/*
* Vulkan Example - Tessellation shader PN triangles
*
* Based on http://alex.vlachos.com/graphics/CurvedPNTriangles.pdf
* Shaders based on http://onrendering.blogspot.de/2011/12/tessellation-on-gpu-curved-pn-triangles.html
*
* Copyright (C) 2016 by Sascha Willems - www.saschawillems.de
*
* This code is licensed under the MIT license (MIT) (http://opensource.org/licenses/MIT)
*/

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

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

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

#define VERTEX_BUFFER_BIND_ID 0
#define ENABLE_VALIDATION false

class VulkanExample : public VulkanExampleBase
{
public:
	bool splitScreen = true;
	bool wireframe = true;

	struct {
		vks::Texture2D colorMap;
	} textures;

	struct {
		VkPipelineVertexInputStateCreateInfo inputState;
		std::vector<VkVertexInputBindingDescription> bindingDescriptions;
		std::vector<VkVertexInputAttributeDescription> attributeDescriptions;
	} vertices;

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

	struct {
		vks::Model object;
	} models;

	struct {
		vks::Buffer tessControl, tessEval;
	} uniformBuffers;
	
	struct UBOTessControl {
		float tessLevel = 3.0f;
	} uboTessControl;

	struct UBOTessEval {
		glm::mat4 projection;
		glm::mat4 model;
		float tessAlpha = 1.0f;
	} uboTessEval;

	struct Pipelines {
		VkPipeline solid;
		VkPipeline wire = VK_NULL_HANDLE;
		VkPipeline solidPassThrough;
		VkPipeline wirePassThrough = VK_NULL_HANDLE;
	} pipelines;
	
	VkPipelineLayout pipelineLayout;
	VkDescriptorSet descriptorSet;
	VkDescriptorSetLayout descriptorSetLayout;

	VulkanExample() : VulkanExampleBase(ENABLE_VALIDATION)
	{
		zoom = -6.5f;
		rotation = glm::vec3(-350.0f, 60.0f, 0.0f);
		cameraPos = glm::vec3(-3.0f, 2.3f, 0.0f);
		title = "Tessellation shader (PN Triangles)";
		settings.overlay = true;
	}

	~VulkanExample()
	{
		// Clean up used Vulkan resources 
		// Note : Inherited destructor cleans up resources stored in base class
		vkDestroyPipeline(device, pipelines.solid, nullptr);
		if (pipelines.wire != VK_NULL_HANDLE) {
			vkDestroyPipeline(device, pipelines.wire, nullptr);
		};
		vkDestroyPipeline(device, pipelines.solidPassThrough, nullptr);
		if (pipelines.wirePassThrough != VK_NULL_HANDLE) {
			vkDestroyPipeline(device, pipelines.wirePassThrough, nullptr);
		};

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

		models.object.destroy();
		uniformBuffers.tessControl.destroy();
		uniformBuffers.tessEval.destroy();
		textures.colorMap.destroy();
	}

	// Enable physical device features required for this example				
	virtual void getEnabledFeatures()
	{
		// Example uses tessellation shaders
		if (deviceFeatures.tessellationShader) {
			enabledFeatures.tessellationShader = VK_TRUE;
		}
		else {
			vks::tools::exitFatal("Selected GPU does not support tessellation shaders!", VK_ERROR_FEATURE_NOT_PRESENT);
		}
		// Fill mode non solid is required for wireframe display
		if (deviceFeatures.fillModeNonSolid) {
			enabledFeatures.fillModeNonSolid = VK_TRUE;
		}
		else {
			wireframe = false;
		}
	}

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

		VkClearValue clearValues[2];
		clearValues[0].color = { {0.5f, 0.5f, 0.5f, 0.0f} };
		clearValues[1].depthStencil = { 1.0f, 0 };

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

		for (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(splitScreen ? (float)width / 2.0f : (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);

			vkCmdSetLineWidth(drawCmdBuffers[i], 1.0f);

			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSet, 0, NULL);

			VkDeviceSize offsets[1] = { 0 };
			vkCmdBindVertexBuffers(drawCmdBuffers[i], VERTEX_BUFFER_BIND_ID, 1, &models.object.vertices.buffer, offsets);
			vkCmdBindIndexBuffer(drawCmdBuffers[i], models.object.indices.buffer, 0, VK_INDEX_TYPE_UINT32);

			if (splitScreen) {
				vkCmdSetViewport(drawCmdBuffers[i], 0, 1, &viewport);
				vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, wireframe ? pipelines.wirePassThrough : pipelines.solidPassThrough);
				vkCmdDrawIndexed(drawCmdBuffers[i], models.object.indexCount, 1, 0, 0, 0);
				viewport.x = float(width) / 2;
			}

			vkCmdSetViewport(drawCmdBuffers[i], 0, 1, &viewport);
			vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, wireframe ? pipelines.wire : pipelines.solid);
			vkCmdDrawIndexed(drawCmdBuffers[i], models.object.indexCount, 1, 0, 0, 0);

			drawUI(drawCmdBuffers[i]);

			vkCmdEndRenderPass(drawCmdBuffers[i]);

