(Sep 4, 2010 07:58 PM)Skorche Wrote:  You could do a small step at the end to use up the rest of the time for the frame, but one of the benefits... (blah blah blah)

And I meant to end with: but if your game is simple enough this all probably doesn't matter. So yeah, as AnotherJake say, go ahead and try it. Nothing is hurt by experimenting.

It does work fine for my simple physics code. But if I used your chipmunk library, it would be a lot better with a fixed timestep right? But how would I interpolate between states when chipmunk manages all the objects ?

Chipmunk works better with fixed size timesteps yes.

Same way you would if you were managing the physics state. You only interpolate when drawing, not when updating the state. You don't have to store the interpolated values anywhere.

So should I just pass the previous and current game state and the alpha value to the renderer? Or should have a method of the Game class that creates a new interpolating instance based on the previous current and alpha and then pass that to the renderer?

I call my states alpha, beta, and the interpolated one iota. Alpha is the newest tick, beta is the previous tick. I pass alpha and beta to my interpolator to create the new state, iota. iota is the one that the renderer reads to draw.