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
  44     glClearColor(0.0, 0.0, 1.0, 0.0);
  45
  46     glEnable(GL_FOG);
  47     glFogi(GL_FOG_MODE, GL_LINEAR);
  48     glFogf(GL_FOG_START, 25);
  49     glFogf(GL_FOG_END, 35);
  50 #if 0
  51     glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  52     glEnable (GL_BLEND);
  53 #endif
  54 }
  55
  56 static void Reshape(int width, int height)
  57 {
  58
  59     glViewport(0, 0, (GLint)width, (GLint)height);
  60
  61     glMatrixMode(GL_PROJECTION);
  62     glLoadIdentity();
  63     glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  64     glMatrixMode(GL_MODELVIEW);
  65 }
  66
  67 static void Key(unsigned char key, int x, int y)
  68 {
  69
  70     switch (key) {
  71       case 27:
  72         exit(1);
  73       default:
  74         return;
  75     }
  76
  77     glutPostRedisplay();
  78 }
  79
  80 static void Draw(void)
  81 {
  82    glClear(GL_COLOR_BUFFER_BIT);
  83
  84    glEnable(GL_FOG);
  85
  86    glBegin(GL_TRIANGLES);
  87    glColor3f(1,1,1);
  88    glVertex3f( 0.9, -0.9, -30.0);
  89    glColor3f(1,1,1);
  90    glVertex3f( 0.9,  0.9, -30.0);
  91    glColor3f(1,1,1);
  92    glVertex3f(-0.9,  0.0, -40.0);
  93    glEnd();
  94
  95 #if 0
  96    glBegin(GL_TRIANGLES);
  97    glColor3f(0,0,.7);
  98    glVertex3f(-0.9, -0.9, -30.0);
  99    glColor3f(.8,0,0);
 100    glVertex3f(-0.9,  0.9, -30.0);
 101    glColor3f(0,.9,0);
 102    glVertex3f( 0.9,  0.0, -30.0);
 103    glEnd();
 104 #endif
 105
 106    glDisable(GL_FOG);
 107
 108    glFlush();
 109
 110    if (doubleBuffer) {
 111       glutSwapBuffers();
 112    }
 113 }
 114
 115 static GLenum Args(int argc, char **argv)
 116 {
 117     GLint i;
 118
 119     doubleBuffer = GL_FALSE;
 120
 121     for (i = 1; i < argc; i++) {
 122         if (strcmp(argv[i], "-sb") == 0) {
 123             doubleBuffer = GL_FALSE;
 124         } else if (strcmp(argv[i], "-db") == 0) {
 125             doubleBuffer = GL_TRUE;
 126         } else {
 127             fprintf(stderr, "%s (Bad option).\n", argv[i]);
 128             return GL_FALSE;
 129         }
 130     }
 131     return GL_TRUE;
 132 }
 133
 134 int main(int argc, char **argv)
 135 {
 136     GLenum type;
 137
 138     glutInit(&argc, argv);
 139
 140     if (Args(argc, argv) == GL_FALSE) {
 141         exit(1);
 142     }
 143
 144     glutInitWindowPosition(100, 0); glutInitWindowSize(Width, Height);
 145
 146     type = GLUT_RGB;
 147     type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
 148     glutInitDisplayMode(type);
 149
 150     if (glutCreateWindow("First Tri") == GL_FALSE) {
 151         exit(1);
 152     }
 153
 154     Init();
 155
 156     glutReshapeFunc(Reshape);
 157     glutKeyboardFunc(Key);
 158     glutDisplayFunc(Draw);
 159     glutMainLoop();
 160         return 0;
 161 }