#
# (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# Unpublished-- rights reserved under the copyright laws of the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.
#/
#  bezsurf.c
#  This program renders a lighted, filled Bezier surface,
#  using two-dimensional evaluators.
#/

use opengl;
package opengl;

@ctrlpoints = (
    [[-1.5, -1.5, 4.0], [-0.5, -1.5, 2.0], [0.5, -1.5, -1.0],[1.5, -1.5, 2.0]],
    [[-1.5, -0.5, 1.0],[-0.5, -0.5, 3.0],[0.5, -0.5, 0.0], [1.5, -0.5, -1.0]],
    [[-1.5, 0.5, 4.0], [-0.5, 0.5, 0.0],[0.5, 0.5, 3.0], [1.5, 0.5, 4.0]],
    [[-1.5, 1.5, -2.0], [-0.5, 1.5, -2.0], [0.5, 1.5, 0.0], [1.5, 1.5, -1.0]]
	       );

sub makectrlpts {
     my $array = array_float(4*4*3);
     my $m = 0;
     for ($i = 0; $i < 4; $i++) {
	 for ($j = 0; $j < 4; $j++) {
	     for ($k = 0; $k < 3; $k++) {
		 set_float($array,$m,$ctrlpoints[$i][$j][$k]);
		 $m++;
	     }
	 }
     }
     return $array;
 }

sub initlights {
    my $ambient = newfv4(0.2, 0.2, 0.2, 1.0);
    my $position = newfv4(0.0,0.0,2.0,1.0);
    my $mat_diffuse = newfv4(0.6,0.6,0.6,1.0);
    my $mat_specular = newfv4(1.0, 1.0, 1.0, 1.0);
    my $mat_shininess =  newfv4(50.0,0,0,0);
    glEnable($GL_LIGHTING);
    glEnable($GL_LIGHT0);
    glLightfv($GL_LIGHT0, $GL_AMBIENT, $ambient);
    glLightfv($GL_LIGHT0, $GL_POSITION, $position);
    glMaterialfv($GL_FRONT, $GL_DIFFUSE, $mat_diffuse);
    glMaterialfv($GL_FRONT, $GL_SPECULAR, $mat_specular);
    glMaterialfv($GL_FRONT, $GL_SHININESS, $mat_shininess);
}

sub display {
    glClear($GL_COLOR_BUFFER_BIT | $GL_DEPTH_BUFFER_BIT);
    glPushMatrix();
    glRotatef(85.0, 1.0, 1.0, 1.0);
    glEvalMesh2($GL_FILL, 0, 20, 0, 20);
    glPopMatrix();
    glFlush();
}

sub myinit {
    glClearColor (0.0, 0.0, 0.0, 1.0);
    glEnable ($GL_DEPTH_TEST);
    my $cpoints = makectrlpts();
    glMap2f($GL_MAP2_VERTEX_3, 0, 1, 3, 4, 0,1,12,4, $cpoints);
    glEnable($GL_MAP2_VERTEX_3);
    glEnable($GL_AUTO_NORMAL);
    glEnable($GL_NORMALIZE);
    glMapGrid2f(20, 0.0, 1.0, 20, 0.0, 1.0);
    initlights();
    free($cpoints);
}


sub myReshape {
    my ($w,$h) = @_;
    glViewport(0, 0, $w, $h);
    glMatrixMode($GL_PROJECTION);
    glLoadIdentity();
    if ($w <= $h) {
	glOrtho(-4.0, 4.0, -4.0*$h/$w, 4.0*$h/$w, -4.0, 4.0);
    } else {
	glOrtho(-4.0*$w/$h, 4.0*$w/$h, -4.0, 4.0, -4.0, 4.0);
    }
    glMatrixMode($GL_MODELVIEW);
    glLoadIdentity();
}

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