progs/trivial/tri-fog.c

   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 <GL/glut.h>
  29
  30
  31 #define CI_OFFSET_1 16
  32 #define CI_OFFSET_2 32
  33
  34 GLint Width = 250, Height = 250;
  35
  36 GLenum doubleBuffer;
  37
  38 static 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
  57 static 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
  68 static void Key(unsigned char key, int x, int y)
  69 {
  70
  71     switch (key) {
  72       case 27:
  73         exit(1);
  74       default:
  75         return;
  76     }
  77
  78     glutPostRedisplay();
  79 }
  80
  81 static 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
 116 static 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
 135 int 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 }