Since the beginning of Handmade Hero, I've been modifying my platform code little by little to achieve the same features as the canonical Windows Casey version. But, one important thing I can't get is consistent fps.
The game update and render loop can average 40 000 cycles and once every few seconds take up to 3X the amount. I know the timing isn't perfectly deterministic, but Casey's version prints 0.033ms/frame very consistently.
I first started with a timer that fires every 1/30 or 1/60 second, but it fluctuates a lot. I thought, maybe the timer isn't accurate, but that wouldn't explain the varying cycles in the game code which only measures the time spend from the beginning to the end of the game update and render loop.
Now that we learned how to start a different thread, I tried running the game on a different thread and as in Windows, do an "infinite" while loop and adjust the sleep if the game runs too fast than the target ms/frame, but the results are not better, although different...
What's your experience with this? Is this harder to get right on OS X? This seems a trivial issue, so I can't see what I'd be doing wrong.
Note: I run the game at only 640-by-360, to make sure my 2008 laptop should be able to hit a consistent fps.