Vulkan conformance tests for graphics drivers save their output images inside an XML file called TestResults.qpa. As binary outputs aren’t allowed, these output images (that would be saved as PNG otherwise) are encoded to text using Base64 and the result is printed between <Image></Image> XML tags. This is a problem sometimes, as external tools are required to display them. In this post I’d like to share a few simple hacks I’m using to instantly display the CTS output image when I’m running a CTS test, hoping that they might be handy to more people who work on the drivers.
Vkrunner is a Vulkan shader testing tool similar to Piglit, written by Neil Roberts. It is mostly used by graphics drivers developers, and was also part of the official Khronosconformance tests suite repository (VK-GL-CTS) for some time . There are already posts  about its use but they are all written from a driver developer’s perspective and focus on vkrunner’s debugging capabilities. In this post, I’m going to show you an alternative use I’ve found for it, in order to have fun with pixel shaders during my holidays! 🙂
The video mostly shows the behavior of some GL calls and operations with and without the patches that improve the emulation of the ETC/EAC formats on Gen7 GPUs. The same programs run first with the previous ETC/EAC emulation (upper terminal) and then with the new one (lower terminal).