Fix queue family transfer operations between graphics <-> compute queues, generalize getQueueFamilyIndex() to support VkQueueFlags vs. VkQueueFlagBits, computecloth deltaT now based on frameTimer

base/VulkanDevice.cpp

@@ -120,6 +120,7 @@ namespace vks
 
 	/**
 	* Get the index of a queue family that supports the requested queue flags
+	* SRS - support VkQueueFlags parameter for requesting multiple flags vs. VkQueueFlagBits for a single flag only
 	*
 	* @param queueFlags Queue flags to find a queue family index for
 	*
@@ -127,15 +128,15 @@ namespace vks
 	*
 	* @throw Throws an exception if no queue family index could be found that supports the requested flags
 	*/
-	uint32_t VulkanDevice::getQueueFamilyIndex(VkQueueFlagBits queueFlags) const
+	uint32_t VulkanDevice::getQueueFamilyIndex(VkQueueFlags queueFlags) const
 	{
 		// Dedicated queue for compute
 		// Try to find a queue family index that supports compute but not graphics
-		if (queueFlags & VK_QUEUE_COMPUTE_BIT)
+		if ((queueFlags & VK_QUEUE_COMPUTE_BIT) == queueFlags)
 		{
 			for (uint32_t i = 0; i < static_cast<uint32_t>(queueFamilyProperties.size()); i++)
 			{
-				if ((queueFamilyProperties[i].queueFlags & queueFlags) && ((queueFamilyProperties[i].queueFlags & VK_QUEUE_GRAPHICS_BIT) == 0))
+				if ((queueFamilyProperties[i].queueFlags & VK_QUEUE_COMPUTE_BIT) && ((queueFamilyProperties[i].queueFlags & VK_QUEUE_GRAPHICS_BIT) == 0))
 				{
 					return i;
 				}
@@ -144,11 +145,11 @@ namespace vks
 
 		// Dedicated queue for transfer
 		// Try to find a queue family index that supports transfer but not graphics and compute
-		if (queueFlags & VK_QUEUE_TRANSFER_BIT)
+		if ((queueFlags & VK_QUEUE_TRANSFER_BIT) == queueFlags)
 		{
 			for (uint32_t i = 0; i < static_cast<uint32_t>(queueFamilyProperties.size()); i++)
 			{
-				if ((queueFamilyProperties[i].queueFlags & queueFlags) && ((queueFamilyProperties[i].queueFlags & VK_QUEUE_GRAPHICS_BIT) == 0) && ((queueFamilyProperties[i].queueFlags & VK_QUEUE_COMPUTE_BIT) == 0))
+				if ((queueFamilyProperties[i].queueFlags & VK_QUEUE_TRANSFER_BIT) && ((queueFamilyProperties[i].queueFlags & VK_QUEUE_GRAPHICS_BIT) == 0) && ((queueFamilyProperties[i].queueFlags & VK_QUEUE_COMPUTE_BIT) == 0))
 				{
 					return i;
 				}
@@ -158,7 +159,7 @@ namespace vks
 		// For other queue types or if no separate compute queue is present, return the first one to support the requested flags
 		for (uint32_t i = 0; i < static_cast<uint32_t>(queueFamilyProperties.size()); i++)
 		{
-			if (queueFamilyProperties[i].queueFlags & queueFlags)
+			if ((queueFamilyProperties[i].queueFlags & queueFlags) == queueFlags)
 			{
 				return i;
 			}
@@ -233,7 +234,7 @@ namespace vks
 			queueFamilyIndices.transfer = getQueueFamilyIndex(VK_QUEUE_TRANSFER_BIT);
 			if ((queueFamilyIndices.transfer != queueFamilyIndices.graphics) && (queueFamilyIndices.transfer != queueFamilyIndices.compute))
 			{
-				// If compute family index differs, we need an additional queue create info for the compute queue
+				// If transfer family index differs, we need an additional queue create info for the transfer queue
 				VkDeviceQueueCreateInfo queueInfo{};
 				queueInfo.sType = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO;
 				queueInfo.queueFamilyIndex = queueFamilyIndices.transfer;

