The Vulkan API has been updated once again with the latest 1.2.177 spec update available, and curiously it pulls in a new extension to help API translation layers.
VK_EXT_provoking_vertex is the new extension worked on by the likes of Google, ARM, Valve, NVIDIA, AMD and others. This isn't the first time Vulkan has gained an extension to help a translation layer, as we've seen in the past developers who work on DXVK also help with extensions.
Here's what VK_EXT_provoking_vertex will be used for:
This extension allows changing the provoking vertex convention between Vulkan’s default convention (first vertex) and OpenGL’s convention (last vertex).
This extension is intended for use by API-translation layers that implement APIs like OpenGL on top of Vulkan, and need to match the source API’s provoking vertex convention. Applications using Vulkan directly should use Vulkan’s default convention.
Mike Blumenkrantz is one of the developers mentioned who contributed to it for Valve. Blumenkrantz has been working on Zink, the OpenGL implementation on top of Vulkan so it's not entirely surprising. Hopefully this will help Zink continue getting even better and eventually we might even see Zink give older OpenGL games perhaps better performance through the use of Vulkan.