/*
 * (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 * Unpublished-- rights reserved under the copyright laws of the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.
 */
/*
 *  plane.c
 *  This program demonstrates the use of local versus 
 *  infinite lighting on a flat plane.
 */
#include <stdlib.h>
#include <GL/glut.h>

/*  Initialize material property, light source, and lighting model.
 */
void myinit(void)
{
    GLfloat mat_ambient[] = { 0.0, 0.0, 0.0, 1.0 };
/*   mat_specular and mat_shininess are NOT default values	*/
    GLfloat mat_diffuse[] = { 0.4, 0.4, 0.4, 1.0 };
    GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 };
    GLfloat mat_shininess[] = { 15.0 };

    GLfloat light_ambient[] = { 0.0, 0.0, 0.0, 1.0 };
    GLfloat light_diffuse[] = { 1.0, 1.0, 1.0, 1.0 };
    GLfloat light_specular[] = { 1.0, 1.0, 1.0, 1.0 };
    GLfloat lmodel_ambient[] = { 0.2, 0.2, 0.2, 1.0 };

    glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient);
    glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);
    glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
    glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);
    glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
    glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
    glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
    glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);

    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glDepthFunc(GL_LESS);
    glEnable(GL_DEPTH_TEST);
}

void drawPlane(void)
{
    glBegin (GL_QUADS);
    glNormal3f (0.0, 0.0, 1.0);
    glVertex3f (-1.0, -1.0, 0.0);
    glVertex3f (0.0, -1.0, 0.0);
    glVertex3f (0.0, 0.0, 0.0);
    glVertex3f (-1.0, 0.0, 0.0);

    glNormal3f (0.0, 0.0, 1.0);
    glVertex3f (0.0, -1.0, 0.0);
    glVertex3f (1.0, -1.0, 0.0);
    glVertex3f (1.0, 0.0, 0.0);
    glVertex3f (0.0, 0.0, 0.0);

    glNormal3f (0.0, 0.0, 1.0);
    glVertex3f (0.0, 0.0, 0.0);
    glVertex3f (1.0, 0.0, 0.0);
    glVertex3f (1.0, 1.0, 0.0);
    glVertex3f (0.0, 1.0, 0.0);

    glNormal3f (0.0, 0.0, 1.0);
    glVertex3f (0.0, 0.0, 0.0);
    glVertex3f (0.0, 1.0, 0.0);
    glVertex3f (-1.0, 1.0, 0.0);
    glVertex3f (-1.0, 0.0, 0.0);
    glEnd();
}

void display (void)
{
    GLfloat infinite_light[] = { 1.0, 1.0, 1.0, 0.0 };
    GLfloat local_light[] = { 1.0, 1.0, 1.0, 1.0 };

    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glPushMatrix ();
    glTranslatef (-1.5, 0.0, 0.0);
    glLightfv (GL_LIGHT0, GL_POSITION, infinite_light);
    drawPlane ();
    glPopMatrix ();

    glPushMatrix ();
    glTranslatef (1.5, 0.0, 0.0);
    glLightfv (GL_LIGHT0, GL_POSITION, local_light);
    drawPlane ();
    glPopMatrix ();
    glFlush ();
}

void myReshape(int w, int h)
{
    glViewport (0, 0, w, h);
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity ();
    if (w <= h) 
	glOrtho (-1.5, 1.5, -1.5*(GLdouble)h/(GLdouble)w, 
	    1.5*(GLdouble)h/(GLdouble)w, -10.0, 10.0);
    else 
	glOrtho (-1.5*(GLdouble)w/(GLdouble)h, 
	    1.5*(GLdouble)w/(GLdouble)h, -1.5, 1.5, -10.0, 10.0);
    glMatrixMode (GL_MODELVIEW);
}

/*  Main Loop
 *  Open window with initial window size, title bar, 
 *  RGBA display mode, and handle input events.
 */
int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize (500, 200);
    glutCreateWindow (argv[0]);
    myinit();
    glutReshapeFunc (myReshape);
    glutDisplayFunc(display);
    glutMainLoop();
    return 0;             /* ANSI C requires main to return int. */
}