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

	void loadAssets()
	{
		models.object.loadFromFile(getAssetPath() + "models/lowpoly/deer.dae", vertexLayout, 1.0f, vulkanDevice, queue);
		if (deviceFeatures.textureCompressionBC) {
			textures.colorMap.loadFromFile(getAssetPath() + "textures/deer_bc3_unorm.ktx", VK_FORMAT_BC3_UNORM_BLOCK, vulkanDevice, queue);
		}
		else if (deviceFeatures.textureCompressionASTC_LDR) {
			textures.colorMap.loadFromFile(getAssetPath() + "textures/deer_astc_8x8_unorm.ktx", VK_FORMAT_ASTC_8x8_UNORM_BLOCK, vulkanDevice, queue);
		}
		else if (deviceFeatures.textureCompressionETC2) {
			textures.colorMap.loadFromFile(getAssetPath() + "textures/deer_etc2_unorm.ktx", VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK, vulkanDevice, queue);
		}
		else {
			vks::tools::exitFatal("Device does not support any compressed texture format!", VK_ERROR_FEATURE_NOT_PRESENT);
		}
	}

	void setupVertexDescriptions()
	{
		// Binding description
		vertices.bindingDescriptions.resize(1);
		vertices.bindingDescriptions[0] =
			vks::initializers::vertexInputBindingDescription(
				VERTEX_BUFFER_BIND_ID,
				vertexLayout.stride(),
				VK_VERTEX_INPUT_RATE_VERTEX);

		// Attribute descriptions
		// Describes memory layout and shader positions
		vertices.attributeDescriptions.resize(3);

		// Location 0 : Position
		vertices.attributeDescriptions[0] =
			vks::initializers::vertexInputAttributeDescription(
				VERTEX_BUFFER_BIND_ID,
				0,
				VK_FORMAT_R32G32B32_SFLOAT,
				0);

		// Location 1 : Normals
		vertices.attributeDescriptions[1] =
			vks::initializers::vertexInputAttributeDescription(
				VERTEX_BUFFER_BIND_ID,
				1,
				VK_FORMAT_R32G32B32_SFLOAT,
				sizeof(float) * 3);

		// Location 2 : Texture coordinates
		vertices.attributeDescriptions[2] =
			vks::initializers::vertexInputAttributeDescription(
				VERTEX_BUFFER_BIND_ID,
				2,
				VK_FORMAT_R32G32_SFLOAT,
				sizeof(float) * 6);

		vertices.inputState = vks::initializers::pipelineVertexInputStateCreateInfo();
		vertices.inputState.vertexBindingDescriptionCount = vertices.bindingDescriptions.size();
		vertices.inputState.pVertexBindingDescriptions = vertices.bindingDescriptions.data();
		vertices.inputState.vertexAttributeDescriptionCount = vertices.attributeDescriptions.size();
		vertices.inputState.pVertexAttributeDescriptions = vertices.attributeDescriptions.data();
	}

	void setupDescriptorPool()
	{
		// Example uses two ubos and one combined image sampler
		std::vector<VkDescriptorPoolSize> poolSizes =
		{
			vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 2),
			vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1),
		};

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

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

	void setupDescriptorSetLayout()
	{
		std::vector<VkDescriptorSetLayoutBinding> setLayoutBindings =
		{
			// Binding 0 : Tessellation control shader ubo
			vks::initializers::descriptorSetLayoutBinding(
				VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
				VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT,
				0),
			// Binding 1 : Tessellation evaluation shader ubo
			vks::initializers::descriptorSetLayoutBinding(
				VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
				VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT,
				1),
			// Binding 2 : Fragment shader combined sampler
			vks::initializers::descriptorSetLayoutBinding(
				VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,
				VK_SHADER_STAGE_FRAGMENT_BIT,
				2),
		};

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

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

		VkDescriptorImageInfo texDescriptor =
			vks::initializers::descriptorImageInfo(
				textures.colorMap.sampler,
				textures.colorMap.view,
				VK_IMAGE_LAYOUT_GENERAL);

		std::vector<VkWriteDescriptorSet> writeDescriptorSets =
		{
			// Binding 0 : Tessellation control shader ubo
			vks::initializers::writeDescriptorSet(
			descriptorSet,
				VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
				0,
				&uniformBuffers.tessControl.descriptor),
			// Binding 1 : Tessellation evaluation shader ubo
			vks::initializers::writeDescriptorSet(
				descriptorSet,
				VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,
				1,
				&uniformBuffers.tessEval.descriptor),
			// Binding 2 : Color map 
			vks::initializers::writeDescriptorSet(
				descriptorSet,
				VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,
				2,
				&texDescriptor)
		};

