progs/trivial/clear-random.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
  35 GLenum doubleBuffer;
  36
  37 static void Init(void)
  38 {
  39    fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
  40    fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
  41    fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
  42
  43 }
  44
  45 static void Reshape(int width, int height)
  46 {
  47
  48     glViewport(0, 0, (GLint)width, (GLint)height);
  49
  50     glMatrixMode(GL_PROJECTION);
  51     glLoadIdentity();
  52     glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  53     glMatrixMode(GL_MODELVIEW);
  54 }
  55
  56 static void Key(unsigned char key, int x, int y)
  57 {
  58
  59     switch (key) {
  60       case 27:
  61         exit(0);
  62       default:
  63         return;
  64     }
  65
  66     glutPostRedisplay();
  67 }
  68
  69 static void Draw(void)
  70 {
  71     glClearColor(
  72        rand() / (float)RAND_MAX,
  73        rand() / (float)RAND_MAX,
  74        rand() / (float)RAND_MAX,
  75        0.0);
  76
  77    glClear(GL_COLOR_BUFFER_BIT);
  78    glFlush();
  79
  80    if (doubleBuffer) {
  81       glutSwapBuffers();
  82    }
  83 }
  84
  85 static GLenum Args(int argc, char **argv)
  86 {
  87     GLint i;
  88
  89     doubleBuffer = GL_FALSE;
  90
  91     for (i = 1; i < argc; i++) {
  92         if (strcmp(argv[i], "-sb") == 0) {
  93             doubleBuffer = GL_FALSE;
  94         } else if (strcmp(argv[i], "-db") == 0) {
  95             doubleBuffer = GL_TRUE;
  96         } else {
  97             fprintf(stderr, "%s (Bad option).\n", argv[i]);
  98             return GL_FALSE;
  99         }
 100     }
 101     return GL_TRUE;
 102 }
 103
 104 int main(int argc, char **argv)
 105 {
 106     GLenum type;
 107
 108     glutInit(&argc, argv);
 109
 110     if (Args(argc, argv) == GL_FALSE) {
 111         exit(1);
 112     }
 113
 114     glutInitWindowPosition(0, 0);
 115     glutInitWindowSize( 256, 256);
 116
 117     type = GLUT_RGB | GLUT_ALPHA;
 118     type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
 119     glutInitDisplayMode(type);
 120
 121     if (glutCreateWindow(*argv) == GL_FALSE) {
 122         exit(1);
 123     }
 124
 125     Init();
 126
 127     glutReshapeFunc(Reshape);
 128     glutKeyboardFunc(Key);
 129     glutDisplayFunc(Draw);
 130     glutMainLoop();
 131     return 0;
 132 }