Mesa NVK Vulkan Driver Adds VK_KHR_fragment_shading_rate Support

Adding to the growing set of features for NVK as this open-source NVIDIA Vulkan driver within Mesa, the VK_KHR_fragment_shading_rate fragment shading rate extension is now supported.

VK_KHR_fragment_shading_rate was introduced back in 2020 as to allow changing the rate at which fragments are shaded. Multiple pixels can be shaded now by a single fragment shader invocation. The new extension allows controlling the fragment shading rate on a per-draw, per-primitive, or per-region basis. Most notably this can be used by Vulkan-powered games for shading higher levels of detail in a scene compared to others. Or rather lower quality shading in some areas of the frame.

VK_KHR_fragment_shading_rate has been supported across all the prominent Vulkan drivers for quite a while now and is seeing support at long last for the NVK driver. Among use directly by Vulkan API rendered games and other software, VK_KHR_fragment_shading_rate is necessary for VKD3D-Proton support for exposing the Direct3D 12.2 / 12 Ultimate level of support.

With this merge by Faith Ekstrand, the fragment shading rate extension with NVK is all set for Mesa 24.3.