[ODE] 16 bits indices and TriMesh

[Erwin de Vries]

> > Is there any other way working around this problem than me cloning
> > indexbuffers or changing my renderingengine to using 32bits indices
instead of
> > 16bits?
> You can enable MeshInterface callbacks by defining
> #define OPC_USE_CALLBACKS
>
> And then changing the trimesh code to setup the callbacks to generate the
> triangle vertices.
>
> If performance is a problem it might be worth making a new #define in
> MeshInterface and changing the mesh data to shorts.

Hmm. I think indeed we should support 16 bit indices. Together with double
support this will lead to 6 different TriMeshBuild functions.

Erwin