getting back the x,y values from NURBS curve?

Hi: just getting started in my first OpenGL application. The application is a vision science experiment. We have successfully defined control points and created a 2-dimensional nurbs curve, and used gluNurbsCurve to draw the curve.

However, for statistical reasons, we need to know the RMS variation of the NURBS curve from the piecewise linear function that underlies it. In order to do this, we need to have returned to us the x, y values associated with parametrically defined points along the nurbs curve.

All the routines seem to be one-way: return value void.

Is there some obvious hack that I am missing that allows a value to be returned? Only hack I can see is reading back the pixels and figuring out the values that were written!


Joe Miller
University of Arizona
Department of Ophthalmology