Code cleanup, additional comments

examples/dynamicrendering/dynamicrendering.cpp

@@ -1,5 +1,5 @@
 /*
- * Vulkan Example - Using VK_KHR_dynamic_rendering for rendering without framebuffers and render passes (wip)
+ * Vulkan Example - Using VK_KHR_dynamic_rendering for rendering without framebuffers and render passes
  *
  * Copyright (C) 2022-2023 by Sascha Willems - www.saschawillems.de
  *
@@ -14,10 +14,10 @@
 class VulkanExample : public VulkanExampleBase
 {
 public:
-	PFN_vkCmdBeginRenderingKHR vkCmdBeginRenderingKHR;
+	PFN_vkCmdBeginRenderingKHR vkCmdBeginRenderingKHR{ VK_NULL_HANDLE };
-	PFN_vkCmdEndRenderingKHR vkCmdEndRenderingKHR;
+	PFN_vkCmdEndRenderingKHR vkCmdEndRenderingKHR{ VK_NULL_HANDLE };
 
-	VkPhysicalDeviceDynamicRenderingFeaturesKHR dynamicRenderingFeaturesKHR{};
+	VkPhysicalDeviceDynamicRenderingFeaturesKHR enabledDynamicRenderingFeaturesKHR{};
 
 	vkglTF::Model model;
 
@@ -28,10 +28,10 @@ public:
 	} uniformData;
 	vks::Buffer uniformBuffer;
 
-	VkPipeline pipeline;
+	VkPipeline pipeline{ VK_NULL_HANDLE };
-	VkPipelineLayout pipelineLayout;
+	VkPipelineLayout pipelineLayout{ VK_NULL_HANDLE };
-	VkDescriptorSet descriptorSet;
+	VkDescriptorSet descriptorSet{ VK_NULL_HANDLE };
-	VkDescriptorSetLayout descriptorSetLayout;
+	VkDescriptorSetLayout descriptorSetLayout{ VK_NULL_HANDLE };
 
 	VulkanExample() : VulkanExampleBase(ENABLE_VALIDATION)
 	{
@@ -43,14 +43,18 @@ public:
 
 		enabledInstanceExtensions.push_back(VK_KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2_EXTENSION_NAME);
 
+		// The sample uses the extension (instead of Vulkan 1.2, where dynamic rendering is core)
 		enabledDeviceExtensions.push_back(VK_KHR_DYNAMIC_RENDERING_EXTENSION_NAME);
-		
-		// Since we are not requiring Vulkan 1.2, we need to enable some additional extensios as required per the spec
 		enabledDeviceExtensions.push_back(VK_KHR_MAINTENANCE2_EXTENSION_NAME);
 		enabledDeviceExtensions.push_back(VK_KHR_MULTIVIEW_EXTENSION_NAME);
 		enabledDeviceExtensions.push_back(VK_KHR_CREATE_RENDERPASS_2_EXTENSION_NAME);
 		enabledDeviceExtensions.push_back(VK_KHR_DEPTH_STENCIL_RESOLVE_EXTENSION_NAME);
 
+		// in addition to the extension, the feature needs to be explicitly enabled too by chaining the extension structure into device creation
+		enabledDynamicRenderingFeaturesKHR.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DYNAMIC_RENDERING_FEATURES_KHR;
+		enabledDynamicRenderingFeaturesKHR.dynamicRendering = VK_TRUE;
+
+		deviceCreatepNextChain = &enabledDynamicRenderingFeaturesKHR;
 	}
 
 	~VulkanExample()
@@ -81,11 +85,6 @@ public:
 		if (deviceFeatures.samplerAnisotropy) {
 			enabledFeatures.samplerAnisotropy = VK_TRUE;
 		};
-
-		dynamicRenderingFeaturesKHR.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DYNAMIC_RENDERING_FEATURES_KHR;
-		dynamicRenderingFeaturesKHR.dynamicRendering = VK_TRUE;
-
-		deviceCreatepNextChain = &dynamicRenderingFeaturesKHR;
 	}
 
 	void loadAssets()
@@ -102,7 +101,8 @@ public:
 		{
 			VK_CHECK_RESULT(vkBeginCommandBuffer(drawCmdBuffers[i], &cmdBufInfo));
 
-			// Transition color and depth images for drawing
+			// With dynamic rendering there are no subpass dependencies, so we need to take care of proper layout transitions by using barriers
+			// This set of barriers prepares the color and depth images for output
 			vks::tools::insertImageMemoryBarrier(
 				drawCmdBuffers[i],
 				swapChain.buffers[i].image,
@@ -171,7 +171,7 @@ public:
 			// End dynamic rendering
 			vkCmdEndRenderingKHR(drawCmdBuffers[i]);
 
