[ODE] ODE Unstable Commit: Trimesh Preprocessing

[Colin Bonstead]

Ok, it took me about a half hour, but I finally did a commit to the ODE 
unstable branch.  For anyone else trying to do this, make sure you're 
logged in via SSH, otherwise it won't let you commit.

Anyway, what I committed is a patch I did last year to add trimesh 
preprocessing.  I based it on the chapter "Fast Contact Reduction for 
Dynamics Simulation" in Game Programming Gems 4.  Basically it's just 
marking all the interior and concave edges (and their vertices) as 
ignorable.  It requires an extra byte of memory for each triangle if you 
use it.  (If you don't call the preprocess function on your trimesh it 
should function the same way as before, and not allocate any extra 
memory.)

To use it, just call the function dGeomTriMeshDataPreprocess on your 
trimesh.  Once you've done that the data is cached and ready for use by 
the colliders.  Currently, only the ccylinder-trimesh collider uses the 
data, since that's the only one I use.  However, it should be fairly 
easy to add it to any of the other colliders, if someone wants to do 
that.

If you want to cache the preprocessed data so you don't have to compute 
it every time you start your simulation, you can use the functions 
dGeomTriMeshDataGetBuffer and dGeomTriMeshDataSetBuffer.

Colin Bonstead
Cyan Worlds, Inc