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34 * Unpublished-- rights reserved under the copyright laws of the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 * fog.c
42 * This program draws 5 red teapots, each at a different
43 * z distance from the eye, in different types of fog.
44 * Pressing the left mouse button chooses between 3 types of
45 * fog: exponential, exponential squared, and linear.
46 * In this program, there is a fixed density value, as well
47 * as fixed start and end values for the linear fog.
48 */
49 #include <stdlib.h>
50 #include <math.h>
51 #include "glut_wrap.h"
52
53 GLint fogMode;
54
55 static void
selectFog(int mode)56 selectFog(int mode)
57 {
58 switch(mode) {
59 case GL_LINEAR:
60 glFogf(GL_FOG_START, 1.0);
61 glFogf(GL_FOG_END, 5.0);
62 /* falls through */
63 case GL_EXP2:
64 case GL_EXP:
65 glFogi(GL_FOG_MODE, mode);
66 glutPostRedisplay();
67 break;
68 case 0:
69 exit(0);
70 }
71 }
72
73 /* Initialize z-buffer, projection matrix, light source,
74 * and lighting model. Do not specify a material property here.
75 */
76 static void
myinit(void)77 myinit(void)
78 {
79 GLfloat position[] =
80 {0.0, 3.0, 3.0, 0.0};
81 GLfloat local_view[] =
82 {0.0};
83
84 glEnable(GL_DEPTH_TEST);
85 glDepthFunc(GL_LESS);
86
87 glLightfv(GL_LIGHT0, GL_POSITION, position);
88 glLightModelfv(GL_LIGHT_MODEL_LOCAL_VIEWER, local_view);
89
90 glFrontFace(GL_CW);
91 glEnable(GL_LIGHTING);
92 glEnable(GL_LIGHT0);
93 glEnable(GL_AUTO_NORMAL);
94 glEnable(GL_NORMALIZE);
95 glEnable(GL_FOG);
96 {
97 GLfloat fogColor[4] =
98 {0.5, 0.5, 0.5, 1.0};
99
100 fogMode = GL_EXP;
101 glFogi(GL_FOG_MODE, fogMode);
102 glFogfv(GL_FOG_COLOR, fogColor);
103 glFogf(GL_FOG_DENSITY, 0.35);
104 glHint(GL_FOG_HINT, GL_DONT_CARE);
105 glClearColor(0.5, 0.5, 0.5, 1.0);
106 }
107 }
108
109 static void
renderRedTeapot(GLfloat x,GLfloat y,GLfloat z)110 renderRedTeapot(GLfloat x, GLfloat y, GLfloat z)
111 {
112 float mat[4];
113
114 glPushMatrix();
115 glTranslatef(x, y, z);
116 mat[0] = 0.1745;
117 mat[1] = 0.01175;
118 mat[2] = 0.01175;
119 mat[3] = 1.0;
120 glMaterialfv(GL_FRONT, GL_AMBIENT, mat);
121 mat[0] = 0.61424;
122 mat[1] = 0.04136;
123 mat[2] = 0.04136;
124 glMaterialfv(GL_FRONT, GL_DIFFUSE, mat);
125 mat[0] = 0.727811;
126 mat[1] = 0.626959;
127 mat[2] = 0.626959;
128 glMaterialfv(GL_FRONT, GL_SPECULAR, mat);
129 glMaterialf(GL_FRONT, GL_SHININESS, 0.6 * 128.0);
130 glutSolidTeapot(1.0);
131 glPopMatrix();
132 }
133
134 /* display() draws 5 teapots at different z positions.
135 */
136 static void
display(void)137 display(void)
138 {
139 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
140 renderRedTeapot(-4.0, -0.5, -1.0);
141 renderRedTeapot(-2.0, -0.5, -2.0);
142 renderRedTeapot(0.0, -0.5, -3.0);
143 renderRedTeapot(2.0, -0.5, -4.0);
144 renderRedTeapot(4.0, -0.5, -5.0);
145 glFlush();
146 }
147
148 static void
myReshape(int w,int h)149 myReshape(int w, int h)
150 {
151 glViewport(0, 0, w, h);
152 glMatrixMode(GL_PROJECTION);
153 glLoadIdentity();
154 if (w <= (h * 3))
155 glOrtho(-6.0, 6.0, -2.0 * ((GLfloat) h * 3) / (GLfloat) w,
156 2.0 * ((GLfloat) h * 3) / (GLfloat) w, 0.0, 10.0);
157 else
158 glOrtho(-6.0 * (GLfloat) w / ((GLfloat) h * 3),
159 6.0 * (GLfloat) w / ((GLfloat) h * 3), -2.0, 2.0, 0.0, 10.0);
160 glMatrixMode(GL_MODELVIEW);
161 glLoadIdentity();
162 }
163
164 static void
key(unsigned char k,int x,int y)165 key(unsigned char k, int x, int y)
166 {
167 switch (k) {
168 case 27: /* Escape */
169 exit(0);
170 break;
171 default:
172 return;
173 }
174 glutPostRedisplay();
175 }
176
177 /* Main Loop
178 * Open window with initial window size, title bar,
179 * RGBA display mode, depth buffer, and handle input events.
180 */
181 int
main(int argc,char ** argv)182 main(int argc, char **argv)
183 {
184 glutInit(&argc, argv);
185 glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
186 glutInitWindowSize(450, 150);
187 glutCreateWindow(argv[0]);
188 myinit();
189 glutReshapeFunc(myReshape);
190 glutDisplayFunc(display);
191 glutCreateMenu(selectFog);
192 glutAddMenuEntry("Fog EXP", GL_EXP);
193 glutAddMenuEntry("Fog EXP2", GL_EXP2);
194 glutAddMenuEntry("Fog LINEAR", GL_LINEAR);
195 glutAddMenuEntry("Quit", 0);
196 glutAttachMenu(GLUT_RIGHT_BUTTON);
197 glutKeyboardFunc(key);
198 glutMainLoop();
199 return 0; /* ANSI C requires main to return int. */
200 }
201