base/VulkanDevice.h

@@ -55,7 +55,7 @@ struct VulkanDevice
 	explicit VulkanDevice(VkPhysicalDevice physicalDevice);
 	~VulkanDevice();
 	uint32_t        getMemoryType(uint32_t typeBits, VkMemoryPropertyFlags properties, VkBool32 *memTypeFound = nullptr) const;
-	uint32_t        getQueueFamilyIndex(VkQueueFlagBits queueFlags) const;
+	uint32_t        getQueueFamilyIndex(VkQueueFlags queueFlags) const;
 	VkResult        createLogicalDevice(VkPhysicalDeviceFeatures enabledFeatures, std::vector<const char *> enabledExtensions, void *pNextChain, bool useSwapChain = true, VkQueueFlags requestedQueueTypes = VK_QUEUE_GRAPHICS_BIT | VK_QUEUE_COMPUTE_BIT);
 	VkResult        createBuffer(VkBufferUsageFlags usageFlags, VkMemoryPropertyFlags memoryPropertyFlags, VkDeviceSize size, VkBuffer *buffer, VkDeviceMemory *memory, void *data = nullptr);
 	VkResult        createBuffer(VkBufferUsageFlags usageFlags, VkMemoryPropertyFlags memoryPropertyFlags, vks::Buffer *buffer, VkDeviceSize size, void *data = nullptr);

examples/computecloth/computecloth.cpp

@@ -136,12 +136,12 @@ public:
 		textureCloth.loadFromFile(getAssetPath() + "textures/vulkan_cloth_rgba.ktx", VK_FORMAT_R8G8B8A8_UNORM, vulkanDevice, queue);
 	}
 
-	void addGraphicsToComputeBarriers(VkCommandBuffer commandBuffer)
+	void addGraphicsToComputeBarriers(VkCommandBuffer commandBuffer, VkAccessFlags srcAccessMask, VkAccessFlags dstAccessMask, VkPipelineStageFlags srcStageMask, VkPipelineStageFlags dstStageMask)
 	{
 		if (specializedComputeQueue) {
 			VkBufferMemoryBarrier bufferBarrier = vks::initializers::bufferMemoryBarrier();
-			bufferBarrier.srcAccessMask = VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT;
+			bufferBarrier.srcAccessMask = srcAccessMask;
-			bufferBarrier.dstAccessMask = VK_ACCESS_SHADER_WRITE_BIT;
+			bufferBarrier.dstAccessMask = dstAccessMask;
 			bufferBarrier.srcQueueFamilyIndex = vulkanDevice->queueFamilyIndices.graphics;
 			bufferBarrier.dstQueueFamilyIndex = vulkanDevice->queueFamilyIndices.compute;
 			bufferBarrier.size = VK_WHOLE_SIZE;
@@ -152,8 +152,8 @@ public:
 			bufferBarrier.buffer = compute.storageBuffers.output.buffer;
 			bufferBarriers.push_back(bufferBarrier);
 			vkCmdPipelineBarrier(commandBuffer,
-				VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
+				srcStageMask,
-				VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
+				dstStageMask,
 				VK_FLAGS_NONE,
 				0, nullptr,
 				static_cast<uint32_t>(bufferBarriers.size()), bufferBarriers.data(),
@@ -166,8 +166,8 @@ public:
 		VkBufferMemoryBarrier bufferBarrier = vks::initializers::bufferMemoryBarrier();
 		bufferBarrier.srcAccessMask = VK_ACCESS_SHADER_WRITE_BIT;
 		bufferBarrier.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
-		bufferBarrier.srcQueueFamilyIndex = vulkanDevice->queueFamilyIndices.compute;
+		bufferBarrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
-		bufferBarrier.dstQueueFamilyIndex = vulkanDevice->queueFamilyIndices.compute;
+		bufferBarrier.dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
 		bufferBarrier.size = VK_WHOLE_SIZE;
 		std::vector<VkBufferMemoryBarrier> bufferBarriers;
 		bufferBarrier.buffer = compute.storageBuffers.input.buffer;
@@ -184,12 +184,12 @@ public:
 			0, nullptr);
 	}
 
