/*
* Vulkan Example - Taking screenshots
*
* 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

class VulkanExample : public VulkanExampleBase
{
public:
	vkglTF::Model model;
	vks::Buffer uniformBuffer;

	struct {
		glm::mat4 projection;
		glm::mat4 model;
		glm::mat4 view;
		int32_t texIndex = 0;
	} uboVS;

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

	bool screenshotSaved = false;

	VulkanExample() : VulkanExampleBase(ENABLE_VALIDATION)
	{
		title = "Saving framebuffer to screenshot";
		settings.overlay = true;

		camera.type = Camera::CameraType::lookat;
		camera.setPerspective(60.0f, (float)width / (float)height, 0.1f, 512.0f);
		camera.setRotation(glm::vec3(-25.0f, 23.75f, 0.0f));
		camera.setTranslation(glm::vec3(0.0f, 0.0f, -3.0f));
	}

	~VulkanExample()
	{
		vkDestroyPipeline(device, pipeline, nullptr);
		vkDestroyPipelineLayout(device, pipelineLayout, nullptr);
		vkDestroyDescriptorSetLayout(device, descriptorSetLayout, nullptr);
		uniformBuffer.destroy();
	}

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

	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));

			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, pipeline);
			model.draw(drawCmdBuffers[i]);

			drawUI(drawCmdBuffers[i]);

			vkCmdEndRenderPass(drawCmdBuffers[i]);

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

	void setupDescriptorPool()
	{
		std::vector<VkDescriptorPoolSize> poolSizes = {
			vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 1),
		};
		VkDescriptorPoolCreateInfo descriptorPoolInfo = vks::initializers::descriptorPoolCreateInfo(poolSizes, 2);
		VK_CHECK_RESULT(vkCreateDescriptorPool(device, &descriptorPoolInfo, nullptr, &descriptorPool));
	}

	void setupDescriptorSetLayout()
	{
		std::vector<VkDescriptorSetLayoutBinding> setLayoutBindings = {
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, VK_SHADER_STAGE_VERTEX_BIT, 0),		// Binding 0: Vertex shader uniform buffer
		};
		VkDescriptorSetLayoutCreateInfo descriptorLayout = vks::initializers::descriptorSetLayoutCreateInfo(setLayoutBindings);
		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));
		std::vector<VkWriteDescriptorSet> writeDescriptorSets = {
			vks::initializers::writeDescriptorSet(descriptorSet, VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 0, &uniformBuffer.descriptor),	// Binding 0: Vertex shader uniform buffer
		};
		vkUpdateDescriptorSets(device, writeDescriptorSets.size(), writeDescriptorSets.data(), 0, nullptr);
	}

	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 = {
			loadShader(getShadersPath() + "screenshot/mesh.vert.spv", VK_SHADER_STAGE_VERTEX_BIT),
			loadShader(getShadersPath() + "screenshot/mesh.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT),
		};

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

	void prepareUniformBuffers()
	{
		// Vertex shader uniform buffer block
		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.view = camera.matrices.view;
		uboVS.model = glm::mat4(1.0f);
		uniformBuffer.copyTo(&uboVS, sizeof(uboVS));
	}

	// Take a screenshot from the current swapchain image
	// This is done using a blit from the swapchain image to a linear image whose memory content is then saved as a ppm image
	// Getting the image date directly from a swapchain image wouldn't work as they're usually stored in an implementation dependant optimal tiling format
	// Note: This requires the swapchain images to be created with the VK_IMAGE_USAGE_TRANSFER_SRC_BIT flag (see VulkanSwapChain::create)
	void saveScreenshot(const char *filename)
	{
		screenshotSaved = false;
		bool supportsBlit = true;

		// Check blit support for source and destination
		VkFormatProperties formatProps;

		// Check if the device supports blitting from optimal images (the swapchain images are in optimal format)
		vkGetPhysicalDeviceFormatProperties(physicalDevice, swapChain.colorFormat, &formatProps);
		if (!(formatProps.optimalTilingFeatures & VK_FORMAT_FEATURE_BLIT_SRC_BIT)) {
			std::cerr << "Device does not support blitting from optimal tiled images, using copy instead of blit!" << std::endl;
			supportsBlit = false;
		}

		// Check if the device supports blitting to linear images
		vkGetPhysicalDeviceFormatProperties(physicalDevice, VK_FORMAT_R8G8B8A8_UNORM, &formatProps);
		if (!(formatProps.linearTilingFeatures & VK_FORMAT_FEATURE_BLIT_DST_BIT)) {
			std::cerr << "Device does not support blitting to linear tiled images, using copy instead of blit!" << std::endl;
			supportsBlit = false;
		}

