/*
* Vulkan Example - Conditional rendering
*
* Note: Requires a device that supports the VK_EXT_conditional_rendering extension
*
* With conditional rendering it's possible to execute certain rendering commands based
* on a buffer value instead of having to rebuild the command buffers.
*
* Copyright (C) 2018 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 "VulkanModel.hpp"

#define ENABLE_VALIDATION false
#define MODEL_ROWS 3

class VulkanExample : public VulkanExampleBase
{
public:
	PFN_vkCmdBeginConditionalRenderingEXT vkCmdBeginConditionalRenderingEXT;
	PFN_vkCmdEndConditionalRenderingEXT vkCmdEndConditionalRenderingEXT;
	VkPhysicalDeviceConditionalRenderingFeaturesEXT conditionalRenderingFeatures{};

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

	vks::Model model;

	struct {
		glm::mat4 projection;
		glm::mat4 modelview;
	} uboVS;

	vks::Buffer uniformBuffer;

	std::array<int32_t, MODEL_ROWS> conditionalVisibility{};
	vks::Buffer conditionalBuffer;

	VkPipelineLayout pipelineLayout;
	VkPipeline pipeline;
	VkDescriptorSetLayout descriptorSetLayout;
	VkDescriptorSet descriptorSet;

	VulkanExample() : VulkanExampleBase(ENABLE_VALIDATION)
	{
		title = "Conditional rendering";
		settings.overlay = true;
		camera.type = Camera::CameraType::lookat;
		camera.setPerspective(60.0f, (float)width / (float)height, 0.1f, 512.0f);
		camera.setRotation(glm::vec3(0.0f, 0.0f, 0.0f));
		camera.setTranslation(glm::vec3(0.0f, 0.0f, -15.0f));
		rotationSpeed *= 0.25f;

		// Enable extension required for conditional rendering
		enabledDeviceExtensions.push_back(VK_EXT_CONDITIONAL_RENDERING_EXTENSION_NAME);
		// Enable extension required to get conditional rendering supported features
		enabledInstanceExtensions.push_back(VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_EXTENSION_NAME);
	}

	~VulkanExample()
	{
		// Clean up used Vulkan resources 
		// Note : Inherited destructor cleans up resources stored in base class
		vkDestroyPipeline(device, pipeline, nullptr);
		vkDestroyPipelineLayout(device, pipelineLayout, nullptr);
		vkDestroyDescriptorSetLayout(device, descriptorSetLayout, nullptr);
		model.destroy();
		uniformBuffer.destroy();
		conditionalBuffer.destroy();
	}

	// Enable physical device features required for this example				
	virtual void getEnabledFeatures()
	{
		// Geometry shader support is required for this example
		if (deviceFeatures.geometryShader) {
			enabledFeatures.geometryShader = VK_TRUE;
		}
		else {
			vks::tools::exitFatal("Selected GPU does not support geometry shaders!", VK_ERROR_FEATURE_NOT_PRESENT);
		}
	}

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

		VkClearValue clearValues[2];
		clearValues[0].color = { { 0.0f, 0.0f, 0.0f, 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((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);

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

			struct PushBlock {
				glm::vec4 offset;
				glm::vec4 color;
			} pushBlock;

			const std::array<glm::vec3, 3> colors = {
				glm::vec3(1.0f, 0.0f, 0.0f),
				glm::vec3(0.0f, 1.0f, 0.0f),
				glm::vec3(0.0f, 0.0f, 1.0f),
			};

			/*
				[POI] Setup the conditional rendering structure that decides on wether the commands are rendered or discarded
			*/
			VkConditionalRenderingBeginInfoEXT conditionalRenderingBeginInfo{};
			conditionalRenderingBeginInfo.sType = VK_STRUCTURE_TYPE_CONDITIONAL_RENDERING_BEGIN_INFO_EXT;
			// If the value in this buffer at the given offset is zero, commands are discadrd
			conditionalRenderingBeginInfo.buffer = conditionalBuffer.buffer;
			// Offset will be changed in the loop below to toggle visibility of whole rows
			conditionalRenderingBeginInfo.offset = 0;

			vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline);
			for (int32_t x = -1; x < MODEL_ROWS - 1; x++) {
				for (int32_t y = -2; y < 3; y++) {
					pushBlock.offset = glm::vec4((float)x * 3.0f, (float)y * 2.5f, 0.0f, 1.0f);
					pushBlock.color = glm::vec4(colors[x+1], 1.0f);

