Month 2 - Part 1

Over the past week I was working on a Vulkan validation error that was caused by some weird environment setup on my machine. The error was complaining about not knowing what a specific struct type was when chaining features on in our CreateVkDevice() method in this section of the code:

What was happening was the requested API got set to 1.3 but 1.4 was defined so when it would hit the #if defined(VK_API_VERSION_1_4) it would try to chain on the 1.4 feature struct but was using the 1.3 validation layers which were too old to recognize this newer struct.

Validation layers in Vulkan are meant as a debug tool to tell you when your pipeline/set up is off and helps debug issues early before they become a problem in release. Despite the message, everything got set up correctly and I couldn't reproduce the issue reliably so Lari and I decided that it would be best to move on as it was probably a user error in how I set up the project and my environment variables.

I then moved on to an issue reported to us by Justin Edwards:
VUID-VkDeviceCreateInfo-pNext-02830(ERROR / SPEC): msgNum: 555635515 - Validation Error: [ VUID-VkDeviceCreateInfo-pNext-02830 ] Object 0: handle = 0x25a8407cc70, type = VK_OBJECT_TYPE_INSTANCE; | MessageID = 0x211e533b | vkCreateDevice(): If the pNext chain includes a VkPhysicalDeviceVulkan12Features structure, then it must not include a VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_FEATURES structure

Which is complaining about 12 including the VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_FEATURES structure which comes from this part in our code:

Where before we didn't have the:

#if defined(VK_API_VERSION_1_2)

features12.descriptorIndexing = VK_TRUE;

#else

but with the new if define we're basically saying if we're on 1.2 or higher then we don't want to add that flag which ended up fixing the issue.

To ensure this fix was working we asked Justin for his exact setup and I created a test case mimicking this which looks like:

Which also accounts for the other versions of Vulkan. This test reproduced his errors without the fix and didn't produce them with it which proved our fix was working. He then downloaded the new Gateware version and tested it, confirming that it cleared that error but still produced this:

I'll be looking into what's causing this validation error along with tackling these tasks:

Which should provide some good learning opportunities for me.