1
2/* Copyright (c) Mark J. Kilgard, 1994. */
3
4/*
5 * (c) Copyright 1993, Silicon Graphics, Inc.
6 * ALL RIGHTS RESERVED
7 * Permission to use, copy, modify, and distribute this software for
8 * any purpose and without fee is hereby granted, provided that the above
9 * copyright notice appear in all copies and that both the copyright notice
10 * and this permission notice appear in supporting documentation, and that
11 * the name of Silicon Graphics, Inc. not be used in advertising
12 * or publicity pertaining to distribution of the software without specific,
13 * written prior permission.
14 *
15 * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
16 * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
17 * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
18 * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
19 * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
20 * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
21 * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
22 * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
23 * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
24 * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
25 * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
26 * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
27 *
28 * US Government Users Restricted Rights
29 * Use, duplication, or disclosure by the Government is subject to
30 * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
31 * (c)(1)(ii) of the Rights in Technical Data and Computer Software
32 * clause at DFARS 252.227-7013 and/or in similar or successor
33 * clauses in the FAR or the DOD or NASA FAR Supplement.
34 * Unpublished-- rights reserved under the copyright laws of the
35 * United States.  Contractor/manufacturer is Silicon Graphics,
36 * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
37 *
38 * OpenGL(TM) is a trademark of Silicon Graphics, Inc.
39 */
40/*
41 *  depthcue.c
42 *  This program draws a wireframe model, which uses
43 *  intensity (brightness) to give clues to distance.
44 *  Fog is used to achieve this effect.
45 */
46#include <stdlib.h>
47#include "glut_wrap.h"
48
49/*  Initialize linear fog for depth cueing.
50 */
51static void myinit(void)
52{
53    GLfloat fogColor[4] = {0.0, 0.0, 0.0, 1.0};
54
55    glEnable(GL_FOG);
56    glFogi (GL_FOG_MODE, GL_LINEAR);
57    glHint (GL_FOG_HINT, GL_NICEST);  /*  per pixel   */
58    glFogf (GL_FOG_START, 3.0);
59    glFogf (GL_FOG_END, 5.0);
60    glFogfv (GL_FOG_COLOR, fogColor);
61    glClearColor(0.0, 0.0, 0.0, 1.0);
62
63    glDepthFunc(GL_LESS);
64    glEnable(GL_DEPTH_TEST);
65    glShadeModel(GL_FLAT);
66}
67
68/*  display() draws an icosahedron.
69 */
70static void display(void)
71{
72    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
73    glColor3f (1.0, 1.0, 1.0);
74    glutWireIcosahedron();
75    glFlush();
76}
77
78static void myReshape(int w, int h)
79{
80    glViewport(0, 0, w, h);
81    glMatrixMode(GL_PROJECTION);
82    glLoadIdentity();
83    gluPerspective (45.0, (GLfloat) w/(GLfloat) h, 3.0, 5.0);
84    glMatrixMode(GL_MODELVIEW);
85    glLoadIdentity ();
86    glTranslatef (0.0, 0.0, -4.0);  /*  move object into view   */
87}
88
89static void
90key(unsigned char k, int x, int y)
91{
92  switch (k) {
93  case 27:  /* Escape */
94    exit(0);
95    break;
96  default:
97    return;
98  }
99  glutPostRedisplay();
100}
101
102/*  Main Loop
103 */
104int main(int argc, char** argv)
105{
106    glutInit(&argc, argv);
107    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
108    glutCreateWindow(argv[0]);
109    myinit();
110    glutReshapeFunc(myReshape);
111    glutDisplayFunc(display);
112    glutKeyboardFunc(key);
113    glutMainLoop();
114    return 0;             /* ANSI C requires main to return int. */
115}
116