progs/redbook/polyoff.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  31  * Unpublished-- rights reserved under the copyright laws of the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  *  polyoff.c
  40  *  This program demonstrates polygon offset to draw a shaded
  41  *  polygon and its wireframe counterpart without ugly visual
  42  *  artifacts ("stitching").
  43  */
  44 #include <GL/glut.h>
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47
  48 #ifdef GL_VERSION_1_1
  49 GLuint list;
  50 GLint spinx = 0;
  51 GLint spiny = 0;
  52 GLfloat tdist = 0.0;
  53 GLfloat polyfactor = 1.0;
  54 GLfloat polyunits = 1.0;
  55
  56 /*  display() draws two spheres, one with a gray, diffuse material,
  57  *  the other sphere with a magenta material with a specular highlight.
  58  */
  59 void display (void)
  60 {
  61     GLfloat gray[] = { 0.8, 0.8, 0.8, 1.0 };
  62     GLfloat black[] = { 0.0, 0.0, 0.0, 1.0 };
  63
  64     glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  65     glPushMatrix ();
  66     glTranslatef (0.0, 0.0, tdist);
  67     glRotatef ((GLfloat) spinx, 1.0, 0.0, 0.0);
  68     glRotatef ((GLfloat) spiny, 0.0, 1.0, 0.0);
  69
  70     glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, gray);
  71     glMaterialfv(GL_FRONT, GL_SPECULAR, black);
  72     glMaterialf(GL_FRONT, GL_SHININESS, 0.0);
  73     glEnable(GL_LIGHTING);
  74     glEnable(GL_LIGHT0);
  75     glEnable(GL_POLYGON_OFFSET_FILL);
  76     glPolygonOffset(polyfactor, polyunits);
  77     glCallList (list);
  78     glDisable(GL_POLYGON_OFFSET_FILL);
  79
  80     glDisable(GL_LIGHTING);
  81     glDisable(GL_LIGHT0);
  82     glColor3f (1.0, 1.0, 1.0);
  83     glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
  84     glCallList (list);
  85     glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
  86
  87     glPopMatrix ();
  88     glFlush ();
  89 }
  90
  91 /*  specify initial properties
  92  *  create display list with sphere
  93  *  initialize lighting and depth buffer
  94  */
  95 void gfxinit (void)
  96 {
  97     GLfloat light_ambient[] = { 0.0, 0.0, 0.0, 1.0 };
  98     GLfloat light_diffuse[] = { 1.0, 1.0, 1.0, 1.0 };
  99     GLfloat light_specular[] = { 1.0, 1.0, 1.0, 1.0 };
 100     GLfloat light_position[] = { 1.0, 1.0, 1.0, 0.0 };
 101
 102     GLfloat global_ambient[] = { 0.2, 0.2, 0.2, 1.0 };
 103
 104     glClearColor (0.0, 0.0, 0.0, 1.0);
 105
 106     list = glGenLists(1);
 107     glNewList (list, GL_COMPILE);
 108        glutSolidSphere(1.0, 20, 12);
 109     glEndList ();
 110
 111     glEnable(GL_DEPTH_TEST);
 112
 113     glLightfv (GL_LIGHT0, GL_AMBIENT, light_ambient);
 114     glLightfv (GL_LIGHT0, GL_DIFFUSE, light_diffuse);
 115     glLightfv (GL_LIGHT0, GL_SPECULAR, light_specular);
 116     glLightfv (GL_LIGHT0, GL_POSITION, light_position);
 117     glLightModelfv (GL_LIGHT_MODEL_AMBIENT, global_ambient);
 118 }
 119
 120 /*  call when window is resized  */
 121 void reshape(int width, int height)
 122 {
 123     glViewport (0, 0, width, height);
 124     glMatrixMode (GL_PROJECTION);
 125     glLoadIdentity ();
 126     gluPerspective(45.0, (GLdouble)width/(GLdouble)height,
 127             1.0, 10.0);
 128     glMatrixMode (GL_MODELVIEW);
 129     glLoadIdentity ();
 130     gluLookAt (0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
 131 }
 132
 133 /*  call when mouse button is pressed  */
 134 /* ARGSUSED2 */
 135 void mouse(int button, int state, int x, int y) {
 136     switch (button) {
 137         case GLUT_LEFT_BUTTON:
 138             switch (state) {
 139                 case GLUT_DOWN:
 140                     spinx = (spinx + 5) % 360;
 141                     glutPostRedisplay();
 142                     break;
 143                 default:
 144                     break;
 145             }
 146             break;
 147         case GLUT_MIDDLE_BUTTON:
 148             switch (state) {
 149                 case GLUT_DOWN:
 150                     spiny = (spiny + 5) % 360;
 151                     glutPostRedisplay();
 152                     break;
 153                 default:
 154                     break;
 155             }
 156             break;
 157         case GLUT_RIGHT_BUTTON:
 158             switch (state) {
 159                 case GLUT_UP:
 160                     exit(0);
 161                     break;
 162                 default:
 163                     break;
 164             }
 165             break;
 166         default:
 167             break;
 168     }
 169 }
 170
 171 /* ARGSUSED1 */
 172 void keyboard (unsigned char key, int x, int y)
 173 {
 174    switch (key) {
 175       case 't':
 176          if (tdist < 4.0) {
 177             tdist = (tdist + 0.5);
 178             glutPostRedisplay();
 179          }
 180          break;
 181       case 'T':
 182          if (tdist > -5.0) {
 183             tdist = (tdist - 0.5);
 184             glutPostRedisplay();
 185          }
 186          break;
 187       case 'F':
 188          polyfactor = polyfactor + 0.1;
 189          printf ("polyfactor is %f\n", polyfactor);
 190          glutPostRedisplay();
 191          break;
 192       case 'f':
 193          polyfactor = polyfactor - 0.1;
 194          printf ("polyfactor is %f\n", polyfactor);
 195          glutPostRedisplay();
 196          break;
 197       case 'U':
 198          polyunits = polyunits + 1.0;
 199          printf ("polyunits is %f\n", polyunits);
 200          glutPostRedisplay();
 201          break;
 202       case 'u':
 203          polyunits = polyunits - 1.0;
 204          printf ("polyunits is %f\n", polyunits);
 205          glutPostRedisplay();
 206          break;
 207       default:
 208          break;
 209    }
 210 }
 211
 212 /*  Main Loop
 213  *  Open window with initial window size, title bar,
 214  *  RGBA display mode, and handle input events.
 215  */
 216 int main(int argc, char** argv)
 217 {
 218     glutInit(&argc, argv);
 219     glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
 220     glutCreateWindow(argv[0]);
 221     glutReshapeFunc(reshape);
 222     glutDisplayFunc(display);
 223     glutMouseFunc(mouse);
 224     glutKeyboardFunc(keyboard);
 225     gfxinit();
 226     glutMainLoop();
 227     return 0;
 228 }
 229 #else
 230 int main(int argc, char** argv)
 231 {
 232     fprintf (stderr, "This program demonstrates a feature which is not in OpenGL Version 1.0.\n");
 233     fprintf (stderr, "If your implementation of OpenGL Version 1.0 has the right extensions,\n");
 234     fprintf (stderr, "you may be able to modify this program to make it run.\n");
 235     return 0;
 236 }
 237 #endif