[ODE] Randomness in ODE

[ODE User]

> No, this is pretty much what you need to do.  It's also what Doom & Quake
> do with "demo recording."  Among other things, it allows recamming,
> editing and machinima, i.e. making (non-interactive) movies with the Quake
> engine:

Most games store the user input, not the actual position/orientation/pose
of the entities. You can put cameras wherever you want, as physical
simulation shouldn't be affected by camera position at all (neither on
record nor on replay).

You could do a compromise. Run UI at a fixed rate (60 fps on a console,
probably 10 fps on a simple networked game) and save all the UI, but save
the full baseline, say, every 5 seconds, so that you don't get too much
off track. This will still be a bigger file than just saving UI, but it's
probably going to be a good compromise.

In fact, being able to record UI and play it back, and get to the same
spot, is a very useful tool for debugging, and if you check the mailing
list archives for GDAlgorithms, you will see that this is the preferred
method for most shipping games (that gave a response at all :-)

Cheers,

				/ h+