					/*
						[POI] Start the conditionally rendered part (for this row)
					*/

					conditionalRenderingBeginInfo.offset = sizeof(uint32_t) * (x + 1);
					vkCmdBeginConditionalRenderingEXT(drawCmdBuffers[i], &conditionalRenderingBeginInfo);

					vkCmdPushConstants(drawCmdBuffers[i], pipelineLayout, VK_SHADER_STAGE_VERTEX_BIT, 0, sizeof(pushBlock), &pushBlock);
					vkCmdDrawIndexed(drawCmdBuffers[i], model.indexCount, 1, 0, 0, 0);

					vkCmdEndConditionalRenderingEXT(drawCmdBuffers[i]);
				}
			}

			vkCmdEndRenderPass(drawCmdBuffers[i]);

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

	void loadAssets()
	{
		model.loadFromFile(getAssetPath() + "models/suzanne.obj", vertexLayout, 0.1f, vulkanDevice, queue);
	}

	void setupDescriptorSets()
	{
		std::vector<VkDescriptorPoolSize> poolSizes = {
			vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 1),
		};
		VkDescriptorPoolCreateInfo descriptorPoolCI = vks::initializers::descriptorPoolCreateInfo(poolSizes.size(), poolSizes.data(), 1);
		VK_CHECK_RESULT(vkCreateDescriptorPool(device, &descriptorPoolCI, nullptr, &descriptorPool));

		std::vector<VkDescriptorSetLayoutBinding> setLayoutBindings = {
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, VK_SHADER_STAGE_VERTEX_BIT, 0),
		};
		VkDescriptorSetLayoutCreateInfo descriptorLayoutCI{};
		descriptorLayoutCI.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO;
		descriptorLayoutCI.bindingCount = static_cast<uint32_t>(setLayoutBindings.size());
		descriptorLayoutCI.pBindings = setLayoutBindings.data();
		VK_CHECK_RESULT(vkCreateDescriptorSetLayout(device, &descriptorLayoutCI, nullptr, &descriptorSetLayout));

		VkPipelineLayoutCreateInfo pipelineLayoutCI = vks::initializers::pipelineLayoutCreateInfo(&descriptorSetLayout, 1);
		VkPushConstantRange pushConstantRange = vks::initializers::pushConstantRange(VK_SHADER_STAGE_VERTEX_BIT, sizeof(glm::vec4) * 2,	0);
		pipelineLayoutCI.pushConstantRangeCount = 1;
		pipelineLayoutCI.pPushConstantRanges = &pushConstantRange;
		VK_CHECK_RESULT(vkCreatePipelineLayout(device, &pipelineLayoutCI, nullptr, &pipelineLayout));

		VkDescriptorSetAllocateInfo descriptorSetAllocateInfo = vks::initializers::descriptorSetAllocateInfo(descriptorPool, &descriptorSetLayout, 1);
		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &descriptorSetAllocateInfo, &descriptorSet));
		std::vector<VkWriteDescriptorSet> writeDescriptorSets = {
			vks::initializers::writeDescriptorSet(descriptorSet, VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 0, &uniformBuffer.descriptor)
		};
		vkUpdateDescriptorSets(device, writeDescriptorSets.size(), writeDescriptorSets.data(), 0, NULL);
	}

	void preparePipelines()
	{
		const std::vector<VkDynamicState> dynamicStateEnables = { VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR };

