[ODE] body auto disable

[Adam D. Moss]

gl wrote:
> Actually, having just played with CFM I realise that good values completely
> depend on how someone is setting up their sim, so getting a global default
> might prove tricky...

I've used the technique described here and it's reasonably
effective; I also wait for rotational velocity to approach
zero, however.

Definitely hard to set up a default for, though.  The magic numbers
will depend on what unit scales the user is using and the expected
practical speed ranges of world bodies specific to that simulation.

I'm in two minds about whether auto-disabling belongs in ODE itself,
though.

On the one hand it's something that can be done from the application
itself via the API without too much pain.  On the other, grubbing
through the simulation-side scene-graph is really something that I
expect ODE itself to be better at (and more to the point it's
something that ODE will be doing anyway as part of simulation, so
the cost of walking the structures twice could be avoided).

-- 
Adam D. Moss   . ,,^^   adam@gimp.org   http://www.foxbox.org/   co:3