		// Source for the copy is the last rendered swapchain image
		VkImage srcImage = swapChain.images[currentBuffer];

		// Create the linear tiled destination image to copy to and to read the memory from
		VkImageCreateInfo imageCreateCI(vks::initializers::imageCreateInfo());
		imageCreateCI.imageType = VK_IMAGE_TYPE_2D;
		// Note that vkCmdBlitImage (if supported) will also do format conversions if the swapchain color format would differ
		imageCreateCI.format = VK_FORMAT_R8G8B8A8_UNORM;
		imageCreateCI.extent.width = width;
		imageCreateCI.extent.height = height;
		imageCreateCI.extent.depth = 1;
		imageCreateCI.arrayLayers = 1;
		imageCreateCI.mipLevels = 1;
		imageCreateCI.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
		imageCreateCI.samples = VK_SAMPLE_COUNT_1_BIT;
		imageCreateCI.tiling = VK_IMAGE_TILING_LINEAR;
		imageCreateCI.usage = VK_IMAGE_USAGE_TRANSFER_DST_BIT;
		// Create the image
		VkImage dstImage;
		VK_CHECK_RESULT(vkCreateImage(device, &imageCreateCI, nullptr, &dstImage));
		// Create memory to back up the image
		VkMemoryRequirements memRequirements;
		VkMemoryAllocateInfo memAllocInfo(vks::initializers::memoryAllocateInfo());
		VkDeviceMemory dstImageMemory;
		vkGetImageMemoryRequirements(device, dstImage, &memRequirements);
		memAllocInfo.allocationSize = memRequirements.size;
		// Memory must be host visible to copy from
		memAllocInfo.memoryTypeIndex = vulkanDevice->getMemoryType(memRequirements.memoryTypeBits, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT);
		VK_CHECK_RESULT(vkAllocateMemory(device, &memAllocInfo, nullptr, &dstImageMemory));
		VK_CHECK_RESULT(vkBindImageMemory(device, dstImage, dstImageMemory, 0));

		// Do the actual blit from the swapchain image to our host visible destination image
		VkCommandBuffer copyCmd = vulkanDevice->createCommandBuffer(VK_COMMAND_BUFFER_LEVEL_PRIMARY, true);

		// Transition destination image to transfer destination layout
		vks::tools::insertImageMemoryBarrier(
			copyCmd,
			dstImage,
			0,
			VK_ACCESS_TRANSFER_WRITE_BIT,
			VK_IMAGE_LAYOUT_UNDEFINED,
			VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
			VK_PIPELINE_STAGE_TRANSFER_BIT,
			VK_PIPELINE_STAGE_TRANSFER_BIT,
			VkImageSubresourceRange{ VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 });

		// Transition swapchain image from present to transfer source layout
		vks::tools::insertImageMemoryBarrier(
			copyCmd,
			srcImage,
			VK_ACCESS_MEMORY_READ_BIT,
			VK_ACCESS_TRANSFER_READ_BIT,
			VK_IMAGE_LAYOUT_PRESENT_SRC_KHR,
			VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
			VK_PIPELINE_STAGE_TRANSFER_BIT,
			VK_PIPELINE_STAGE_TRANSFER_BIT,
			VkImageSubresourceRange{ VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 });

		// If source and destination support blit we'll blit as this also does automatic format conversion (e.g. from BGR to RGB)
		if (supportsBlit)
		{
			// Define the region to blit (we will blit the whole swapchain image)
			VkOffset3D blitSize;
			blitSize.x = width;
			blitSize.y = height;
			blitSize.z = 1;
			VkImageBlit imageBlitRegion{};
			imageBlitRegion.srcSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
			imageBlitRegion.srcSubresource.layerCount = 1;
			imageBlitRegion.srcOffsets[1] = blitSize;
			imageBlitRegion.dstSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
			imageBlitRegion.dstSubresource.layerCount = 1;
			imageBlitRegion.dstOffsets[1] = blitSize;

			// Issue the blit command
			vkCmdBlitImage(
				copyCmd,
				srcImage, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
				dstImage, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
				1,
				&imageBlitRegion,
				VK_FILTER_NEAREST);
		}
		else
		{
			// Otherwise use image copy (requires us to manually flip components)
			VkImageCopy imageCopyRegion{};
			imageCopyRegion.srcSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
			imageCopyRegion.srcSubresource.layerCount = 1;
			imageCopyRegion.dstSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
			imageCopyRegion.dstSubresource.layerCount = 1;
			imageCopyRegion.extent.width = width;
			imageCopyRegion.extent.height = height;
			imageCopyRegion.extent.depth = 1;