		VkPipelineInputAssemblyStateCreateInfo inputAssemblyStateCI = vks::initializers::pipelineInputAssemblyStateCreateInfo(VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST, 0, VK_FALSE);
		VkPipelineRasterizationStateCreateInfo rasterizationStateCI = vks::initializers::pipelineRasterizationStateCreateInfo(VK_POLYGON_MODE_FILL, VK_CULL_MODE_BACK_BIT, VK_FRONT_FACE_CLOCKWISE, 0);
		VkPipelineColorBlendAttachmentState blendAttachmentState = vks::initializers::pipelineColorBlendAttachmentState(0xf, VK_FALSE);
		VkPipelineColorBlendStateCreateInfo colorBlendStateCI = vks::initializers::pipelineColorBlendStateCreateInfo(1, &blendAttachmentState);
		VkPipelineDepthStencilStateCreateInfo depthStencilStateCI = vks::initializers::pipelineDepthStencilStateCreateInfo(VK_TRUE, VK_TRUE, VK_COMPARE_OP_LESS_OR_EQUAL);
		VkPipelineViewportStateCreateInfo viewportStateCI = vks::initializers::pipelineViewportStateCreateInfo(1, 1, 0);
		VkPipelineMultisampleStateCreateInfo multisampleStateCI = vks::initializers::pipelineMultisampleStateCreateInfo(VK_SAMPLE_COUNT_1_BIT, 0);
		VkPipelineDynamicStateCreateInfo dynamicStateCI = vks::initializers::pipelineDynamicStateCreateInfo(dynamicStateEnables.data(), static_cast<uint32_t>(dynamicStateEnables.size()), 0);

		// Vertex bindings and attributes
		const std::vector<VkVertexInputBindingDescription> vertexInputBindings = {
			vks::initializers::vertexInputBindingDescription(0, vertexLayout.stride(), VK_VERTEX_INPUT_RATE_VERTEX),
		};
		const std::vector<VkVertexInputAttributeDescription> vertexInputAttributes = {
			vks::initializers::vertexInputAttributeDescription(0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0),					// Location 0: Position			
			vks::initializers::vertexInputAttributeDescription(0, 1, VK_FORMAT_R32G32B32_SFLOAT, sizeof(float) * 3),	// Location 1: Normal
			vks::initializers::vertexInputAttributeDescription(0, 2, VK_FORMAT_R32G32B32_SFLOAT, sizeof(float) * 6),	// Location 3: Color
		};
		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 pipelineCreateInfoCI = vks::initializers::pipelineCreateInfo(pipelineLayout, renderPass, 0);
		pipelineCreateInfoCI.pVertexInputState = &vertexInputState;
		pipelineCreateInfoCI.pInputAssemblyState = &inputAssemblyStateCI;
		pipelineCreateInfoCI.pRasterizationState = &rasterizationStateCI;
		pipelineCreateInfoCI.pColorBlendState = &colorBlendStateCI;
		pipelineCreateInfoCI.pMultisampleState = &multisampleStateCI;
		pipelineCreateInfoCI.pViewportState = &viewportStateCI;
		pipelineCreateInfoCI.pDepthStencilState = &depthStencilStateCI;
		pipelineCreateInfoCI.pDynamicState = &dynamicStateCI;

		const std::array<VkPipelineShaderStageCreateInfo, 2> shaderStages = {
			loadShader(getAssetPath() + "shaders/conditionalrender/model.vert.spv", VK_SHADER_STAGE_VERTEX_BIT),
			loadShader(getAssetPath() + "shaders/conditionalrender/model.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT)
		};

		pipelineCreateInfoCI.stageCount = static_cast<uint32_t>(shaderStages.size());
		pipelineCreateInfoCI.pStages = shaderStages.data();

		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCreateInfoCI, nullptr, &pipeline));
	}

	void prepareUniformBuffers()
	{
		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)));
		VK_CHECK_RESULT(uniformBuffer.map());
		updateUniformBuffers();
	}

	void updateUniformBuffers()
	{
		uboVS.projection = camera.matrices.perspective;
		uboVS.modelview = camera.matrices.view;
		memcpy(uniformBuffer.mapped, &uboVS, sizeof(uboVS));
	}

	void updateConditionalBuffer()
	{
		memcpy(conditionalBuffer.mapped, &conditionalVisibility, sizeof(conditionalVisibility));
	}

