[ODE] Player control

[Megan Fox]

The probelm that at least I ran into with non-floating bodies was that
movement got very, very strange on uneven terrain.  To get the player
body moving up stairs, for instance, required exerting such a force
that, if applied in normal cases, had the player pushing objects 20x
her mass around as if they were nothing.

Now I suppose you could separate "movement bodies" from "bodies that
interact rigidly", and do some special-case modelling of stairs and
similar geometry as ramps for the purposes of collision with mobile
bodies wanting to slide up them... etc... but that gets complex and
strange fast.

I guess it depends on your game, really.  For FPS's with reasonably
flat terrain, the standard dragging sphere probably makes perfect
sense - for RPGs that involve lots of stairs or other weird floor
geometry, it seems like the floating body is a better idea.

Just my 2c
-Megan



> Other people use a ccylinder (or sphere) that floats above
> ground, with a ray down to the ground, and simulate a spring
> to keep the pelvis a certain amount above ground (and use IK
> to plant feet). This may make crouching easier, but also may
> mean you're penetrating between, say, left leg and a rock.