-			// Transition color image for presentation
+			// This set of barriers prepares the color image for presentation, we don't need to care for the depth image
 			vks::tools::insertImageMemoryBarrier(
 				drawCmdBuffers[i],
 				swapChain.buffers[i].image,
@@ -187,46 +187,22 @@ public:
 		}
 	}
 
-	void draw()
+	void setupDescriptors()
-	{
+	{	
-		VulkanExampleBase::prepareFrame();
+		// Pool
-		submitInfo.commandBufferCount = 1;
-		submitInfo.pCommandBuffers = &drawCmdBuffers[currentBuffer];
-		VK_CHECK_RESULT(vkQueueSubmit(queue, 1, &submitInfo, VK_NULL_HANDLE));
-		VulkanExampleBase::submitFrame();
-	}
-
-	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 =
+		VkDescriptorPoolCreateInfo descriptorPoolInfo = vks::initializers::descriptorPoolCreateInfo(poolSizes, 1);
-			vks::initializers::descriptorPoolCreateInfo(poolSizes, 1);
 		VK_CHECK_RESULT(vkCreateDescriptorPool(device, &descriptorPoolInfo, nullptr, &descriptorPool));
-	}
+		// Layout
-
-	void setupDescriptorSetLayout()
-	{
 		const 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);
 		VK_CHECK_RESULT(vkCreateDescriptorSetLayout(device, &descriptorLayout, nullptr, &descriptorSetLayout));
-
+		// Set
-		// Layout uses set 0 for passing vertex shader ubo and set 1 for fragment shader images (taken from glTF model)
-		const std::vector<VkDescriptorSetLayout> setLayouts = {
-			descriptorSetLayout,
-			vkglTF::descriptorSetLayoutImage,
-		};
-		VkPipelineLayoutCreateInfo pPipelineLayoutCreateInfo = vks::initializers::pipelineLayoutCreateInfo(setLayouts.data(), 2);
-		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 = {
@@ -238,6 +214,16 @@ public:
 
 	void preparePipelines()
 	{
+		// Layout
+		// Uses set 0 for passing vertex shader ubo and set 1 for fragment shader images (taken from glTF model)
+		const std::vector<VkDescriptorSetLayout> setLayouts = {
+			descriptorSetLayout,
+			vkglTF::descriptorSetLayoutImage,
+		};
+		VkPipelineLayoutCreateInfo pPipelineLayoutCreateInfo = vks::initializers::pipelineLayoutCreateInfo(setLayouts.data(), 2);
+		VK_CHECK_RESULT(vkCreatePipelineLayout(device, &pPipelineLayoutCreateInfo, nullptr, &pipelineLayout));
+
+		// Pipeline
 		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_NONE, VK_FRONT_FACE_COUNTER_CLOCKWISE, 0);
 		VkPipelineColorBlendAttachmentState blendAttachmentState = vks::initializers::pipelineColorBlendAttachmentState(0xf, VK_FALSE);
@@ -283,7 +269,6 @@ public:
 	{
 		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(uniformData), &uniformData));
 		VK_CHECK_RESULT(uniformBuffer.map());
-
 		updateUniformBuffers();
 	}
 
@@ -299,29 +284,33 @@ public:
 	{
 		VulkanExampleBase::prepare();
 
+		// Since we use an extension, we need to expliclity load the function pointers for extension related Vulkan commands
 		vkCmdBeginRenderingKHR = reinterpret_cast<PFN_vkCmdBeginRenderingKHR>(vkGetDeviceProcAddr(device, "vkCmdBeginRenderingKHR"));
 		vkCmdEndRenderingKHR = reinterpret_cast<PFN_vkCmdEndRenderingKHR>(vkGetDeviceProcAddr(device, "vkCmdEndRenderingKHR"));
 
 		loadAssets();
 		prepareUniformBuffers();
-		setupDescriptorSetLayout();
+		setupDescriptors();
 		preparePipelines();
-		setupDescriptorPool();
-		setupDescriptorSet();
 		buildCommandBuffers();
 		prepared = true;
 	}
 
+	void draw()
+	{
+		VulkanExampleBase::prepareFrame();
+		submitInfo.commandBufferCount = 1;
+		submitInfo.pCommandBuffers = &drawCmdBuffers[currentBuffer];
+		VK_CHECK_RESULT(vkQueueSubmit(queue, 1, &submitInfo, VK_NULL_HANDLE));
+		VulkanExampleBase::submitFrame();
+	}
+
 	virtual void render()
 	{
 		if (!prepared)
 			return;
-		draw();
-	}
-
-	virtual void viewChanged()
-	{
 		updateUniformBuffers();
+		draw();
 	}
 };