tri-fog.c revision 32001f49 
1/*
2 * Copyright (c) 1991, 1992, 1993 Silicon Graphics, Inc.
3 *
4 * Permission to use, copy, modify, distribute, and sell this software and
5 * its documentation for any purpose is hereby granted without fee, provided
6 * that (i) the above copyright notices and this permission notice appear in
7 * all copies of the software and related documentation, and (ii) the name of
8 * Silicon Graphics may not be used in any advertising or
9 * publicity relating to the software without the specific, prior written
10 * permission of Silicon Graphics.
11 *
12 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF
13 * ANY KIND,
14 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
15 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
16 *
17 * IN NO EVENT SHALL SILICON GRAPHICS BE LIABLE FOR
18 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
19 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
20 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
21 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
22 * OF THIS SOFTWARE.
23 */
24
25#include <stdio.h>
26#include <string.h>
27#include <stdlib.h>
28#include "glut_wrap.h"
29
30
31#define CI_OFFSET_1 16
32#define CI_OFFSET_2 32
33
34GLint Width = 250, Height = 250;
35
36GLenum doubleBuffer;
37
38static void Init(void)
39{
40   fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
41   fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
42   fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
43   fflush(stderr);
44
45    glClearColor(0.0, 0.0, 1.0, 0.0);
46
47    glEnable(GL_FOG);
48    glFogi(GL_FOG_MODE, GL_LINEAR);
49    glFogf(GL_FOG_START, 25);
50    glFogf(GL_FOG_END, 35);
51#if 0
52    glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
53    glEnable (GL_BLEND);
54#endif
55}
56
57static void Reshape(int width, int height)
58{
59
60    glViewport(0, 0, (GLint)width, (GLint)height);
61
62    glMatrixMode(GL_PROJECTION);
63    glLoadIdentity();
64    glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
65    glMatrixMode(GL_MODELVIEW);
66}
67
68static void Key(unsigned char key, int x, int y)
69{
70
71    switch (key) {
72      case 27:
73	exit(1);
74      default:
75	break;
76    }
77
78    glutPostRedisplay();
79}
80
81static void Draw(void)
82{
83   glClear(GL_COLOR_BUFFER_BIT);
84
85   glEnable(GL_FOG);
86
87   glBegin(GL_TRIANGLES);
88   glColor3f(1,1,1);
89   glVertex3f( 0.9, -0.9, -30.0);
90   glColor3f(1,1,1);
91   glVertex3f( 0.9,  0.9, -30.0);
92   glColor3f(1,1,1);
93   glVertex3f(-0.9,  0.0, -40.0);
94   glEnd();
95
96#if 0
97   glBegin(GL_TRIANGLES);
98   glColor3f(0,0,.7);
99   glVertex3f(-0.9, -0.9, -30.0);
100   glColor3f(.8,0,0);
101   glVertex3f(-0.9,  0.9, -30.0);
102   glColor3f(0,.9,0);
103   glVertex3f( 0.9,  0.0, -30.0);
104   glEnd();
105#endif
106
107   glDisable(GL_FOG);
108
109   glFlush();
110
111   if (doubleBuffer) {
112      glutSwapBuffers();
113   }
114}
115
116static GLenum Args(int argc, char **argv)
117{
118    GLint i;
119
120    doubleBuffer = GL_FALSE;
121
122    for (i = 1; i < argc; i++) {
123        if (strcmp(argv[i], "-sb") == 0) {
124	    doubleBuffer = GL_FALSE;
125	} else if (strcmp(argv[i], "-db") == 0) {
126	    doubleBuffer = GL_TRUE;
127	} else {
128	    fprintf(stderr, "%s (Bad option).\n", argv[i]);
129	    return GL_FALSE;
130	}
131    }
132    return GL_TRUE;
133}
134
135int main(int argc, char **argv)
136{
137    GLenum type;
138
139    glutInit(&argc, argv);
140
141    if (Args(argc, argv) == GL_FALSE) {
142	exit(1);
143    }
144
145    glutInitWindowPosition(100, 0); glutInitWindowSize(Width, Height);
146
147    type = GLUT_RGB;
148    type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
149    glutInitDisplayMode(type);
150
151    if (glutCreateWindow(*argv) == GL_FALSE) {
152	exit(1);
153    }
154
155    Init();
156
157    glutReshapeFunc(Reshape);
158    glutKeyboardFunc(Key);
159    glutDisplayFunc(Draw);
160    glutMainLoop();
161	return 0;
162}
163