1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
|
/* Copyright (c) Mark J. Kilgard, 1994. */
/**
* (c) Copyright 1993, 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* Unpublished-- rights reserved under the copyright laws of the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(TM) is a trademark of Silicon Graphics, Inc.
*/
/*
* fog.c
* This program draws 5 red teapots, each at a different
* z distance from the eye, in different types of fog.
* Pressing the left mouse button chooses between 3 types of
* fog: exponential, exponential squared, and linear.
* In this program, there is a fixed density value, as well
* as fixed start and end values for the linear fog.
*/
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>
GLint fogMode;
void
selectFog(int mode)
{
switch(mode) {
case GL_LINEAR:
glFogf(GL_FOG_START, 1.0);
glFogf(GL_FOG_END, 5.0);
/* falls through */
mode = 0xfff;
case GL_EXP2:
case GL_EXP:
glFogiv(0xf/*GL_FOG_MODE*/, (int *) &mode);
glutPostRedisplay();
break;
case 0:
exit(0);
}
}
/* Initialize z-buffer, projection matrix, light source,
* and lighting model. Do not specify a material property here.
*/
void
myinit(void)
{
GLfloat position[] =
{0.0, 3.0, 3.0, 0.0};
GLfloat local_view[] =
{0.0};
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
glLightfv(GL_LIGHT0, GL_POSITION, position);
glLightModelfv(GL_LIGHT_MODEL_LOCAL_VIEWER, local_view);
glFrontFace(GL_CW);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_AUTO_NORMAL);
glEnable(GL_NORMALIZE);
glEnable(GL_FOG);
{
GLfloat fogColor[4] =
{0.5, 0.5, 0.5, 1.0};
fogMode = GL_EXP;
glFogi(GL_FOG_MODE, fogMode);
glFogfv(GL_FOG_COLOR, fogColor);
glFogf(GL_FOG_DENSITY, 0.35);
glHint(GL_FOG_HINT, GL_DONT_CARE);
glClearColor(0.5, 0.5, 0.5, 1.0);
}
}
void
renderRedTeapot(GLfloat x, GLfloat y, GLfloat z)
{
float mat[4];
glPushMatrix();
glTranslatef(x, y, z);
mat[0] = 0.1745;
mat[1] = 0.01175;
mat[2] = 0.01175;
mat[3] = 1.0;
glMaterialfv(GL_FRONT, GL_AMBIENT, mat);
mat[0] = 0.61424;
mat[1] = 0.04136;
mat[2] = 0.04136;
glMaterialfv(GL_FRONT, GL_DIFFUSE, mat);
mat[0] = 0.727811;
mat[1] = 0.626959;
mat[2] = 0.626959;
glMaterialfv(GL_FRONT, GL_SPECULAR, mat);
glMaterialf(GL_FRONT, GL_SHININESS, 0.6 * 128.0);
glutSolidTeapot(1.0);
glPopMatrix();
}
/* display() draws 5 teapots at different z positions.
*/
void
display(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
renderRedTeapot(-4.0, -0.5, -1.0);
renderRedTeapot(-2.0, -0.5, -2.0);
renderRedTeapot(0.0, -0.5, -3.0);
renderRedTeapot(2.0, -0.5, -4.0);
renderRedTeapot(4.0, -0.5, -5.0);
glFlush();
}
void
myReshape(int w, int h)
{
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (w <= (h * 3))
glOrtho(-6.0, 6.0, -2.0 * ((GLfloat) h * 3) / (GLfloat) w,
2.0 * ((GLfloat) h * 3) / (GLfloat) w, 0.0, 10.0);
else
glOrtho(-6.0 * (GLfloat) w / ((GLfloat) h * 3),
6.0 * (GLfloat) w / ((GLfloat) h * 3), -2.0, 2.0, 0.0, 10.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
static void
key(unsigned char k, int x, int y)
{
switch (k) {
case 27: /* Escape */
exit(0);
break;
default:
return;
}
glutPostRedisplay();
}
/* Main Loop
* Open window with initial window size, title bar,
* RGBA display mode, depth buffer, and handle input events.
*/
int
main(int argc, char **argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(450, 150);
glutCreateWindow(argv[0]);
myinit();
glutReshapeFunc(myReshape);
glutDisplayFunc(display);
glutCreateMenu(selectFog);
glutAddMenuEntry("Fog EXP", GL_EXP);
glutAddMenuEntry("Fog EXP2", /*GL_EXP2*/ 0xffff);
glutAddMenuEntry("Fog LINEAR", GL_LINEAR);
glutAddMenuEntry("Quit", 0);
glutAttachMenu(GLUT_RIGHT_BUTTON);
glutKeyboardFunc(key);
glutMainLoop();
return 0; /* ANSI C requires main to return int. */
}
|
