Build command buffers for pre and post present barriers only once (instead of every frame)

base/vulkanexamplebase.cpp

@@ -121,28 +121,28 @@ void VulkanExampleBase::createCommandBuffers()
 	// them each frame, we use one per frame buffer
 
 	drawCmdBuffers.resize(swapChain.imageCount);
+	prePresentCmdBuffers.resize(swapChain.imageCount);
+	postPresentCmdBuffers.resize(swapChain.imageCount);
 
 	VkCommandBufferAllocateInfo cmdBufAllocateInfo =
 		vkTools::initializers::commandBufferAllocateInfo(
 			cmdPool,
 			VK_COMMAND_BUFFER_LEVEL_PRIMARY,
-			(uint32_t)drawCmdBuffers.size());
+			static_cast<uint32_t>(drawCmdBuffers.size()));
 
 	VK_CHECK_RESULT(vkAllocateCommandBuffers(device, &cmdBufAllocateInfo, drawCmdBuffers.data()));
 
 	// Command buffers for submitting present barriers
-	cmdBufAllocateInfo.commandBufferCount = 1;
+	// One pre and post present buffer per swap chain image
-	// Pre present
+	VK_CHECK_RESULT(vkAllocateCommandBuffers(device, &cmdBufAllocateInfo, prePresentCmdBuffers.data()));
-	VK_CHECK_RESULT(vkAllocateCommandBuffers(device, &cmdBufAllocateInfo, &prePresentCmdBuffer));
+	VK_CHECK_RESULT(vkAllocateCommandBuffers(device, &cmdBufAllocateInfo, postPresentCmdBuffers.data()));
-	// Post present
-	VK_CHECK_RESULT(vkAllocateCommandBuffers(device, &cmdBufAllocateInfo, &postPresentCmdBuffer));
 }
 
 void VulkanExampleBase::destroyCommandBuffers()
 {
-	vkFreeCommandBuffers(device, cmdPool, (uint32_t)drawCmdBuffers.size(), drawCmdBuffers.data());
+	vkFreeCommandBuffers(device, cmdPool, static_cast<uint32_t>(drawCmdBuffers.size()), drawCmdBuffers.data());
-	vkFreeCommandBuffers(device, cmdPool, 1, &prePresentCmdBuffer);
+	vkFreeCommandBuffers(device, cmdPool, static_cast<uint32_t>(drawCmdBuffers.size()), prePresentCmdBuffers.data());
-	vkFreeCommandBuffers(device, cmdPool, 1, &postPresentCmdBuffer);
+	vkFreeCommandBuffers(device, cmdPool, static_cast<uint32_t>(drawCmdBuffers.size()), postPresentCmdBuffers.data());
 }
 
 void VulkanExampleBase::createSetupCommandBuffer()
@@ -256,6 +256,7 @@ void VulkanExampleBase::prepare()
 	createSetupCommandBuffer();
 	setupSwapChain();
 	createCommandBuffers();
+	buildPresentCommandBuffers();
 	setupDepthStencil();
 	setupRenderPass();
 	createPipelineCache();
@@ -645,7 +646,7 @@ void VulkanExampleBase::prepareFrame()
 {
 	// Acquire the next image from the swap chaing
 	VK_CHECK_RESULT(swapChain.acquireNextImage(semaphores.presentComplete, &currentBuffer));
-	
+/*	
 	// Insert a post present image barrier to transform the image back to a
 	// color attachment that our render pass can write to
 	// We always use undefined image layout as the source as it doesn't actually matter
@@ -673,9 +674,12 @@ void VulkanExampleBase::prepareFrame()
 		1, &postPresentBarrier);
 
 	VK_CHECK_RESULT(vkEndCommandBuffer(postPresentCmdBuffer));
+*/
+
+	// Submit post present image barrier to transform the image back to a color attachment that our render pass can write to
 	VkSubmitInfo submitInfo = vkTools::initializers::submitInfo();
 	submitInfo.commandBufferCount = 1;
-	submitInfo.pCommandBuffers = &postPresentCmdBuffer;
+	submitInfo.pCommandBuffers = &postPresentCmdBuffers[currentBuffer];
 	VK_CHECK_RESULT(vkQueueSubmit(queue, 1, &submitInfo, VK_NULL_HANDLE));
 }
 
@@ -715,6 +719,7 @@ void VulkanExampleBase::submitFrame()
 
 	// Submit a pre present image barrier to the queue
 	// Transforms the (framebuffer) image layout from color attachment to present(khr) for presenting to the swap chain
+	/*
 	VkCommandBufferBeginInfo cmdBufInfo = vkTools::initializers::commandBufferBeginInfo();
 	VK_CHECK_RESULT(vkBeginCommandBuffer(prePresentCmdBuffer, &cmdBufInfo));
 
