A question about how timing/frame rate is setup in most 2d games, or 2d games that utilize a 3d api such as OpenGL.  I'm coming from a more traditional animation background, where you're typically working with a standard of 24 frames a second.  However, in games typically the framerate can be variable, depending on hardware and so on, correct?  How does this typically affect planning out how to time a sprite, or how long to have the frame of an animation play for.  For example, if you've heard of the term "Shooting on two's" which means to have a drawing display for two frames (instead of one), how can you plan for this in a game, when the frame rate could be variable? Or, am I just making this too difficult, and you plan to have a steady framerate of 24 or 30?