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

	void preparePipelines()
	{
		VkPipelineInputAssemblyStateCreateInfo inputAssemblyState =
			vks::initializers::pipelineInputAssemblyStateCreateInfo(
				VK_PRIMITIVE_TOPOLOGY_PATCH_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,
			VK_DYNAMIC_STATE_LINE_WIDTH
		};
		VkPipelineDynamicStateCreateInfo dynamicState =
			vks::initializers::pipelineDynamicStateCreateInfo(
				dynamicStateEnables.data(),
				dynamicStateEnables.size(),
				0);

		VkPipelineTessellationStateCreateInfo tessellationState =
			vks::initializers::pipelineTessellationStateCreateInfo(3);

		// Tessellation pipelines
		// Load shaders
		std::array<VkPipelineShaderStageCreateInfo, 4> shaderStages;

		shaderStages[0] = loadShader(getAssetPath() + "shaders/tessellation/base.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
		shaderStages[1] = loadShader(getAssetPath() + "shaders/tessellation/base.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
		shaderStages[2] = loadShader(getAssetPath() + "shaders/tessellation/pntriangles.tesc.spv", VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT);
		shaderStages[3] = loadShader(getAssetPath() + "shaders/tessellation/pntriangles.tese.spv", VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT);

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

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

		// Tessellation pipelines
		// Solid
		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCreateInfo, nullptr, &pipelines.solid));
		// Wireframe
		if (deviceFeatures.fillModeNonSolid) {
			rasterizationState.polygonMode = VK_POLYGON_MODE_LINE;
			VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCreateInfo, nullptr, &pipelines.wire));
		}

		// Pass through pipelines
		// Load pass through tessellation shaders (Vert and frag are reused)
		shaderStages[2] = loadShader(getAssetPath() + "shaders/tessellation/passthrough.tesc.spv", VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT);
		shaderStages[3] = loadShader(getAssetPath() + "shaders/tessellation/passthrough.tese.spv", VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT);

		// Solid
		rasterizationState.polygonMode = VK_POLYGON_MODE_FILL;
		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCreateInfo, nullptr, &pipelines.solidPassThrough));
		// Wireframe
		if (deviceFeatures.fillModeNonSolid) {
			rasterizationState.polygonMode = VK_POLYGON_MODE_LINE;
			VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCreateInfo, nullptr, &pipelines.wirePassThrough));
		}
	}

	// Prepare and initialize uniform buffer containing shader uniforms
	void prepareUniformBuffers()
	{
		// Tessellation evaluation shader uniform buffer
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&uniformBuffers.tessEval,
			sizeof(uboTessEval)));

		// Tessellation control shader uniform buffer
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&uniformBuffers.tessControl,
			sizeof(uboTessControl)));

		// Map persistent
		VK_CHECK_RESULT(uniformBuffers.tessControl.map());
		VK_CHECK_RESULT(uniformBuffers.tessEval.map());

		updateUniformBuffers();
	}

	void updateUniformBuffers()
	{
		// Tessellation eval
		glm::mat4 viewMatrix = glm::mat4(1.0f);
		uboTessEval.projection = glm::perspective(glm::radians(45.0f), (float)(width* ((splitScreen) ? 0.5f : 1.0f)) / (float)height, 0.1f, 256.0f);
		viewMatrix = glm::translate(viewMatrix, glm::vec3(0.0f, 0.0f, zoom));

		uboTessEval.model = glm::mat4(1.0f);
		uboTessEval.model = viewMatrix * glm::translate(uboTessEval.model, cameraPos);
		uboTessEval.model = glm::rotate(uboTessEval.model, glm::radians(rotation.x), glm::vec3(1.0f, 0.0f, 0.0f));
		uboTessEval.model = glm::rotate(uboTessEval.model, glm::radians(rotation.y), glm::vec3(0.0f, 1.0f, 0.0f));
		uboTessEval.model = glm::rotate(uboTessEval.model, glm::radians(rotation.z), glm::vec3(0.0f, 0.0f, 1.0f));

		// Tessellation evaulation uniform block
		memcpy(uniformBuffers.tessEval.mapped, &uboTessEval, sizeof(uboTessEval));

		// Tessellation control uniform block
		memcpy(uniformBuffers.tessControl.mapped, &uboTessControl, sizeof(uboTessControl));
	}

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

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

		VulkanExampleBase::submitFrame();
	}

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

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

	virtual void viewChanged()
	{
		updateUniformBuffers();
	}

	virtual void OnUpdateUIOverlay(vks::UIOverlay *overlay)
	{
		if (overlay->header("Settings")) {
			if (overlay->inputFloat("Tessellation level", &uboTessControl.tessLevel, 0.25f, 2)) {
				updateUniformBuffers();
			}
			if (deviceFeatures.fillModeNonSolid) {
				if (overlay->checkBox("Wireframe", &wireframe)) {
					updateUniformBuffers();
					buildCommandBuffers();
				}
				if (overlay->checkBox("Splitscreen", &splitScreen)) {
					updateUniformBuffers();
					buildCommandBuffers();
				}
			}
		}
	}
};

VULKAN_EXAMPLE_MAIN()