GLE is a library package of C functions that draw extruded surfaces,
including surfaces of revolution, sweeps, tubes, polycones,
polycylinders and helicoids. Generically, the extruded surface is
specified with a 2D polyline that is extruded along a 3D path. A
local coordinate system allows for additional flexibility in the
primitives drawn. Extrusions may be texture mapped in a variety of
ways. The GLE library generates 3D triangle coordinates, lighting
normal vectors and texture coordinates as output. GLE uses the GL or
OpenGL API's to perform the actual rendering.