-	void addComputeToGraphicsBarriers(VkCommandBuffer commandBuffer)
+	void addComputeToGraphicsBarriers(VkCommandBuffer commandBuffer, VkAccessFlags srcAccessMask, VkAccessFlags dstAccessMask, VkPipelineStageFlags srcStageMask, VkPipelineStageFlags dstStageMask)
 	{
 		if (specializedComputeQueue) {
 			VkBufferMemoryBarrier bufferBarrier = vks::initializers::bufferMemoryBarrier();
-			bufferBarrier.srcAccessMask = VK_ACCESS_SHADER_WRITE_BIT;
+			bufferBarrier.srcAccessMask = srcAccessMask;
-			bufferBarrier.dstAccessMask = VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT;
+			bufferBarrier.dstAccessMask = dstAccessMask;
 			bufferBarrier.srcQueueFamilyIndex = vulkanDevice->queueFamilyIndices.compute;
 			bufferBarrier.dstQueueFamilyIndex = vulkanDevice->queueFamilyIndices.graphics;
 			bufferBarrier.size = VK_WHOLE_SIZE;
@@ -200,8 +200,8 @@ public:
 			bufferBarriers.push_back(bufferBarrier);
 			vkCmdPipelineBarrier(
 				commandBuffer,
-				VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
+				srcStageMask,
-				VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
+				dstStageMask,
 				VK_FLAGS_NONE,
 				0, nullptr,
 				static_cast<uint32_t>(bufferBarriers.size()), bufferBarriers.data(),
@@ -234,7 +234,7 @@ public:
 			VK_CHECK_RESULT(vkBeginCommandBuffer(drawCmdBuffers[i], &cmdBufInfo));
 
 			// Acquire storage buffers from compute queue
-			addComputeToGraphicsBarriers(drawCmdBuffers[i]);
+			addComputeToGraphicsBarriers(drawCmdBuffers[i], 0, VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT, VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT, VK_PIPELINE_STAGE_VERTEX_INPUT_BIT);
 
 			// Draw the particle system using the update vertex buffer
 
@@ -267,7 +267,7 @@ public:
 			vkCmdEndRenderPass(drawCmdBuffers[i]);
 
 			// release the storage buffers to the compute queue
-			addGraphicsToComputeBarriers(drawCmdBuffers[i]);
+			addGraphicsToComputeBarriers(drawCmdBuffers[i], VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT, 0, VK_PIPELINE_STAGE_VERTEX_INPUT_BIT, VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT);
 
 			VK_CHECK_RESULT(vkEndCommandBuffer(drawCmdBuffers[i]));
 		}
@@ -285,7 +285,7 @@ public:
 			VK_CHECK_RESULT(vkBeginCommandBuffer(compute.commandBuffers[i], &cmdBufInfo));
 
 			// Acquire the storage buffers from the graphics queue
-			addGraphicsToComputeBarriers(compute.commandBuffers[i]);
+			addGraphicsToComputeBarriers(compute.commandBuffers[i], 0, VK_ACCESS_SHADER_WRITE_BIT, VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT, VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT);
 
 			vkCmdBindPipeline(compute.commandBuffers[i], VK_PIPELINE_BIND_POINT_COMPUTE, compute.pipeline);
 
@@ -313,7 +313,7 @@ public:
 			}
 
 			// release the storage buffers back to the graphics queue
-			addComputeToGraphicsBarriers(compute.commandBuffers[i]);
+			addComputeToGraphicsBarriers(compute.commandBuffers[i], VK_ACCESS_SHADER_WRITE_BIT, 0, VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT, VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT);
 			vkEndCommandBuffer(compute.commandBuffers[i]);
 		}
 	}
@@ -396,7 +396,7 @@ public:
 		// Add an initial release barrier to the graphics queue,
 		// so that when the compute command buffer executes for the first time
 		// it doesn't complain about a lack of a corresponding "release" to its "acquire"
-		addGraphicsToComputeBarriers(copyCmd);
+		addGraphicsToComputeBarriers(copyCmd, VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT, 0, VK_PIPELINE_STAGE_VERTEX_INPUT_BIT, VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT);
 		vulkanDevice->flushCommandBuffer(copyCmd, queue, true);
 
 		stagingBuffer.destroy();
@@ -673,11 +673,12 @@ public:
 		if (!paused) {
 			//compute.ubo.deltaT = 0.000005f;
 			// todo: base on frametime
-			compute.ubo.deltaT = frameTimer * 0.0015f;
+			// SRS - Clamp frameTimer to max 20ms refresh period (e.g. if blocked on resize), otherwise image breakup can occur
+			compute.ubo.deltaT = fmin(frameTimer, 0.02) * 0.0025f;
 
 			if (simulateWind) {
 				std::default_random_engine rndEngine(benchmark.active ? 0 : (unsigned)time(nullptr));
-				std::uniform_real_distribution<float> rd(1.0f, 30.0f);
+				std::uniform_real_distribution<float> rd(1.0f, 12.0f);
 				compute.ubo.gravity.x = cos(glm::radians(-timer * 360.0f)) * (rd(rndEngine) - rd(rndEngine));
 				compute.ubo.gravity.z = sin(glm::radians(timer * 360.0f)) * (rd(rndEngine) - rd(rndEngine));
 			}

examples/computecullandlod/computecullandlod.cpp

@@ -149,6 +149,32 @@ public:
 
