gluTessNormal Interface to
OpenGL function gluTessNormal
usage: gluTessNormal( tess, valueX, valueY, valueZ )
C function: void gluTessNormal(GLUtesselator* tess, GLdouble valueX, GLdouble valueY, GLdouble valueZ)
Psychtoolbox/PsychOpenGL/MOGL/wrap/gluTessNormal.m