[ODE] Collision response for symetrical tri-meshes

[Jon Watte (ODE)]

I'm actually suggesting that you create two trimesh instances that share 
the vertex data, but use two separate index lists, which can be done 
with no addition to ODE.

Adding a check as for whether the rotation matrix has a negative 
determinant for each trimesh collision might incur more of a performance 
penalty than you might wish for. Perhaps a better option would be to 
have some kind of flag that specifies whether the trimesh itself is 
reversed or not.

Or, if the only problem is the contact normals, then you can easily 
reverse the normals post-collision, when you get the contacts back from 
dCollide(). That would probably be simplest.

Cheers,

			/ h+


Flavien Brebion wrote:
> The correct way to do it would probably be to add a flag for each 
> tri-mesh instance, and to check that flag when the triangle intersection 
> function is called. Remains the question of detecting when that should 
> be done, simply looking at the rotation matrix, and extracting the scale..