/* 
 *  By Binh Phu Le
 *  parts of this program might have been adopted from or inspired by 
 *  sample programs in 
 *  "OpenGL Programming Guide", 
 *  Copyright (c) 1993-1997, Silicon Graphics, Inc.
 *  "Interactive Computer Graphics"  
 *  Copyright (c) 1997, Addison-Wesley,
 *  and/or those written by Dr. Sumanta Guha guha@cs.uwm.edu
 *  and/or those written by Dr. Ichiro Suzuki suzuki@cs.uwm.edu
 */