I was wondering if it was safe to make GL calls with multiple threads. Basically I'm using a GLUtesselator and was wondering if I could divide the objects to draw into 4 and assign a thread to each one.

I'm just wondering if this would cause trouble since the tesselator uses callback functions. Can 2 threads run the same callback at the same time as long as that callback does not access ant global variables?

Are there also other ways I could optimize OpenGL drawing using multithreading?

Thanks