src/redbook/clip.c

   1 /*
   2  * Copyright (c) 1993-1997, Silicon Graphics, Inc.
   3  * ALL RIGHTS RESERVED
   4  * Permission to use, copy, modify, and distribute this software for
   5  * any purpose and without fee is hereby granted, provided that the above
   6  * copyright notice appear in all copies and that both the copyright notice
   7  * and this permission notice appear in supporting documentation, and that
   8  * the name of Silicon Graphics, Inc. not be used in advertising
   9  * or publicity pertaining to distribution of the software without specific,
  10  * written prior permission.
  11  *
  12  * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
  13  * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
  14  * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
  15  * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
  16  * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
  17  * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
  18  * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
  19  * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
  20  * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
  21  * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
  22  * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
  23  * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
  24  *
  25  * US Government Users Restricted Rights
  26  * Use, duplication, or disclosure by the Government is subject to
  27  * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
  28  * (c)(1)(ii) of the Rights in Technical Data and Computer Software
  29  * clause at DFARS 252.227-7013 and/or in similar or successor
  30  * clauses in the FAR or the DOD or NASA FAR Supplement.
  31  * Unpublished-- rights reserved under the copyright laws of the
  32  * United States.  Contractor/manufacturer is Silicon Graphics,
  33  * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
  34  *
  35  * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
  36  */
  37
  38 /*
  39  *  clip.c
  40  *  This program demonstrates arbitrary clipping planes.
  41  */
  42 #include <GL/glut.h>
  43 #include <stdlib.h>
  44
  45 void init(void)
  46 {
  47    glClearColor (0.0, 0.0, 0.0, 0.0);
  48    glShadeModel (GL_FLAT);
  49 }
  50
  51 void display(void)
  52 {
  53    GLdouble eqn[4] = {0.0, 1.0, 0.0, 0.0};
  54    GLdouble eqn2[4] = {1.0, 0.0, 0.0, 0.0};
  55
  56    glClear(GL_COLOR_BUFFER_BIT);
  57
  58    glColor3f (1.0, 1.0, 1.0);
  59    glPushMatrix();
  60    glTranslatef (0.0, 0.0, -5.0);
  61
  62 /*    clip lower half -- y < 0          */
  63    glClipPlane (GL_CLIP_PLANE0, eqn);
  64    glEnable (GL_CLIP_PLANE0);
  65 /*    clip left half -- x < 0           */
  66    glClipPlane (GL_CLIP_PLANE1, eqn2);
  67    glEnable (GL_CLIP_PLANE1);
  68
  69    glRotatef (90.0, 1.0, 0.0, 0.0);
  70    glutWireSphere(1.0, 20, 16);
  71    glPopMatrix();
  72
  73    glFlush ();
  74 }
  75
  76 void reshape (int w, int h)
  77 {
  78    glViewport (0, 0, (GLsizei) w, (GLsizei) h);
  79    glMatrixMode (GL_PROJECTION);
  80    glLoadIdentity ();
  81    gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);
  82    glMatrixMode (GL_MODELVIEW);
  83 }
  84
  85 /* ARGSUSED1 */
  86 void keyboard(unsigned char key, int x, int y)
  87 {
  88    switch (key) {
  89       case 27:
  90          exit(0);
  91          break;
  92    }
  93 }
  94
  95 int main(int argc, char** argv)
  96 {
  97    glutInit(&argc, argv);
  98    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
  99    glutInitWindowSize (500, 500);
 100    glutInitWindowPosition (100, 100);
 101    glutCreateWindow (argv[0]);
 102    init ();
 103    glutDisplayFunc(display);
 104    glutReshapeFunc(reshape);
 105    glutKeyboardFunc(keyboard);
 106    glutMainLoop();
 107    return 0;
 108 }