	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()
	{
		VulkanExampleBase::prepare();

		/*
			Extension specific functions
		*/

		/*
			Get the function pointer
			
			The conditional rendering functions are part of an extension so they have to be manually loaded 
		*/
		vkCmdBeginConditionalRenderingEXT = (PFN_vkCmdBeginConditionalRenderingEXT)vkGetDeviceProcAddr(device, "vkCmdBeginConditionalRenderingEXT");
		if (!vkCmdBeginConditionalRenderingEXT) {
			vks::tools::exitFatal("Could not get a valid function pointer for vkCmdBeginConditionalRenderingEXT", -1);
		}

		vkCmdEndConditionalRenderingEXT = (PFN_vkCmdEndConditionalRenderingEXT)vkGetDeviceProcAddr(device, "vkCmdEndConditionalRenderingEXT");
		if (!vkCmdEndConditionalRenderingEXT) {
			vks::tools::exitFatal("Could not get a valid function pointer for vkCmdEndConditionalRenderingEXT", -1);
		}

		/*
			Get conditional rendering features
		*/
		PFN_vkGetPhysicalDeviceFeatures2KHR vkGetPhysicalDeviceFeatures2KHR = reinterpret_cast<PFN_vkGetPhysicalDeviceFeatures2KHR>(vkGetInstanceProcAddr(instance, "vkGetPhysicalDeviceFeatures2KHR"));
		if (!vkGetPhysicalDeviceFeatures2KHR) {
			vks::tools::exitFatal("Could not get a valid function pointer for vkGetPhysicalDeviceFeatures2KHR", -1);
		}
		VkPhysicalDeviceFeatures2KHR deviceFeatures2{};
		conditionalRenderingFeatures.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CONDITIONAL_RENDERING_FEATURES_EXT;
		deviceFeatures2.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2_KHR;
		deviceFeatures2.pNext = &conditionalRenderingFeatures;
		vkGetPhysicalDeviceFeatures2KHR(physicalDevice, &deviceFeatures2);

		/*
			Create the buffer that contains the conditional rendering information
			
			A single conditional value is 32 bits and if it's zero the rendering commands are discarded
			This sample renders multiple rows of objects conditionally, so we setup a buffer with one value per row
		*/
		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_CONDITIONAL_RENDERING_BIT_EXT,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			&conditionalBuffer,
			sizeof(uint32_t) * MODEL_ROWS));

		/*
			Copy visibility data
		*/
		for (auto i = 0; i < conditionalVisibility.size(); i++) {
			conditionalVisibility[i] = 1;
		}
		VK_CHECK_RESULT(conditionalBuffer.map());
		memcpy(conditionalBuffer.mapped, &conditionalVisibility, sizeof(conditionalVisibility));

		/*
			End of extension specific functions
		*/

		loadAssets();
		prepareUniformBuffers();
		setupDescriptorSets();
		preparePipelines();
		buildCommandBuffers();
		prepared = true;
	}

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

	virtual void viewChanged()
	{
		updateUniformBuffers();
	}

	virtual void OnUpdateUIOverlay(vks::UIOverlay *overlay)
	{
		if (overlay->header("Visibility")) {
			for (uint32_t i = 0; i < MODEL_ROWS; i++) {
				if (overlay->checkBox(std::to_string(i).c_str(), &conditionalVisibility[i])) {
					updateConditionalBuffer();
				};
				if (i < MODEL_ROWS - 1) { ImGui::SameLine(); };
			}
		}
		if (overlay->header("Device properties")) {
			overlay->text("conditional rendering: %s", conditionalRenderingFeatures.conditionalRendering ? "true" : "false");
			overlay->text("inherited conditional rendering: %s", conditionalRenderingFeatures.inheritedConditionalRendering ? "true" : "false");
		}

	}

};

VULKAN_EXAMPLE_MAIN()