/*
* Vulkan Example - Using occlusion query for visibility testing
*
* 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 VERTEX_BUFFER_BIND_ID 0
#define ENABLE_VALIDATION false

class VulkanExample : public VulkanExampleBase
{
public:

	struct {
		vkglTF::Model teapot;
		vkglTF::Model plane;
		vkglTF::Model sphere;
	} models;

	struct {
		vks::Buffer occluder;
		vks::Buffer teapot;
		vks::Buffer sphere;
	} uniformBuffers;

	struct UBOVS {
		glm::mat4 projection;
		glm::mat4 view;
		glm::mat4 model;
		glm::vec4 color = glm::vec4(0.0f);
		glm::vec4 lightPos = glm::vec4(10.0f, -10.0f, 10.0f, 1.0f);
		float visible;
	} uboVS;

	struct {
		VkPipeline solid;
		VkPipeline occluder;
		// Pipeline with basic shaders used for occlusion pass
		VkPipeline simple;
	} pipelines;

	struct {
		VkDescriptorSet teapot;
		VkDescriptorSet sphere;
	} descriptorSets;

	VkPipelineLayout pipelineLayout;
	VkDescriptorSet descriptorSet;
	VkDescriptorSetLayout descriptorSetLayout;

	// Pool that stores all occlusion queries
	VkQueryPool queryPool;

	// Passed query samples
	uint64_t passedSamples[2] = { 1,1 };

	VulkanExample() : VulkanExampleBase(ENABLE_VALIDATION)
	{
		title = "Occlusion queries";
		camera.type = Camera::CameraType::lookat;
		camera.setPosition(glm::vec3(0.0f, 0.0f, -7.5f));
		camera.setRotation(glm::vec3(0.0f, -123.75f, 0.0f));
		camera.setRotationSpeed(0.5f);
		camera.setPerspective(60.0f, (float)width / (float)height, 1.0f, 256.0f);
		settings.overlay = true;
	}

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

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

		vkDestroyQueryPool(device, queryPool, nullptr);

		uniformBuffers.occluder.destroy();
		uniformBuffers.sphere.destroy();
		uniformBuffers.teapot.destroy();
	}

	// Create a query pool for storing the occlusion query result
	void setupQueryPool()
	{
		VkQueryPoolCreateInfo queryPoolInfo = {};
		queryPoolInfo.sType = VK_STRUCTURE_TYPE_QUERY_POOL_CREATE_INFO;
		queryPoolInfo.queryType = VK_QUERY_TYPE_OCCLUSION;
		queryPoolInfo.queryCount = 2;
		VK_CHECK_RESULT(vkCreateQueryPool(device, &queryPoolInfo, NULL, &queryPool));
	}

	// Retrieves the results of the occlusion queries submitted to the command buffer
	void getQueryResults()
	{
		// We use vkGetQueryResults to copy the results into a host visible buffer
		vkGetQueryPoolResults(
			device,
			queryPool,
			0,
			2,
			sizeof(passedSamples),
			passedSamples,
			sizeof(uint64_t),
			// Store results a 64 bit values and wait until the results have been finished
			// If you don't want to wait, you can use VK_QUERY_RESULT_WITH_AVAILABILITY_BIT
			// which also returns the state of the result (ready) in the result
			VK_QUERY_RESULT_64_BIT | VK_QUERY_RESULT_WAIT_BIT);
	}

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

		VkClearValue clearValues[2];
		clearValues[0].color = defaultClearColor;
		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 (int32_t i = 0; i < drawCmdBuffers.size(); ++i)
		{
			// Set target frame buffer
			renderPassBeginInfo.framebuffer = frameBuffers[i];

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

			// Reset query pool
			// Must be done outside of render pass
			vkCmdResetQueryPool(drawCmdBuffers[i], queryPool, 0, 2);

			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 };

			glm::mat4 modelMatrix = glm::mat4(1.0f);

			// Occlusion pass
			vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelines.simple);

			// Occluder first
			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSet, 0, NULL);
			models.plane.draw(drawCmdBuffers[i]);

			// Teapot
			vkCmdBeginQuery(drawCmdBuffers[i], queryPool, 0, VK_FLAGS_NONE);
			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSets.teapot, 0, NULL);
			models.teapot.draw(drawCmdBuffers[i]);
			vkCmdEndQuery(drawCmdBuffers[i], queryPool, 0);

			// Sphere
			vkCmdBeginQuery(drawCmdBuffers[i], queryPool, 1, VK_FLAGS_NONE);
			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSets.sphere, 0, NULL);
			models.sphere.draw(drawCmdBuffers[i]);
			vkCmdEndQuery(drawCmdBuffers[i], queryPool, 1);

			// Visible pass
			// Clear color and depth attachments
			VkClearAttachment clearAttachments[2] = {};

			clearAttachments[0].aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
			clearAttachments[0].clearValue.color = defaultClearColor;
			clearAttachments[0].colorAttachment = 0;

			clearAttachments[1].aspectMask = VK_IMAGE_ASPECT_DEPTH_BIT;
			clearAttachments[1].clearValue.depthStencil = { 1.0f, 0 };

			VkClearRect clearRect = {};
			clearRect.layerCount = 1;
			clearRect.rect.offset = { 0, 0 };
			clearRect.rect.extent = { width, height };

			vkCmdClearAttachments(
				drawCmdBuffers[i],
				2,
				clearAttachments,
				1,
				&clearRect);

			vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelines.solid);

			// Teapot
			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSets.teapot, 0, NULL);
			models.teapot.draw(drawCmdBuffers[i]);

