The problem with the GLU tessellation routines does appear to have been an indirection-level problem. Basically I'd been passing a byref( func ) instead of a func into the function. The reason for that is that the data-type of the argument wouldn't accept bald func, so I'd assumed it was a pointer-to-a-function. In fact it was just a matter of having large numbers of possible types for that argument.

For right now I'm creating 12 different versions of the gluTessCallback function, one for each function type and calling the appropriate one based on the "which" argument.

Also updated to work with the latest ctypes branch_1_0 sources, mostly just finding the find_library function, now renamed to findLib. I haven't looked yet, but I'm expecting to have a similar issue with the NURBS API in GLU. Will look at that some other day, as I likely need to get on the road now to hit Alexei's thing on time.