@@ -738,9 +743,11 @@ void VulkanExampleBase::submitFrame()
 		1, &prePresentBarrier);
 
 	VK_CHECK_RESULT(vkEndCommandBuffer(prePresentCmdBuffer));
+	*/
+	// Submit pre present image barrier to transform the image from color attachment to present(khr) for presenting to the swap chain
 	VkSubmitInfo submitInfo = vkTools::initializers::submitInfo();
 	submitInfo.commandBufferCount = 1;
-	submitInfo.pCommandBuffers = &prePresentCmdBuffer;
+	submitInfo.pCommandBuffers = &prePresentCmdBuffers[currentBuffer];
 	VK_CHECK_RESULT(vkQueueSubmit(queue, 1, &submitInfo, VK_NULL_HANDLE));
 
 	VK_CHECK_RESULT(swapChain.queuePresent(queue, currentBuffer, submitTextOverlay ? semaphores.textOverlayComplete : semaphores.renderComplete));
@@ -1504,6 +1511,72 @@ void VulkanExampleBase::buildCommandBuffers()
 	// Can be overriden in derived class
 }
 
+void VulkanExampleBase::buildPresentCommandBuffers()
+{
+	VkCommandBufferBeginInfo cmdBufInfo = vkTools::initializers::commandBufferBeginInfo();
+
+	for (uint32_t i = 0; i < swapChain.imageCount; i++)
+	{
+		// Command buffer for post present barrier
+
+		// Insert a post present image barrier to transform the image back to a
+		// color attachment that our render pass can write to
+		// We always use undefined image layout as the source as it doesn't actually matter
+		// what is done with the previous image contents
+
+		VK_CHECK_RESULT(vkBeginCommandBuffer(postPresentCmdBuffers[i], &cmdBufInfo));
+
+		VkImageMemoryBarrier postPresentBarrier = vkTools::initializers::imageMemoryBarrier();
+		postPresentBarrier.srcAccessMask = 0;
+		postPresentBarrier.dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
+		postPresentBarrier.oldLayout = VK_IMAGE_LAYOUT_UNDEFINED;
+		postPresentBarrier.newLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
+		postPresentBarrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
+		postPresentBarrier.dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
+		postPresentBarrier.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
+		postPresentBarrier.image = swapChain.buffers[i].image;
+
+		vkCmdPipelineBarrier(
+			postPresentCmdBuffers[i],
+			VK_PIPELINE_STAGE_ALL_COMMANDS_BIT,
+			VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
+			0,
+			0, nullptr,
+			0, nullptr,
+			1, &postPresentBarrier);
+
+		VK_CHECK_RESULT(vkEndCommandBuffer(postPresentCmdBuffers[i]));
+
+		// Command buffers for pre present barrier
+
+		// Submit a pre present image barrier to the queue
+		// Transforms the (framebuffer) image layout from color attachment to present(khr) for presenting to the swap chain
+
+		VK_CHECK_RESULT(vkBeginCommandBuffer(prePresentCmdBuffers[i], &cmdBufInfo));
+
+		VkImageMemoryBarrier prePresentBarrier = vkTools::initializers::imageMemoryBarrier();
+		prePresentBarrier.srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
+		prePresentBarrier.dstAccessMask = VK_ACCESS_MEMORY_READ_BIT;
+		prePresentBarrier.oldLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
+		prePresentBarrier.newLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;
+		prePresentBarrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
+		prePresentBarrier.dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
+		prePresentBarrier.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
+		prePresentBarrier.image = swapChain.buffers[i].image;
+
+		vkCmdPipelineBarrier(
+			prePresentCmdBuffers[i],
+			VK_PIPELINE_STAGE_ALL_COMMANDS_BIT,
+			VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
+			VK_FLAGS_NONE,
+			0, nullptr, // No memory barriers,
+			0, nullptr, // No buffer barriers,
+			1, &prePresentBarrier);
+
+		VK_CHECK_RESULT(vkEndCommandBuffer(prePresentCmdBuffers[i]));
+	}
+}
+
 VkBool32 VulkanExampleBase::getMemoryType(uint32_t typeBits, VkFlags properties, uint32_t * typeIndex)
 {
 	for (uint32_t i = 0; i < 32; i++)
@@ -1719,6 +1792,7 @@ void VulkanExampleBase::windowResize()
 	destroyCommandBuffers();
 	createCommandBuffers();
 	buildCommandBuffers();
+	buildPresentCommandBuffers();
 
 	vkQueueWaitIdle(queue);
 	vkDeviceWaitIdle(device);