 			VK_CHECK_RESULT(vkBeginCommandBuffer(drawCmdBuffers[i], &cmdBufInfo));
 
+			// Acquire barrier
+			if (vulkanDevice->queueFamilyIndices.graphics != vulkanDevice->queueFamilyIndices.compute)
+			{
+				VkBufferMemoryBarrier buffer_barrier =
+				{
+					VK_STRUCTURE_TYPE_BUFFER_MEMORY_BARRIER,
+					nullptr,
+					0,
+					VK_ACCESS_INDIRECT_COMMAND_READ_BIT,
+					vulkanDevice->queueFamilyIndices.compute,
+					vulkanDevice->queueFamilyIndices.graphics,
+					indirectCommandsBuffer.buffer,
+					0,
+					indirectCommandsBuffer.descriptor.range
+				};
+
+				vkCmdPipelineBarrier(
+					drawCmdBuffers[i],
+					VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT,
+					VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT,
+					0,
+					0, nullptr,
+					1, &buffer_barrier,
+					0, nullptr);
+			}
+
 			vkCmdBeginRenderPass(drawCmdBuffers[i], &renderPassBeginInfo, VK_SUBPASS_CONTENTS_INLINE);
 
 			VkViewport viewport = vks::initializers::viewport((float)width, (float)height, 0.0f, 1.0f);
@@ -169,7 +195,7 @@ public:
 
 			if (vulkanDevice->features.multiDrawIndirect)
 			{
-				vkCmdDrawIndexedIndirect(drawCmdBuffers[i], indirectCommandsBuffer.buffer, 0, indirectCommands.size(), sizeof(VkDrawIndexedIndirectCommand));
+				vkCmdDrawIndexedIndirect(drawCmdBuffers[i], indirectCommandsBuffer.buffer, 0, static_cast<uint32_t>(indirectCommands.size()), sizeof(VkDrawIndexedIndirectCommand));
 			}
 			else
 			{
@@ -184,6 +210,32 @@ public:
 
 			vkCmdEndRenderPass(drawCmdBuffers[i]);
 
+			// Release barrier
+			if (vulkanDevice->queueFamilyIndices.graphics != vulkanDevice->queueFamilyIndices.compute)
+			{
+				VkBufferMemoryBarrier buffer_barrier =
+				{
+					VK_STRUCTURE_TYPE_BUFFER_MEMORY_BARRIER,
+					nullptr,
+					VK_ACCESS_INDIRECT_COMMAND_READ_BIT,
+					0,
+					vulkanDevice->queueFamilyIndices.graphics,
+					vulkanDevice->queueFamilyIndices.compute,
+					indirectCommandsBuffer.buffer,
+					0,
+					indirectCommandsBuffer.descriptor.range
+				};
+
+				vkCmdPipelineBarrier(
+					drawCmdBuffers[i],
+					VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT,
+					VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
+					0,
+					0, nullptr,
+					1, &buffer_barrier,
+					0, nullptr);
+			}
+
 			VK_CHECK_RESULT(vkEndCommandBuffer(drawCmdBuffers[i]));
 		}
 	}
@@ -200,23 +252,32 @@ public:
 
 		VK_CHECK_RESULT(vkBeginCommandBuffer(compute.commandBuffer, &cmdBufInfo));
 
+		// Acquire barrier
 		// Add memory barrier to ensure that the indirect commands have been consumed before the compute shader updates them
-		VkBufferMemoryBarrier bufferBarrier = vks::initializers::bufferMemoryBarrier();
+		if (vulkanDevice->queueFamilyIndices.graphics != vulkanDevice->queueFamilyIndices.compute)
-		bufferBarrier.buffer = indirectCommandsBuffer.buffer;
+		{
-		bufferBarrier.size = indirectCommandsBuffer.descriptor.range;
+			VkBufferMemoryBarrier buffer_barrier =
-		bufferBarrier.srcAccessMask = VK_ACCESS_INDIRECT_COMMAND_READ_BIT;
+			{
-		bufferBarrier.dstAccessMask = VK_ACCESS_SHADER_WRITE_BIT;
+				VK_STRUCTURE_TYPE_BUFFER_MEMORY_BARRIER,
-		bufferBarrier.srcQueueFamilyIndex = vulkanDevice->queueFamilyIndices.graphics;
+				nullptr,
-		bufferBarrier.dstQueueFamilyIndex = vulkanDevice->queueFamilyIndices.compute;
+				0,
+				VK_ACCESS_SHADER_WRITE_BIT,
+				vulkanDevice->queueFamilyIndices.graphics,
+				vulkanDevice->queueFamilyIndices.compute,
+				indirectCommandsBuffer.buffer,
+				0,
+				indirectCommandsBuffer.descriptor.range
+			};
 
