#       glu_test
#
#  same as cube but uses a glu function to test
#  that glu stuff is working
use OpenGL;
  
sub wirecube{
    # adapted from libaux
    local($s) = @_;
    local(@x,@y,@z,@f);
    local($i,$j,$k);
    $s = $s/2.0;
    @x=(-$s,-$s,-$s,-$s,$s,$s,$s,$s);
    @y=(-$s,-$s,$s,$s,-$s,-$s,$s,$s);
    @z=(-$s,$s,$s,-$s,-$s,$s,$s,-$s);
    @f=( 
        0, 1, 2, 3,
        3, 2, 6, 7,
        7, 6, 5, 4,
        4, 5, 1, 0,
        5, 6, 2, 1,
        7, 4, 0, 3,
        );
    for($i=0;$i<6;$i++){
        glBegin(GL_LINE_LOOP);
        for($j=0;$j<4;$j++){
                $k=$f[$i*4+$j];
                glVertex3d($x[$k],$y[$k],$z[$k]);
        }
        glEnd();
    }
}
sub display{
    glClear(GL_COLOR_BUFFER_BIT);
    glColor3f(1.0, 1.0, 1.0);
    glLoadIdentity();   #  clear the matrix
    glTranslatef(0.0, 0.0, -5.0);       #  viewing transformation
    glScalef(1.0, 2.0, 1.0);    #  modeling transformation
    wirecube(1.0);
    glpFlush();
}
  
sub myReshape {
    # glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    # using gluPerspective instead of glFrustum to test glu library
    #glFrustum(-1.0, 1.0, -1.0, 1.0, 1.5, 20.0);
    gluPerspective(30.0,1.0,1.0,30.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity ();
}
glpOpenWindow;
glShadeModel(GL_FLAT);
myReshape();
display();
glpMainLoop;