/*
 * Copyright (c) 1993-1997, 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 * Unpublished-- rights reserved under the copyright laws of the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(R) is a registered trademark of Silicon Graphics, Inc.
 */

/*
 *  clip.c
 *  This program demonstrates arbitrary clipping planes.
 */
#include <GL/glut.h>
#include <stdlib.h>

/* Minimum stack space */
static USED const char *stack = "$STACK:65535"; 

void init(void) 
{
	GLdouble eqn[4] = {0.0, 1.0, 0.0, 0.0};
	GLdouble eqn2[4] = {1.0, 0.0, 0.0, 0.0};
	glClearColor (0.0, 0.0, 0.0, 0.0);
	glShadeModel (GL_FLAT);

	/*    clip lower half -- y < 0          */
	glClipPlane (GL_CLIP_PLANE0, eqn);
	glEnable (GL_CLIP_PLANE0);
	/*    clip left half -- x < 0           */
	glClipPlane (GL_CLIP_PLANE1, eqn2);
	glEnable (GL_CLIP_PLANE1);
}

void display(void)
{
	glClear(GL_COLOR_BUFFER_BIT);

	glColor3f (1.0, 1.0, 1.0);
	glPushMatrix();
	glTranslatef (0.0, 0.0, -5.0);


	glRotatef (90.0, 1.0, 0.0, 0.0);
	glutWireSphere(1.0, 20, 16);
	glPopMatrix();

	glFlush ();
}

void reshape (int w, int h)
{
	glViewport (0, 0, (GLsizei) w, (GLsizei) h); 
	glMatrixMode (GL_PROJECTION);
	glLoadIdentity ();
	gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);
	glMatrixMode (GL_MODELVIEW);
}

/* ARGSUSED1 */
void keyboard(unsigned char key, int x, int y)
{
	switch (key) {
	case 27:
		exit(0);
		break;
	case '1':
		glEnable (GL_CLIP_PLANE0);
		glEnable (GL_CLIP_PLANE1);
		break;
	case '0':
		glDisable (GL_CLIP_PLANE0);
		glDisable (GL_CLIP_PLANE1);
		break;      
	}
	glutPostRedisplay();
}

int main(int argc, char** argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
	glutInitWindowSize (500, 500); 
	glutInitWindowPosition (100, 100);
	glutCreateWindow (argv[0]);
	init ();
	glutDisplayFunc(display); 
	glutReshapeFunc(reshape);
	glutKeyboardFunc(keyboard);
	glutMainLoop();
	return 0;
}