 			vkCmdPipelineBarrier(
 				compute.commandBuffer,
-			VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT,
+				VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT,
 				VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
 				VK_FLAGS_NONE,
 				0, nullptr,
-			1, &bufferBarrier,
+				1, &buffer_barrier,
 				0, nullptr);
+		}
 
 		vkCmdBindPipeline(compute.commandBuffer, VK_PIPELINE_BIND_POINT_COMPUTE, compute.pipeline);
 		vkCmdBindDescriptorSets(compute.commandBuffer, VK_PIPELINE_BIND_POINT_COMPUTE, compute.pipelineLayout, 0, 1, &compute.descriptorSet, 0, 0);
@@ -226,22 +287,32 @@ public:
 		// It also determines the lod to use depending on distance to the viewer.
 		vkCmdDispatch(compute.commandBuffer, objectCount / 16, 1, 1);
 
+		// Release barrier
 		// Add memory barrier to ensure that the compute shader has finished writing the indirect command buffer before it's consumed
-		bufferBarrier.srcAccessMask = VK_ACCESS_SHADER_WRITE_BIT;
+		if (vulkanDevice->queueFamilyIndices.graphics != vulkanDevice->queueFamilyIndices.compute)
-		bufferBarrier.dstAccessMask = VK_ACCESS_INDIRECT_COMMAND_READ_BIT;
+		{
-		bufferBarrier.buffer = indirectCommandsBuffer.buffer;
+			VkBufferMemoryBarrier buffer_barrier =
-		bufferBarrier.size = indirectCommandsBuffer.descriptor.range;
+			{
-		bufferBarrier.srcQueueFamilyIndex = vulkanDevice->queueFamilyIndices.compute;
+				VK_STRUCTURE_TYPE_BUFFER_MEMORY_BARRIER,
-		bufferBarrier.dstQueueFamilyIndex = vulkanDevice->queueFamilyIndices.graphics;
+				nullptr,
+				VK_ACCESS_SHADER_WRITE_BIT,
+				0,
+				vulkanDevice->queueFamilyIndices.compute,
+				vulkanDevice->queueFamilyIndices.graphics,
+				indirectCommandsBuffer.buffer,
+				0,
+				indirectCommandsBuffer.descriptor.range
+			};
 
 			vkCmdPipelineBarrier(
 				compute.commandBuffer,
 				VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
-			VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT,
+				VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
 				VK_FLAGS_NONE,
 				0, nullptr,
-			1, &bufferBarrier,
+				1, &buffer_barrier,
 				0, nullptr);
+		}
 
 		// todo: barrier for indirect stats buffer?
 
@@ -424,7 +495,38 @@ public:
 			&instanceBuffer,
 			stagingBuffer.size));
 
-		vulkanDevice->copyBuffer(&stagingBuffer, &instanceBuffer, queue);
+		// Copy from staging buffer to instance buffer
+		VkCommandBuffer copyCmd = vulkanDevice->createCommandBuffer(VK_COMMAND_BUFFER_LEVEL_PRIMARY, true);
+		VkBufferCopy copyRegion = {};
+		copyRegion.size = stagingBuffer.size;
+		vkCmdCopyBuffer(copyCmd, stagingBuffer.buffer, instanceBuffer.buffer, 1, &copyRegion);
+		// Add an initial release barrier to the graphics queue,
+		// so that when the compute command buffer executes for the first time
+		// it doesn't complain about a lack of a corresponding "release" to its "acquire"
+		if (vulkanDevice->queueFamilyIndices.graphics != vulkanDevice->queueFamilyIndices.compute)
+		{			VkBufferMemoryBarrier buffer_barrier =
+			{
+				VK_STRUCTURE_TYPE_BUFFER_MEMORY_BARRIER,
+				nullptr,
+				VK_ACCESS_INDIRECT_COMMAND_READ_BIT,
+				0,
+				vulkanDevice->queueFamilyIndices.graphics,
+				vulkanDevice->queueFamilyIndices.compute,
+				indirectCommandsBuffer.buffer,
+				0,
+				indirectCommandsBuffer.descriptor.range
+			};
+
+			vkCmdPipelineBarrier(
+				copyCmd,
+				VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT,
+				VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
+				0,
+				0, nullptr,
+				1, &buffer_barrier,
+				0, nullptr);
+		}
+		vulkanDevice->flushCommandBuffer(copyCmd, queue, true);
 
 		stagingBuffer.destroy();
 
