[ODE] Fixed timestep loop woes

[Jon Watte (ODE)]

> But I have also read this: http://www.gaffer.org/articles/Timestep.html
> 
> Wich basicly is what I'm doing, except the last thing were the author 
> suggest having two states (previous and current) around and interpolating 
> between them to get a new state wich is then rendered.

If your timestep is smaller than your typical frame time, then it's 
seldom worth it. Interpolation helps more when you have a network 
involved, so the intervals between updates may be large. However, if you 
want to do it, then there's an alternate description here:

http://www.mindcontrol.org/~hplus/graphics/game_loop.html

I've toyed with it in conjunction with ODE, but never found it to be 
necessary.

Note that you don't need to keep two steps around; ODE gives you the 
position and velocity, so you can interpolate based on the 
point-and-vector instead. (Same thing for orientation and avel)

Cheers,

			/ h+