Properly clean up semaphore from vkAcquireNextImage

src/HelloTriangle.cpp

@@ -233,6 +233,8 @@ void recordDraw( VkCommandBuffer commandBuffer, uint32_t vertexCount );
 void submitToQueue( VkQueue queue, VkCommandBuffer commandBuffer, VkSemaphore imageReadyS, VkSemaphore renderDoneS, VkFence fence = VK_NULL_HANDLE );
 void present( VkQueue queue, VkSwapchainKHR swapchain, uint32_t swapchainImageIndex, VkSemaphore renderDoneS );
 
+// cleanup dangerous semaphore with signal pending from vkAcquireNextImageKHR
+void cleanupUnsafeSemaphore( VkQueue queue, VkSemaphore semaphore );
 
 
 // main()!
@@ -416,7 +418,6 @@ int helloTriangle() try{
  killFences( device, submissionFences );
 
  // semaphores might be in signaled state, so kill them too to get fresh unsignaled
- TODO( "Unfortunately vkDeviceQueueIdle does not cover vkAcquireNextImage. This needs extra cleanup." )
  killSemaphores( device, renderDoneSs );
  killSemaphores( device, imageReadySs );
 
@@ -484,13 +485,19 @@ int helloTriangle() try{
  const std::function<void(void)> render = [&](){
  assert( swapchain ); // should be always true; should have yielded CPU if false
 
+ // vkAcquireNextImageKHR produces unsafe semaphore that needs extra cleanup. Track that with this variable.
+ bool unsafeSemaphore = false;
+
  try{
  // remove oldest frame from being in flight before starting new one
  // refer to doc/, which talks about the cycle of how the synch primitives are (re)used here
  {VkResult errorCode = vkWaitForFences( device, 1, &submissionFences[submissionNr], VK_TRUE, UINT64_MAX ); RESULT_HANDLER( errorCode, "vkWaitForFences" );}
  {VkResult errorCode = vkResetFences( device, 1, &submissionFences[submissionNr] ); RESULT_HANDLER( errorCode, "vkResetFences" );}
 
+ unsafeSemaphore = true;
  uint32_t nextSwapchainImageIndex = getNextImageIndex( device, swapchain, imageReadySs[submissionNr] );
+ unsafeSemaphore = false;
+
  if( presentQueueFamily != graphicsQueueFamily ) vkQueueWaitIdle( presentQueue ); // in the obscure case of separate present queue, make sure the renderDoneS can be reused; not really worried about perf for this obscure case
  submitToQueue( graphicsQueue, commandBuffers[nextSwapchainImageIndex], imageReadySs[submissionNr], renderDoneSs[submissionNr], submissionFences[submissionNr] );
  present( presentQueue, swapchain, nextSwapchainImageIndex, renderDoneSs[submissionNr] );
@@ -499,6 +506,9 @@ int helloTriangle() try{
  }
  catch( VulkanResultException ex ){
  if( ex.result == VK_SUBOPTIMAL_KHR || ex.result == VK_ERROR_OUT_OF_DATE_KHR ){
+ if( unsafeSemaphore && ex.result == VK_SUBOPTIMAL_KHR ){
+ cleanupUnsafeSemaphore( graphicsQueue, imageReadySs[submissionNr] );
+ }
  recreateSwapchain();
 
  // we need to start over...
@@ -1854,34 +1864,45 @@ void recordDraw( VkCommandBuffer commandBuffer, const uint32_t vertexCount ){
 }
 
 void submitToQueue( VkQueue queue, VkCommandBuffer commandBuffer, VkSemaphore imageReadyS, VkSemaphore renderDoneS, VkFence fence ){
- VkPipelineStageFlags psw = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
+ const VkPipelineStageFlags psw = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
 
- VkSubmitInfo submit{
+ const VkSubmitInfo submit{
  VK_STRUCTURE_TYPE_SUBMIT_INFO,
  nullptr, // pNext
- 1, // wait semaphore count
- &imageReadyS, // semaphores
+ 1, &imageReadyS, // wait semaphores
  &psw, // pipeline stages to wait for semaphore
- 1,
- &commandBuffer,
- 1, // signal semaphore count
- &renderDoneS // signal semaphores
+ 1, &commandBuffer,
+ 1, &renderDoneS // signal semaphores
  };
 
- VkResult errorCode = vkQueueSubmit( queue, 1 /*submit count*/, &submit, fence ); RESULT_HANDLER( errorCode, "vkQueueSubmit" );
+ const VkResult errorCode = vkQueueSubmit( queue, 1 /*submit count*/, &submit, fence ); RESULT_HANDLER( errorCode, "vkQueueSubmit" );
 }
 
 void present( VkQueue queue, VkSwapchainKHR swapchain, uint32_t swapchainImageIndex, VkSemaphore renderDoneS ){
- VkPresentInfoKHR presentInfo{
+ const VkPresentInfoKHR presentInfo{
  VK_STRUCTURE_TYPE_PRESENT_INFO_KHR,
  nullptr, // pNext
- 1, // wait semaphore count
- &renderDoneS, // wait semaphores
- 1, // swapchain count
- &swapchain,
- &swapchainImageIndex,
+ 1, &renderDoneS, // wait semaphores
+ 1, &swapchain, &swapchainImageIndex,
  nullptr // pResults
  };
 
- VkResult errorCode = vkQueuePresentKHR( queue, &presentInfo ); RESULT_HANDLER( errorCode, "vkQueuePresentKHR" );
+ const VkResult errorCode = vkQueuePresentKHR( queue, &presentInfo ); RESULT_HANDLER( errorCode, "vkQueuePresentKHR" );
+}
+
+// cleanup dangerous semaphore with signal pending from vkAcquireNextImageKHR (tie it to a specific queue)
+// https://github.com/KhronosGroup/Vulkan-Docs/issues/152
+void cleanupUnsafeSemaphore( VkQueue queue, VkSemaphore semaphore ){
+ VkPipelineStageFlags psw = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
+
+ const VkSubmitInfo submit{
+ VK_STRUCTURE_TYPE_SUBMIT_INFO,
+ nullptr, // pNext
+ 1, &semaphore, // wait semaphores
+ &psw, // pipeline stages to wait for semaphore
+ 0, nullptr, // command buffers
+ 0, nullptr // signal semaphores
+ };
+
+ const VkResult errorCode = vkQueueSubmit( queue, 1 /*submit count*/, &submit, VK_NULL_HANDLE ); RESULT_HANDLER( errorCode, "vkQueueSubmit" );
 }