#include "GL/glut.h"
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

#define WINDSIZEX 100
#define WINDSIZEY 100

#define TEXSIZE 64


static GLfloat buf1[3];               // Buffers for reading screen

static GLfloat *rgbRasPosTexture;

static GLuint  texImages;

static GLfloat mMap[] = {
    1.0, 0.0, 0.0, 0.0,
    0.0, 1.0, 0.0, 0.0,
    1.0, 1.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 1.0,
};

static GLfloat mScale[] = {
    1.0/64.0,      0.0, 0.0, 0.0,
    0.0,      1.0/64.0, 0.0, 0.0,
    0.0,           0.0, 0.0, 0.0,
    0.0,           0.0, 0.0, 1.0,
};

#define RASPOSX             (22)
#define RASPOSY             (36)

static void CreateRasterPosTexture(void)
{
   GLint   x, y;
   GLfloat *prgb = rgbRasPosTexture;

   for (y = 0; y < TEXSIZE; y++) {
      for (x = 0; x < TEXSIZE; x++) {
	 if ((x == RASPOSX)&&(y == 0)) {
	    *prgb++ = 0.0;
	    *prgb++ = 1.0;
	    *prgb++ = 0.0;
	 } else if ((x == RASPOSX)&&(y == RASPOSY)) {
	    *prgb++ = 1.0;
	    *prgb++ = 0.0;
	    *prgb++ = 0.0;
	 } else {
	    *prgb++ = 0.0;
	    *prgb++ = 0.0;
	    *prgb++ = 1.0;
	 }
      }
   }
}

void init()
{
   glDisable(GL_DITHER);

   glClearColor (0.0, 0.0, 0.0, 0.0);

   // Allocate memory for creating the ramp tecture
   rgbRasPosTexture = (GLfloat *)malloc(TEXSIZE*TEXSIZE*3*sizeof(GLfloat));

   glGenTextures(1, &texImages);     


   glBindTexture (GL_TEXTURE_2D, texImages);

   glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
   glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
   glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

   CreateRasterPosTexture ();
   glTexImage2D (GL_TEXTURE_2D, 0, GL_RGB, TEXSIZE, TEXSIZE,
	 0, GL_RGB, GL_FLOAT, rgbRasPosTexture);

   glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);

   glEnable (GL_TEXTURE_2D);

    glMatrixMode (GL_TEXTURE);
    glLoadIdentity ();
    glLoadMatrixf (mScale);
    glMultMatrixf (mMap);

}

long Test (GLint x1, GLint y1)
{
   glReadPixels(x1, y1, 1, 1, GL_RGB, GL_FLOAT, buf1);
   printf ("pixel color: %f %f %f\n", buf1[0], buf1[1], buf1[2]);
   return 0;
}

#define X1   4
#define Y1   4

void test(){
   GLubyte bitmap[] = {0xFF};
   glClear (GL_COLOR_BUFFER_BIT);

   glNewList (1, GL_COMPILE_AND_EXECUTE);
//   glNewList (1, GL_COMPILE);
   glBindTexture (GL_TEXTURE_2D, texImages);
   glTexCoord1d (22.0); 
   glRasterPos2f (X1 + 0.25, Y1 + 0.25);
   glBitmap (1, 1, 0.0, 0.0, 0.0, 0.0, bitmap);

   glEndList();
//   glCallList(1);
   Test (X1, Y1);
}

void display()
{
   glViewport(0, 0, WINDSIZEX, WINDSIZEY);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   gluOrtho2D(0, WINDSIZEY, 0, WINDSIZEX);
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();

   test();
}

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