@@ -710,6 +812,11 @@ public:
 		}
 	}
 
+	virtual void viewChanged()
+	{
+		updateUniformBuffer(true);
+	}
+
 	virtual void OnUpdateUIOverlay(vks::UIOverlay *overlay)
 	{
 		if (overlay->header("Settings")) {

examples/computenbody/computenbody.cpp

@@ -160,7 +160,7 @@ public:
 
 				vkCmdPipelineBarrier(
 					drawCmdBuffers[i],
-					VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
+					VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT,
 					VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
 					0,
 					0, nullptr,
@@ -207,7 +207,7 @@ public:
 				vkCmdPipelineBarrier(
 					drawCmdBuffers[i],
 					VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
-					VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
+					VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
 					0,
 					0, nullptr,
 					1, &buffer_barrier,
@@ -243,7 +243,7 @@ public:
 
 			vkCmdPipelineBarrier(
 				compute.commandBuffer,
-				VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
+				VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT,
 				VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
 				0,
 				0, nullptr,
@@ -300,7 +300,7 @@ public:
 			vkCmdPipelineBarrier(
 				compute.commandBuffer,
 				VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
-				VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
+				VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
 				0,
 				0, nullptr,
 				1, &buffer_barrier,
@@ -417,7 +417,7 @@ public:
 			vkCmdPipelineBarrier(
 				copyCmd,
 				VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
-				VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
+				VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
 				0,
 				0, nullptr,
 				1, &buffer_barrier,
@@ -746,7 +746,9 @@ public:
 		// Build a single command buffer containing the compute dispatch commands
 		buildComputeCommandBuffer();
 
+		// SRS - By reordering compute and graphics within draw(), the following code is no longer needed:
 		// If graphics and compute queue family indices differ, acquire and immediately release the storage buffer, so that the initial acquire from the graphics command buffers are matched up properly
+		/*
 		if (graphics.queueFamilyIndex != compute.queueFamilyIndex)
 		{
 			// Create a transient command buffer for setting up the initial buffer transfer state
@@ -796,6 +798,7 @@ public:
 
 			vulkanDevice->flushCommandBuffer(transferCmd, compute.queue, compute.commandPool);
 		}
+		*/
 	}
 
 	// Prepare and initialize uniform buffer containing shader uniforms
@@ -899,6 +902,11 @@ public:
 			updateGraphicsUniformBuffers();
 		}
 	}
+
+	virtual void viewChanged()
+	{
+		updateGraphicsUniformBuffers();
+	}
 };
 
 VULKAN_EXAMPLE_MAIN()

examples/computeparticles/computeparticles.cpp

@@ -149,7 +149,7 @@ public:
 
 				vkCmdPipelineBarrier(
 					drawCmdBuffers[i],
-					VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
+					VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT,
 					VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
 					0,
 					0, nullptr,
@@ -196,7 +196,7 @@ public:
 				vkCmdPipelineBarrier(
 					drawCmdBuffers[i],
 					VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
-					VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
+					VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
 					0,
 					0, nullptr,
 					1, &buffer_barrier,
@@ -234,7 +234,7 @@ public:
 
 			vkCmdPipelineBarrier(
 				compute.commandBuffer,
-				VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
+				VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT,
 				VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
 				0,
 				0, nullptr,
@@ -267,7 +267,7 @@ public:
 			vkCmdPipelineBarrier(
 				compute.commandBuffer,
 				VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
-				VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
+				VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
 				0,
 				0, nullptr,
 				1, &buffer_barrier,
@@ -336,7 +336,7 @@ public:
 			vkCmdPipelineBarrier(
 				copyCmd,
 				VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,
-				VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
+				VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
 				0,
 				0, nullptr,
 				1, &buffer_barrier,
@@ -647,7 +647,9 @@ public:
 		// Build a single command buffer containing the compute dispatch commands
 		buildComputeCommandBuffer();
 
+		// SRS - By reordering compute and graphics within draw(), the following code is no longer needed:
 		// If graphics and compute queue family indices differ, acquire and immediately release the storage buffer, so that the initial acquire from the graphics command buffers are matched up properly
+		/*
 		if (graphics.queueFamilyIndex != compute.queueFamilyIndex)
 		{
 			// Create a transient command buffer for setting up the initial buffer transfer state
@@ -697,6 +699,7 @@ public:
 
 			vulkanDevice->flushCommandBuffer(transferCmd, compute.queue, compute.commandPool);
 		}
+		*/
 	}
 
