#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>

#define WINDSIZEX 100
#define WINDSIZEY 100


static GLubyte bitmap[8 * 8 / 8];


void
init (void)
{
  int i;
  GLfloat white[] = { 1.0, 1.0, 1.0, 1.0 };
  glClearColor (0.0, 0.0, 0.0, 1.0);
  glColor4fv (white);
  glDisable (GL_DITHER);
}


static void
test (void)
{
  int i, j;
  GLfloat red[] = { 0.0, 1.0, 0.0, 1.0 };
  GLfloat buf[3];


  for(i = 0; i < (sizeof (bitmap) / sizeof (bitmap[0])); i++){
    bitmap[i]=0xFF;
  }
  glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

  glClearColor (0.0, 0.0, 0.0, 1.0);
  glClear(GL_COLOR_BUFFER_BIT);

  glDrawBuffer(GL_NONE);

  glColor4fv (red);
  glRasterPos2f(0.25, 0.25);
  glBitmap (8, 8, 0.0, 0.0, 0.0, 0.0, bitmap);

  glReadPixels(0, 0, 1, 1, GL_RGB, GL_FLOAT, buf);
  printf("read back (0, 0) = [%f, %f, %f]\n", buf[0], buf[1], buf[2]);
  printf("should be [%f, %f, %f]\n", 0.0, 0.0, 0.0);

}

void
display (void)
{
  glMatrixMode (GL_PROJECTION);
  glLoadIdentity ();
  gluOrtho2D (0, WINDSIZEX, 0, WINDSIZEX);
  test ();
}

int
main (int argc, char **argv)
{
  glutInit (&argc, argv);
  glutInitDisplayMode (GLUT_SINGLE | GLUT_RGBA);
  glutInitWindowSize (WINDSIZEX, WINDSIZEY);
  glutInitWindowPosition (100, 100);
  glutCreateWindow (argv[0]);
  init ();
  glutDisplayFunc (display);
  glutMainLoop ();
  return 0;
}