progs/trivial/point-sprite.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    fflush(stderr);
  43
  44
  45 #define SIZE 16
  46    {
  47       GLubyte tex2d[SIZE][SIZE][3];
  48       GLint s, t;
  49
  50       for (s = 0; s < SIZE; s++) {
  51          for (t = 0; t < SIZE; t++) {
  52 #if 1
  53             tex2d[t][s][0] = (s < SIZE/2) ? 0 : 255;
  54             tex2d[t][s][1] = (t < SIZE/2) ? 0 : 255;
  55             tex2d[t][s][2] = 0;
  56 #else
  57             tex2d[t][s][0] = s*255/(SIZE-1);
  58             tex2d[t][s][1] = t*255/(SIZE-1);
  59             tex2d[t][s][2] = 0;
  60 #endif
  61          }
  62       }
  63
  64       glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
  65       glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_R, GL_REPEAT);
  66       glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  67       glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
  68
  69       glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  70       glTexImage2D(GL_TEXTURE_2D, 0, 3, SIZE, SIZE, 0,
  71                    GL_RGB, GL_UNSIGNED_BYTE, tex2d);
  72       glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
  73       glEnable(GL_TEXTURE_2D);
  74    }
  75
  76    glEnable(GL_POINT_SPRITE);
  77
  78     glClearColor(0.0, 0.0, 1.0, 0.0);
  79 }
  80
  81 static void Reshape(int width, int height)
  82 {
  83
  84     glViewport(0, 0, (GLint)width, (GLint)height);
  85
  86     glMatrixMode(GL_PROJECTION);
  87     glLoadIdentity();
  88     glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  89     glMatrixMode(GL_MODELVIEW);
  90 }
  91
  92 static void Key(unsigned char key, int x, int y)
  93 {
  94
  95     switch (key) {
  96       case 27:
  97         exit(1);
  98       default:
  99         break;
 100     }
 101
 102     glutPostRedisplay();
 103 }
 104
 105 static void Draw(void)
 106 {
 107    glClear(GL_COLOR_BUFFER_BIT);
 108
 109    glPointSize(16.0);
 110
 111    glBegin(GL_POINTS);
 112    glColor3f(1,0,0);
 113    glVertex3f( 0.6, -0.6, -30.0);
 114    glColor3f(1,1,0);
 115    glVertex3f( 0.6,  0.6, -30.0);
 116    glColor3f(1,0,1);
 117    glVertex3f(-0.6,  0.6, -30.0);
 118    glColor3f(0,1,1);
 119    glVertex3f(-0.6,  -0.6, -30.0);
 120    glEnd();
 121
 122    glFlush();
 123
 124    if (doubleBuffer) {
 125       glutSwapBuffers();
 126    }
 127 }
 128
 129 static GLenum Args(int argc, char **argv)
 130 {
 131     GLint i;
 132
 133     doubleBuffer = GL_FALSE;
 134
 135     for (i = 1; i < argc; i++) {
 136         if (strcmp(argv[i], "-sb") == 0) {
 137             doubleBuffer = GL_FALSE;
 138         } else if (strcmp(argv[i], "-db") == 0) {
 139             doubleBuffer = GL_TRUE;
 140         } else {
 141             fprintf(stderr, "%s (Bad option).\n", argv[i]);
 142             return GL_FALSE;
 143         }
 144     }
 145     return GL_TRUE;
 146 }
 147
 148 int main(int argc, char **argv)
 149 {
 150     GLenum type;
 151
 152     glutInit(&argc, argv);
 153
 154     if (Args(argc, argv) == GL_FALSE) {
 155         exit(1);
 156     }
 157
 158     glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250);
 159
 160     type = GLUT_RGB;
 161     type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
 162     glutInitDisplayMode(type);
 163
 164     if (glutCreateWindow(*argv) == GL_FALSE) {
 165         exit(1);
 166     }
 167
 168     Init();
 169
 170     glutReshapeFunc(Reshape);
 171     glutKeyboardFunc(Key);
 172     glutDisplayFunc(Draw);
 173     glutMainLoop();
 174         return 0;
 175 }