Zink Seeing macOS Support For OpenGL Over Vulkan Then MoltenVK On Top Of Metal
The Zink Gallium3D driver that implements OpenGL on top of Vulkan has been on quite a roll recently... Beyond reaching OpenGL 4.6 support in yet-to-be-merged patches and passing ~97% of the Piglit OpenGL tests and increasingly good performance compared to Intel's OpenGL driver, the latest interesting milestone is seeing initial work on bringing Zink to macOS.
Given Apple's been phasing out support for OpenGL (and OpenCL), Zink on macOS holds merit -- arguably even more so than Linux where there still is great OpenGL drivers available for all major hardware. With the forthcoming macOS 11.0 "Big Sur", the OpenGL support will ultimately be either in a poor state or outright removed. For several years now Apple has been pushing for the OpenGL/OpenCL deprecation in their software ecosystem to instead emphasize their in-house Metal API. But with there still being plenty of macOS software out there making use of OpenGL as well as use-cases like running Wine/CrossOver for Windows software on macOS, Zink on macOS is an interesting candidate moving forward.
Zink on macOS is functioning by in turn leveraging MoltenVK for much of the Vulkan API atop Apple's native Metal drivers. So the full stack is indeed OpenGL on top of Vulkan (Zink) and then Vulkan on top of Metal (MoltenVK).
These patches to Zink are pending for the MoltenVK support with just some basic changes required.
Separately, Mike Blumenkrantz who has been devoting much of his time to Zink also noted that Red Hat's Adam Jackson has been working on Vulkan WSI integration for Zink. Those windowing system integration improvements can lead to further enhancing the Zink performance.