 	// Prepare and initialize uniform buffer containing shader uniforms

examples/computeraytracing/computeraytracing.cpp

@@ -94,6 +94,9 @@ public:
 
 	~VulkanExample()
 	{
+		// SRS - Ensure all operations on the device have finished before destroying resources
+		vkDeviceWaitIdle(device);
+
 		// Graphics
 		vkDestroyPipeline(device, graphics.pipeline, nullptr);
 		vkDestroyPipelineLayout(device, graphics.pipelineLayout, nullptr);
@@ -223,8 +226,29 @@ public:
 			imageMemoryBarrier.newLayout = VK_IMAGE_LAYOUT_GENERAL;
 			imageMemoryBarrier.image = textureComputeTarget.image;
 			imageMemoryBarrier.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
+			if (vulkanDevice->queueFamilyIndices.graphics != vulkanDevice->queueFamilyIndices.compute)
+			{
+				// Acquire barrier for graphics queue
+				imageMemoryBarrier.srcAccessMask = 0;
+				imageMemoryBarrier.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
+				imageMemoryBarrier.srcQueueFamilyIndex = vulkanDevice->queueFamilyIndices.compute;
+				imageMemoryBarrier.dstQueueFamilyIndex = vulkanDevice->queueFamilyIndices.graphics;
+				vkCmdPipelineBarrier(
+					drawCmdBuffers[i],
+					VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT,
+					VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT,
+					VK_FLAGS_NONE,
+					0, nullptr,
+					0, nullptr,
+					1, &imageMemoryBarrier);
+			}
+			else
+			{
+				// Combined barrier on single queue family
 				imageMemoryBarrier.srcAccessMask = VK_ACCESS_SHADER_WRITE_BIT;
 				imageMemoryBarrier.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
+				imageMemoryBarrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
+				imageMemoryBarrier.dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
 				vkCmdPipelineBarrier(
 					drawCmdBuffers[i],
 					VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
@@ -233,6 +257,7 @@ public:
 					0, nullptr,
 					0, nullptr,
 					1, &imageMemoryBarrier);
+			}
 
 			vkCmdBeginRenderPass(drawCmdBuffers[i], &renderPassBeginInfo, VK_SUBPASS_CONTENTS_INLINE);
 
@@ -252,6 +277,23 @@ public:
 
 			vkCmdEndRenderPass(drawCmdBuffers[i]);
 
+			if (vulkanDevice->queueFamilyIndices.graphics != vulkanDevice->queueFamilyIndices.compute)
+			{
+				// Release barrier from graphics queue
+				imageMemoryBarrier.srcAccessMask = VK_ACCESS_SHADER_WRITE_BIT;
+				imageMemoryBarrier.dstAccessMask = 0;
+				imageMemoryBarrier.srcQueueFamilyIndex = vulkanDevice->queueFamilyIndices.graphics;
+				imageMemoryBarrier.dstQueueFamilyIndex = vulkanDevice->queueFamilyIndices.compute;
+				vkCmdPipelineBarrier(
+					drawCmdBuffers[i],
+					VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT,
+					VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
+					VK_FLAGS_NONE,
+					0, nullptr,
+					0, nullptr,
+					1, &imageMemoryBarrier);
+			}
+			
 			VK_CHECK_RESULT(vkEndCommandBuffer(drawCmdBuffers[i]));
 		}
 
@@ -263,11 +305,51 @@ public:
 
 		VK_CHECK_RESULT(vkBeginCommandBuffer(compute.commandBuffer, &cmdBufInfo));
 		