			// Sphere
			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSets.sphere, 0, NULL);
			models.sphere.draw(drawCmdBuffers[i]);

			// Occluder
			vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelines.occluder);
			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSet, 0, NULL);
			models.plane.draw(drawCmdBuffers[i]);

			drawUI(drawCmdBuffers[i]);

			vkCmdEndRenderPass(drawCmdBuffers[i]);

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

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

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

		// Read query results for displaying in next frame
		getQueryResults();

		VulkanExampleBase::submitFrame();
	}

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

	void setupDescriptorPool()
	{
		std::vector<VkDescriptorPoolSize> poolSizes =
		{
			// One uniform buffer block for each mesh
			vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 3)
		};

		VkDescriptorPoolCreateInfo descriptorPoolInfo =
			vks::initializers::descriptorPoolCreateInfo(
				poolSizes.size(),
				poolSizes.data(),
				3);

		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.data(),
				setLayoutBindings.size());

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

		VkPipelineLayoutCreateInfo pPipelineLayoutCreateInfo =
			vks::initializers::pipelineLayoutCreateInfo(
				&descriptorSetLayout,
				1);

		VK_CHECK_RESULT(vkCreatePipelineLayout(device, &pPipelineLayoutCreateInfo, nullptr, &pipelineLayout));
	}

	void setupDescriptorSets()
	{
		VkDescriptorSetAllocateInfo allocInfo =
			vks::initializers::descriptorSetAllocateInfo(
				descriptorPool,
				&descriptorSetLayout,
				1);

		// Occluder (plane)
		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,
				&uniformBuffers.occluder.descriptor)
		};

		vkUpdateDescriptorSets(device, writeDescriptorSets.size(), writeDescriptorSets.data(), 0, NULL);

		// Teapot
		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &allocInfo, &descriptorSets.teapot));
		writeDescriptorSets[0].dstSet = descriptorSets.teapot;
		writeDescriptorSets[0].pBufferInfo = &uniformBuffers.teapot.descriptor;
		vkUpdateDescriptorSets(device, writeDescriptorSets.size(), writeDescriptorSets.data(), 0, NULL);

		// Sphere
		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &allocInfo, &descriptorSets.sphere));
		writeDescriptorSets[0].dstSet = descriptorSets.sphere;
		writeDescriptorSets[0].pBufferInfo = &uniformBuffers.sphere.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);
		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, 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::Color });;

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

		// Basic pipeline for coloring occluded objects
		shaderStages[0] = loadShader(getShadersPath() + "occlusionquery/simple.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
		shaderStages[1] = loadShader(getShadersPath() + "occlusionquery/simple.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
		rasterizationState.cullMode = VK_CULL_MODE_NONE;
		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCI, nullptr, &pipelines.simple));

		// Visual pipeline for the occluder
		shaderStages[0] = loadShader(getShadersPath() + "occlusionquery/occluder.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
		shaderStages[1] = loadShader(getShadersPath() + "occlusionquery/occluder.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
		// Enable blending
		blendAttachmentState.blendEnable = VK_TRUE;
		blendAttachmentState.colorBlendOp = VK_BLEND_OP_ADD;
		blendAttachmentState.srcColorBlendFactor = VK_BLEND_FACTOR_SRC_COLOR;
		blendAttachmentState.dstColorBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_SRC_COLOR;
		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCI, nullptr, &pipelines.occluder));
	}

	// 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,
			&uniformBuffers.occluder,
			sizeof(uboVS)));

		// Teapot
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&uniformBuffers.teapot,
			sizeof(uboVS)));

		// Sphere
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&uniformBuffers.sphere,
			sizeof(uboVS)));

		// Map persistent
		VK_CHECK_RESULT(uniformBuffers.occluder.map());
		VK_CHECK_RESULT(uniformBuffers.teapot.map());
		VK_CHECK_RESULT(uniformBuffers.sphere.map());

		updateUniformBuffers();
	}

	void updateUniformBuffers()
	{
		uboVS.projection = camera.matrices.perspective;
		uboVS.view = camera.matrices.view;

		uint8_t *pData;
		// Occluder
		uboVS.visible = 1.0f;
		uboVS.model = glm::scale(glm::mat4(1.0f), glm::vec3(6.0f));
		uboVS.color = glm::vec4(0.0f, 0.0f, 1.0f, 0.5f);
		memcpy(uniformBuffers.occluder.mapped, &uboVS, sizeof(uboVS));

		// Teapot
		// Toggle color depending on visibility
		uboVS.visible = (passedSamples[0] > 0) ? 1.0f : 0.0f;
		uboVS.model = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, 0.0f, -3.0f));
		uboVS.color = glm::vec4(1.0f, 0.0f, 0.0f, 1.0f);
		memcpy(uniformBuffers.teapot.mapped, &uboVS, sizeof(uboVS));

		// Sphere
		// Toggle color depending on visibility
		uboVS.visible = (passedSamples[1] > 0) ? 1.0f : 0.0f;
		uboVS.model = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, 0.0f, 3.0f));
		uboVS.color = glm::vec4(0.0f, 1.0f, 0.0f, 1.0f);
		memcpy(uniformBuffers.sphere.mapped, &uboVS, sizeof(uboVS));
	}

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

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

	virtual void OnUpdateUIOverlay(vks::UIOverlay *overlay)
	{
		if (overlay->header("Occlusion query results")) {
			overlay->text("Teapot: %d samples passed", passedSamples[0]);
			overlay->text("Sphere: %d samples passed", passedSamples[1]);
		}
	}

};

VULKAN_EXAMPLE_MAIN()