IntroductionToVulkan | Source code examples for `` API without Secrets | Learning library

VK_ERROR_VALIDATION_FAILED_EXT is often returned in the case when you return VK_TRUE from your debug callback. The specification advises against doing that:

The callback returns a VkBool32 that indicates to the calling layer the application’s desire to abort the call. A value of VK_TRUE indicates that the application wants to abort this call. If the application returns VK_FALSE, the command must not be aborted. Applications should always return VK_FALSE so that they see the same behavior with and without validation layers enabled.

The value VK_TRUE is intended only for the purposes of layer development. Its current use is for unit testing of the layers, which requires the command to be aborted before it reaches the GPU driver (to prevent crashes the test is not interested in). It is common mistake to use it in applications. As the quote says applications are supposed to always use VK_FALSE.

In your case the layer is behaving bit oddly, but what probably happened is:

1. Both your app and the tutorial produce a benign warning on vkCmdPipelineBarrier.
2. Because you return VK_TRUE the barrier is aborted and does not count.
3. vkCmdPipelineBarrier returns void (i.e. cannot return VK_ERROR_VALIDATION_FAILED_EXT) so you never learned it was actually aborted.
4. Because the layout transition was aborted you have image in wrong layout on vkQueueSubmit and so you get an appropriate error.