			// Issue the copy command
			vkCmdCopyImage(
				copyCmd,
				srcImage, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
				dstImage, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
				1,
				&imageCopyRegion);
		}

		// Transition destination image to general layout, which is the required layout for mapping the image memory later on
		vks::tools::insertImageMemoryBarrier(
			copyCmd,
			dstImage,
			VK_ACCESS_TRANSFER_WRITE_BIT,
			VK_ACCESS_MEMORY_READ_BIT,
			VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
			VK_IMAGE_LAYOUT_GENERAL,
			VK_PIPELINE_STAGE_TRANSFER_BIT,
			VK_PIPELINE_STAGE_TRANSFER_BIT,
			VkImageSubresourceRange{ VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 });

		// Transition back the swap chain image after the blit is done
		vks::tools::insertImageMemoryBarrier(
			copyCmd,
			srcImage,
			VK_ACCESS_TRANSFER_READ_BIT,
			VK_ACCESS_MEMORY_READ_BIT,
			VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,
			VK_IMAGE_LAYOUT_PRESENT_SRC_KHR,
			VK_PIPELINE_STAGE_TRANSFER_BIT,
			VK_PIPELINE_STAGE_TRANSFER_BIT,
			VkImageSubresourceRange{ VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 });

		vulkanDevice->flushCommandBuffer(copyCmd, queue);

		// Get layout of the image (including row pitch)
		VkImageSubresource subResource { VK_IMAGE_ASPECT_COLOR_BIT, 0, 0 };
		VkSubresourceLayout subResourceLayout;
		vkGetImageSubresourceLayout(device, dstImage, &subResource, &subResourceLayout);

		// Map image memory so we can start copying from it
		const char* data;
		vkMapMemory(device, dstImageMemory, 0, VK_WHOLE_SIZE, 0, (void**)&data);
		data += subResourceLayout.offset;

		std::ofstream file(filename, std::ios::out | std::ios::binary);

		// ppm header
		file << "P6\n" << width << "\n" << height << "\n" << 255 << "\n";

		// If source is BGR (destination is always RGB) and we can't use blit (which does automatic conversion), we'll have to manually swizzle color components
		bool colorSwizzle = false;
		// Check if source is BGR
		// Note: Not complete, only contains most common and basic BGR surface formats for demonstation purposes
		if (!supportsBlit)
		{
			std::vector<VkFormat> formatsBGR = { VK_FORMAT_B8G8R8A8_SRGB, VK_FORMAT_B8G8R8A8_UNORM, VK_FORMAT_B8G8R8A8_SNORM };
			colorSwizzle = (std::find(formatsBGR.begin(), formatsBGR.end(), swapChain.colorFormat) != formatsBGR.end());
		}

		// ppm binary pixel data
		for (uint32_t y = 0; y < height; y++)
		{
			unsigned int *row = (unsigned int*)data;
			for (uint32_t x = 0; x < width; x++)
			{
				if (colorSwizzle)
				{
					file.write((char*)row+2, 1);
					file.write((char*)row+1, 1);
					file.write((char*)row, 1);
				}
				else
				{
					file.write((char*)row, 3);
				}
				row++;
			}
			data += subResourceLayout.rowPitch;
		}
		file.close();

		std::cout << "Screenshot saved to disk" << std::endl;

		// Clean up resources
		vkUnmapMemory(device, dstImageMemory);
		vkFreeMemory(device, dstImageMemory, nullptr);
		vkDestroyImage(device, dstImage, nullptr);

		screenshotSaved = true;
	}

	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();
		prepareUniformBuffers();
		setupDescriptorSetLayout();
		preparePipelines();
		setupDescriptorPool();
		setupDescriptorSet();
		buildCommandBuffers();
		prepared = true;
	}

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

	virtual void viewChanged()
	{
		updateUniformBuffers();
	}

	virtual void OnUpdateUIOverlay(vks::UIOverlay *overlay)
	{
		if (overlay->header("Functions")) {
			if (overlay->button("Take screenshot")) {
				saveScreenshot("screenshot.ppm");
			}
			if (screenshotSaved) {
				overlay->text("Screenshot saved as screenshot.ppm");
			}
		}
	}

};

VULKAN_EXAMPLE_MAIN()