I'm working on a simple game with SFML, and the only way to make the game reasonably smooth is to allow it the highest framerate my machine can handle (that is, giving it no limit). 60 FPS in my game looks like 5 FPS in most games.
I've made sure it wasn't any weird timing issue with sf::Clock by making my delta variable constant, and I've made a simple moving square with the default SFML template to make sure it wasn't anything else in my code.
Limiting framerate using window.setFramerateLimit(80), window.setVerticalSync(true), or by placing usleep(1000 * 15), a 15-millisecond pause (~67 FPS, in theory) in the game loop, cause the terribly glitchy, asymmetric animation.
I think the problem is my Mac. I hesitate to blame anything other than my code, but I just can't explain the problem otherwise. I'm running OS X Mavericks on a 15-inch MacBook Pro with a Retina display (2.4 GHz i7, Nvidia, 8GB RAM).
Is it the Retina display, or some issue with the sleep() system calls? Any thoughts are welcome. Thanks!