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCI, nullptr, &pipelines.MSAASampleShading));
		}
	}

	// 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.model = camera.matrices.view;
		memcpy(uniformBuffer.mapped, &uboVS, sizeof(uboVS));
	}

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

		// Command buffer to be sumitted to the queue
		submitInfo.commandBufferCount = 1;
		submitInfo.pCommandBuffers = &drawCmdBuffers[currentBuffer];

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

		VulkanExampleBase::submitFrame();
	}

	void prepare()
	{
		sampleCount = getMaxUsableSampleCount();
		UIOverlay.rasterizationSamples = sampleCount;
		VulkanExampleBase::prepare();
		loadAssets();
		prepareUniformBuffers();
		setupDescriptorSetLayout();
		preparePipelines();
		setupDescriptorPool();
		setupDescriptorSet();
		buildCommandBuffers();
		prepared = true;
	}

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

	// Returns the maximum sample count usable by the platform
	VkSampleCountFlagBits getMaxUsableSampleCount()
	{
		VkSampleCountFlags counts = std::min(deviceProperties.limits.framebufferColorSampleCounts, deviceProperties.limits.framebufferDepthSampleCounts);
		if (counts & VK_SAMPLE_COUNT_64_BIT) { return VK_SAMPLE_COUNT_64_BIT; }
		if (counts & VK_SAMPLE_COUNT_32_BIT) { return VK_SAMPLE_COUNT_32_BIT; }
		if (counts & VK_SAMPLE_COUNT_16_BIT) { return VK_SAMPLE_COUNT_16_BIT; }
		if (counts & VK_SAMPLE_COUNT_8_BIT) { return VK_SAMPLE_COUNT_8_BIT; }
		if (counts & VK_SAMPLE_COUNT_4_BIT) { return VK_SAMPLE_COUNT_4_BIT; }
		if (counts & VK_SAMPLE_COUNT_2_BIT) { return VK_SAMPLE_COUNT_2_BIT; }
		return VK_SAMPLE_COUNT_1_BIT;
	}

	virtual void OnUpdateUIOverlay(vks::UIOverlay *overlay)
	{
		if (vulkanDevice->features.sampleRateShading) {
			if (overlay->header("Settings")) {
				if (overlay->checkBox("Sample rate shading", &useSampleShading)) {
					buildCommandBuffers();
				}
			}
		}
	}
};

VULKAN_EXAMPLE_MAIN()