Am running into a strange problem with an installation that uses multiple video outputs.
Basically, frame rate drops to 11fps on the fullscreen output windows UNLESS the patch window slightly overlaps one of the outputs. When the edge of the patch window slightly overlaps, then framerate goes back up to 30fps.
The system has three graphics cards installed, with a projector on each output. A control monitor is connected to the second output of one of the cards.
What could be going on here? I am using OpenGL to create a separate render context for each video output, and I suspect the problem is connected to how these contexts are created, and fullscreen rendering invoked.
To make it even more mysterious, this patch + hardware configuration worked perfectly for 11 months in another setting.
This is a really weird, known but elusive issue. Very machine and OS specific. The workaround is to use @border0 and a window size with one pixel less than the screen size. As best as we can tell it is a bug in Apple’s window compositing system.