# (c) Copyright 1993, Silicon Graphics, Inc.
# ALL RIGHTS RESERVED 
# Permission to use, copy, modify, and distribute this software for 
# any purpose and without fee is hereby granted, provided that the above
# copyright notice appear in all copies and that both the copyright notice
# and this permission notice appear in supporting documentation, and that 
# the name of Silicon Graphics, Inc. not be used in advertising
# or publicity pertaining to distribution of the software without specific,
# written prior permission. 
#
# THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
# AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
# INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
# FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
# GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
# SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
# KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
# LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
# THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
# ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
# ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
# POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
# 
# US Government Users Restricted Rights 
# Use, duplication, or disclosure by the Government is subject to
# restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
# (c)(1)(ii) of the Rights in Technical Data and Computer Software
# clause at DFARS 252.227-7013 and/or in similar or successor
# clauses in the FAR or the DOD or NASA FAR Supplement.
# Unpublished-- rights reserved under the copyright laws of the
# United States.  Contractor/manufacturer is Silicon Graphics,
# Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
#
# OpenGL(TM) is a trademark of Silicon Graphics, Inc.
#/
#
#  light.c
#  This program demonstrates the use of the OpenGL lighting 
#  model.  A sphere is drawn using a grey material characteristic. 
#  A single light source illuminates the object.
#/

use opengl;
package opengl;

sub myinit {
     my $mat_specular = newfv4( 1.0, 1.0, 1.0, 1.0 );
     my $mat_shininess = newfv4( 50.0 ,0,0,0);
     my $light_position = newfv4( 1.0, 1.0, 1.0, 0.0 );
     glMaterialfv($GL_FRONT, $GL_SPECULAR, $mat_specular);
     glMaterialfv($GL_FRONT, $GL_SHININESS, $mat_shininess);
     glLightfv($GL_LIGHT0, $GL_POSITION, $light_position);
     glEnable($GL_LIGHTING);
     glEnable($GL_LIGHT0);
     glDepthFunc($GL_LESS);
     glEnable($GL_DEPTH_TEST);
}

sub display {
     glClear($GL_COLOR_BUFFER_BIT | $GL_DEPTH_BUFFER_BIT);
     auxSolidSphere(1.0);
     glFlush();
}

sub myReshape {
    my ($w,$h) = @_;
    glViewport(0, 0, $w, $h);
    glMatrixMode($GL_PROJECTION);
    glLoadIdentity();
    if ($w <= $h) {
	glOrtho (-1.5, 1.5, -1.5*$h/$w, 1.5*$h/$w, -10.0, 10.0);
    } else {
	glOrtho (-1.5*$w/$h,  1.5*$w/$h, -1.5, 1.5, -10.0, 10.0);
    }
    glMatrixMode($GL_MODELVIEW);
    glLoadIdentity();
}

auxInitDisplayMode ($AUX_SINGLE | $AUX_RGB | $AUX_DEPTH);
auxInitPosition (0, 0, 500, 500);
auxInitWindow ("light");
myinit();
myReshape(500,500);
display();
sleep(10);
