procedural-3d-engine/screenshot/screenshot.cpp

/*
* 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 <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 VERTEX_BUFFER_BIND_ID 0
#define ENABLE_VALIDATION false

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

	struct {
		vks::Model object;
	} models;

	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;

	VulkanExample() : VulkanExampleBase(ENABLE_VALIDATION)
	{
		title = "Vulkan Example - Screenshot";
		enableTextOverlay = 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, -2.0f));
	}

	~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);

		models.object.destroy();

		uniformBuffer.destroy();
	}

	void loadAssets()
	{
		models.object.loadFromFile(getAssetPath() + "models/chinesedragon.dae", vertexLayout, 0.1f, vulkanDevice, queue);
	}

	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);

			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);

			vkCmdDrawIndexed(drawCmdBuffers[i], models.object.indexCount, 1, 0, 0, 0);

			vkCmdEndRenderPass(drawCmdBuffers[i]);

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

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

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

		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, 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_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.data(),
				dynamicStateEnables.size(),
				0);

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

		std::array<VkPipelineShaderStageCreateInfo, 2> shaderStages;

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

		// Vertex bindings and attributes
		// Binding description
		std::vector<VkVertexInputBindingDescription> vertexInputBindings = {
			vks::initializers::vertexInputBindingDescription(0, vertexLayout.stride(), VK_VERTEX_INPUT_RATE_VERTEX),
		};

		// Attribute descriptions
		std::vector<VkVertexInputAttributeDescription> vertexInputAttributes = {
			vks::initializers::vertexInputAttributeDescription(0, 0, VK_FORMAT_R32G32B32_SFLOAT, 0),					// Position
			vks::initializers::vertexInputAttributeDescription(0, 1, VK_FORMAT_R32G32B32_SFLOAT, sizeof(float) * 3),	// Normal
			vks::initializers::vertexInputAttributeDescription(0, 2, VK_FORMAT_R32G32B32_SFLOAT, sizeof(float) * 6),	// 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();

		pipelineCreateInfo.pVertexInputState = &vertexInputState;

		// Mesh rendering pipeline
		shaderStages[0] = loadShader(getAssetPath() + "shaders/screenshot/mesh.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
		shaderStages[1] = loadShader(getAssetPath() + "shaders/screenshot/mesh.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCreateInfo, 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));

		updateUniformBuffers();
	}

	void updateUniformBuffers()
	{
		uboVS.projection = camera.matrices.perspective;
		uboVS.view = camera.matrices.view;
		uboVS.model = glm::mat4(1.0f);

		VK_CHECK_RESULT(uniformBuffer.map());
		uniformBuffer.copyTo(&uboVS, sizeof(uboVS));
		uniformBuffer.unmap();
	}

	// Take a screenshot for the curretn 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)
	{
		// Get format properties for the swapchain color format
		VkFormatProperties formatProps;

		bool supportsBlit = true;

		// Check blit support for source and destination

		// 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 imgCreateInfo(vks::initializers::imageCreateInfo());
		imgCreateInfo.imageType = VK_IMAGE_TYPE_2D;
		// Note that vkCmdBlitImage (if supported) will also do format conversions if the swapchain color format would differ
		imgCreateInfo.format = VK_FORMAT_R8G8B8A8_UNORM;
		imgCreateInfo.extent.width = width;
		imgCreateInfo.extent.height = height;
		imgCreateInfo.extent.depth = 1;
		imgCreateInfo.arrayLayers = 1;
		imgCreateInfo.mipLevels = 1;
		imgCreateInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
		imgCreateInfo.samples = VK_SAMPLE_COUNT_1_BIT;
		imgCreateInfo.tiling = VK_IMAGE_TILING_LINEAR;
		imgCreateInfo.usage = VK_IMAGE_USAGE_TRANSFER_DST_BIT;
		// Create the image
		VkImage dstImage;
		VK_CHECK_RESULT(vkCreateImage(device, &imgCreateInfo, 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);

		VkImageMemoryBarrier imageMemoryBarrier = vks::initializers::imageMemoryBarrier();
		
		// 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{};
		subResource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
		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);
	}

	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 keyPressed(uint32_t keyCode)
	{
		switch (keyCode)
		{
		case KEY_F2:
		case GAMEPAD_BUTTON_A:
			saveScreenshot("screenshot.ppm");
			break;
		}
	}

	virtual void getOverlayText(VulkanTextOverlay *textOverlay)
	{
#if defined(__ANDROID__)
		textOverlay->addText("\"Button A\" to save screenshot", 5.0f, 85.0f, VulkanTextOverlay::alignLeft);
#else
		textOverlay->addText("\"F2\" to save screenshot", 5.0f, 85.0f, VulkanTextOverlay::alignLeft);
#endif
	}
};

VULKAN_EXAMPLE_MAIN()