>What for? Windowing, I/O, audio playback, and rendering context would all be wrapped by Unity wouldn’t they? The only remaining thing I normally use OS calls for is hot-loading DLLs.
Mainly for setting the cursor position, and also some minor reading of window data like border width. I should probably change to an in-game virtual cursor implementation at some point for many reasons, and that should get written out then.
I wonder why the performance is so bad, then. Are your specs good, and these other Unity games you're running 3D? The people running on Windows don't seem to be having any issues, and I get hundreds of FPS on a 1060.