+		VkImageMemoryBarrier imageMemoryBarrier = {};
+		imageMemoryBarrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
+		imageMemoryBarrier.oldLayout = VK_IMAGE_LAYOUT_GENERAL;
+		imageMemoryBarrier.newLayout = VK_IMAGE_LAYOUT_GENERAL;
+		imageMemoryBarrier.image = textureComputeTarget.image;
+		imageMemoryBarrier.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
+		if (vulkanDevice->queueFamilyIndices.graphics != vulkanDevice->queueFamilyIndices.compute)
+		{
+			// Acquire barrier for compute queue
+			imageMemoryBarrier.srcAccessMask = 0;
+			imageMemoryBarrier.dstAccessMask = VK_ACCESS_SHADER_WRITE_BIT;
+			imageMemoryBarrier.srcQueueFamilyIndex = vulkanDevice->queueFamilyIndices.graphics;
+			imageMemoryBarrier.dstQueueFamilyIndex = vulkanDevice->queueFamilyIndices.compute;
+			vkCmdPipelineBarrier(
+				compute.commandBuffer,
+				VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT,
+				VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
+				VK_FLAGS_NONE,
+				0, nullptr,
+				0, nullptr,
+				1, &imageMemoryBarrier);
+		}
+
 		vkCmdBindPipeline(compute.commandBuffer, VK_PIPELINE_BIND_POINT_COMPUTE, compute.pipeline);
 		vkCmdBindDescriptorSets(compute.commandBuffer, VK_PIPELINE_BIND_POINT_COMPUTE, compute.pipelineLayout, 0, 1, &compute.descriptorSet, 0, 0);
 
 		vkCmdDispatch(compute.commandBuffer, textureComputeTarget.width / 16, textureComputeTarget.height / 16, 1);
 
+		if (vulkanDevice->queueFamilyIndices.graphics != vulkanDevice->queueFamilyIndices.compute)
+		{
+			// Release barrier from compute queue
+			imageMemoryBarrier.srcAccessMask = VK_ACCESS_SHADER_WRITE_BIT;
+			imageMemoryBarrier.dstAccessMask = 0;
+			imageMemoryBarrier.srcQueueFamilyIndex = vulkanDevice->queueFamilyIndices.compute;
+			imageMemoryBarrier.dstQueueFamilyIndex = vulkanDevice->queueFamilyIndices.graphics;
+			vkCmdPipelineBarrier(
+				compute.commandBuffer,
+				VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT,
+				VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
+				VK_FLAGS_NONE,
+				0, nullptr,
+				0, nullptr,
+				1, &imageMemoryBarrier);
+		}
+
 		vkEndCommandBuffer(compute.commandBuffer);
 	}
 
@@ -361,6 +443,30 @@ public:
 		copyCmd = vulkanDevice->createCommandBuffer(VK_COMMAND_BUFFER_LEVEL_PRIMARY, true);
 		copyRegion.size = storageBufferSize;
 		vkCmdCopyBuffer(copyCmd, stagingBuffer.buffer, compute.storageBuffers.planes.buffer, 1, &copyRegion);
+		// Add an initial release barrier to the graphics queue,
+		// so that when the compute command buffer executes for the first time
+		// it doesn't complain about a lack of a corresponding "release" to its "acquire"
+		if (vulkanDevice->queueFamilyIndices.graphics != vulkanDevice->queueFamilyIndices.compute)
+		{
+			VkImageMemoryBarrier imageMemoryBarrier = {};
+			imageMemoryBarrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
+			imageMemoryBarrier.oldLayout = VK_IMAGE_LAYOUT_GENERAL;
+			imageMemoryBarrier.newLayout = VK_IMAGE_LAYOUT_GENERAL;
+			imageMemoryBarrier.image = textureComputeTarget.image;
+			imageMemoryBarrier.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
+			imageMemoryBarrier.srcAccessMask = VK_ACCESS_SHADER_WRITE_BIT;
+			imageMemoryBarrier.dstAccessMask = 0;
+			imageMemoryBarrier.srcQueueFamilyIndex = vulkanDevice->queueFamilyIndices.graphics;
+			imageMemoryBarrier.dstQueueFamilyIndex = vulkanDevice->queueFamilyIndices.compute;
+			vkCmdPipelineBarrier(
+				copyCmd,
+				VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT,
+				VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
+				VK_FLAGS_NONE,
+				0, nullptr,
+				0, nullptr,
+				1, &imageMemoryBarrier);
+		}
 		vulkanDevice->flushCommandBuffer(copyCmd, queue, true);
 
 		stagingBuffer.destroy();
@@ -689,9 +795,9 @@ public:
 	void prepare()
 	{
 		VulkanExampleBase::prepare();
+		prepareTextureTarget(&textureComputeTarget, TEX_DIM, TEX_DIM, VK_FORMAT_R8G8B8A8_UNORM);
 		prepareStorageBuffers();
 		prepareUniformBuffers();
-		prepareTextureTarget(&textureComputeTarget, TEX_DIM, TEX_DIM, VK_FORMAT_R8G8B8A8_UNORM);
 		setupDescriptorSetLayout();
 		preparePipelines();
 		setupDescriptorPool();