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