xref: /xsrc/external/mit/mesa-demos/dist/src/trivial/point-sprite.c

/*
 * Copyright (c) 1991, 1992, 1993 Silicon Graphics, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software and
 * its documentation for any purpose is hereby granted without fee, provided
 * that (i) the above copyright notices and this permission notice appear in
 * all copies of the software and related documentation, and (ii) the name of
 * Silicon Graphics may not be used in any advertising or
 * publicity relating to the software without the specific, prior written
 * permission of Silicon Graphics.
 *
 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF
 * ANY KIND,
 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
 *
 * IN NO EVENT SHALL SILICON GRAPHICS BE LIABLE FOR
 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <GL/glew.h>
#include "glut_wrap.h"


static void
Init(void)
{
   fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
   fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
   fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
   fflush(stderr);

   if (!glutExtensionSupported("GL_ARB_point_sprite")) {
      printf("GL_ARB_point_sprite not supported\n");
      exit(1);
   }

#define SIZE 16
   {
      GLubyte tex2d[SIZE][SIZE][3];
      GLint s, t;

      for (s = 0; s < SIZE; s++) {
         for (t = 0; t < SIZE; t++) {
#if 1
            tex2d[t][s][0] = (s < SIZE / 2) ? 0 : 255;
            tex2d[t][s][1] = (t < SIZE / 2) ? 0 : 255;
            tex2d[t][s][2] = 0;
#else
            tex2d[t][s][0] = s * 255 / (SIZE - 1);
            tex2d[t][s][1] = t * 255 / (SIZE - 1);
            tex2d[t][s][2] = 0;
#endif
         }
      }

      glTexEnvi(GL_POINT_SPRITE_ARB, GL_COORD_REPLACE_ARB, GL_TRUE);
      glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
      glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_R, GL_REPEAT);
      glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
      glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

      glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
      glTexImage2D(GL_TEXTURE_2D, 0, 3, SIZE, SIZE, 0,
                   GL_RGB, GL_UNSIGNED_BYTE, tex2d);
      glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
      glEnable(GL_TEXTURE_2D);
   }

   glEnable(GL_POINT_SPRITE);

   glClearColor(0.0, 0.0, 1.0, 0.0);
}


static void
Reshape(int width, int height)
{
   glViewport(0, 0, (GLint) width, (GLint) height);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
   glMatrixMode(GL_MODELVIEW);
}


static void
Key(unsigned char key, int x, int y)
{
   if (key == 27)
      exit(1);

   glutPostRedisplay();
}


static void
Draw(void)
{
   glClear(GL_COLOR_BUFFER_BIT);

   glPointSize(32.0);

   glBegin(GL_POINTS);
   glColor3f(1, 1, 1);
   glVertex3f(0.0, 0.0, -30.0);
   glEnd();

   glutSwapBuffers();
}


int
main(int argc, char **argv)
{
   glutInit(&argc, argv);
   glutInitWindowSize(250, 250);
   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
   if (glutCreateWindow(*argv) == GL_FALSE) {
      exit(1);
   }
   Init();
   glutReshapeFunc(Reshape);
   glutKeyboardFunc(Key);
   glutDisplayFunc(Draw);
   glutMainLoop();
   return 0;
}