base/vulkanexamplebase.h

@@ -102,9 +102,9 @@ protected:
 	// Command buffer used for setup
 	VkCommandBuffer setupCmdBuffer = VK_NULL_HANDLE;
 	// Command buffer for submitting a post present image barrier
-	VkCommandBuffer postPresentCmdBuffer = VK_NULL_HANDLE;
+	std::vector<VkCommandBuffer> postPresentCmdBuffers = { VK_NULL_HANDLE };
-	// Command buffer for submitting a pre present image barrier
+	// Command buffers for submitting a pre present image barrier
-	VkCommandBuffer prePresentCmdBuffer = VK_NULL_HANDLE;
+	std::vector<VkCommandBuffer> prePresentCmdBuffers = { VK_NULL_HANDLE };
 	// Pipeline stage flags for the submit info structure
 	VkPipelineStageFlags submitPipelineStages = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
 	// Contains command buffers and semaphores to be presented to the queue
@@ -246,6 +246,9 @@ public:
 	// all command buffers that may reference this
 	virtual void buildCommandBuffers();
 
+	// Builds the command buffers used to submit the present barriers
+	void buildPresentCommandBuffers();
+
 	// Get memory type for a given memory allocation (flags and bits)
 	VkBool32 getMemoryType(uint32_t typeBits, VkFlags properties, uint32_t *typeIndex);
 	uint32_t getMemoryType(uint32_t typeBits, VkFlags properties);

triangle/triangle.cpp

@@ -292,13 +292,12 @@ public:
 
 			VK_CHECK_RESULT(vkEndCommandBuffer(drawCmdBuffers[i]));
 		}
-	}
 
-	void draw()
+		// Build command buffers for the post present image barrier for each swap chain image
+		// Note: The command Buffers are allocated in the base class
+
+		for (uint32_t i = 0; i < swapChain.imageCount; i++)
 		{
-		// Get next image in the swap chain (back/front buffer)
-		VK_CHECK_RESULT(swapChain.acquireNextImage(semaphores.presentComplete, &currentBuffer));
-
 			// Insert a post present image barrier to transform the image back to a
 			// color attachment that our render pass can write to
 			// We always use undefined image layout as the source as it doesn't actually matter
@@ -311,17 +310,17 @@ public:
 			postPresentBarrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
 			postPresentBarrier.dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
 			postPresentBarrier.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
-		postPresentBarrier.image = swapChain.buffers[currentBuffer].image;
+			postPresentBarrier.image = swapChain.buffers[i].image;
 
 			// Use dedicated command buffer from example base class for submitting the post present barrier
 			VkCommandBufferBeginInfo cmdBufInfo = {};
 			cmdBufInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
 
-		VK_CHECK_RESULT(vkBeginCommandBuffer(postPresentCmdBuffer, &cmdBufInfo));
+			VK_CHECK_RESULT(vkBeginCommandBuffer(postPresentCmdBuffers[i], &cmdBufInfo));
 
 			// Put post present barrier into command buffer
 			vkCmdPipelineBarrier(
-			postPresentCmdBuffer,
+				postPresentCmdBuffers[i],
 				VK_PIPELINE_STAGE_ALL_COMMANDS_BIT,
 				VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
 				VK_FLAGS_NONE,
@@ -329,13 +328,21 @@ public:
 				0, nullptr,
 				1, &postPresentBarrier);
 
-		VK_CHECK_RESULT(vkEndCommandBuffer(postPresentCmdBuffer));
+			VK_CHECK_RESULT(vkEndCommandBuffer(postPresentCmdBuffers[i]));
+		}
+	}
 
-		// Submit the image barrier to the current queue
+	void draw()
-		submitInfo = {};
+	{
+		// Get next image in the swap chain (back/front buffer)
+		VK_CHECK_RESULT(swapChain.acquireNextImage(semaphores.presentComplete, &currentBuffer));
+
+		// Submit the post present image barrier to transform the image back to a color attachment
+		// that can be used to write to by our render pass
+		VkSubmitInfo submitInfo = {};
 		submitInfo.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
 		submitInfo.commandBufferCount = 1;
-		submitInfo.pCommandBuffers = &postPresentCmdBuffer;
+		submitInfo.pCommandBuffers = &postPresentCmdBuffers[currentBuffer];
 
 		VK_CHECK_RESULT(vkQueueSubmit(queue, 1, &submitInfo, VK_NULL_HANDLE));
 		
@@ -347,7 +354,6 @@ public:
 		// command buffers and semaphores to be submitted to a queue
 		// If you want to submit multiple command buffers, pass an array
 		VkPipelineStageFlags pipelineStages = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
-		VkSubmitInfo submitInfo = {};
 		submitInfo.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
 		submitInfo.pWaitDstStageMask = &pipelineStages;
 		// The wait semaphore ensures that the image is presented