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

#define WINDSIZEX 100
#define WINDSIZEY 100

#define SIZEW 4
#define TSIZE 4

// Draw function used by many test casses
static void
DrawTex ()
{
  glBegin (GL_QUADS);
  glTexCoord3f (0.0, 0.0, 0);
  glVertex2i (0, 0);
  glTexCoord3f (1.0, 0.0, 0);
  glVertex2i (0, 1);
  glTexCoord3f (1.0, 1.0, 0);
  glVertex2i (SIZEW, 1);
  glTexCoord3f (0.0, 1.0, 0);
  glVertex2i (SIZEW, 0);
  glEnd ();
}

void
init (void)
{
  glClearColor (1, 1, 1, 1);
  glClear (GL_COLOR_BUFFER_BIT);
  glShadeModel (GL_FLAT);
  glDisable (GL_DITHER);
  glBlendFunc (GL_ZERO, GL_SRC_ALPHA);
}

static void
test (void)
{
  GLfloat *buf;
  char cmd1[1024] =
    "!!ARBfp1.0\nOUTPUT tempout = result.color;\nTEX  tempout.rb, fragment.texcoord.yxzw, texture, 1D;\n\nEND\n";
  GLuint programName;

  GLfloat texImage1D[TSIZE];
  int i;

  glTexParameteri (GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
  glTexParameteri (GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  glTexParameteri (GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP);

  //Make texture
  for (i = 0; i < TSIZE; i++)
    {
      texImage1D[i] = 0.6;	//random(0.0, 1.0);
    }

  glTexImage1D (GL_TEXTURE_1D, 0, GL_RGBA, TSIZE,
		0, GL_RGBA, GL_FLOAT, texImage1D);

///////////////////////////////

  glGenProgramsARB (1, &programName);
  // bind a program to the name
  glBindProgramARB (GL_FRAGMENT_PROGRAM_ARB, programName);
  ///////////////////////////////////////
  glProgramStringARB (GL_FRAGMENT_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
		      (GLint) strlen (cmd1), cmd1);
  if (glGetError () == GL_INVALID_OPERATION)
    {
      printf ("\nError loading program: check the error\n%s",
	      glGetString (GL_PROGRAM_ERROR_STRING_ARB));
      exit (1);
    }
  glEnable (GL_FRAGMENT_PROGRAM_ARB);

  glClear (GL_COLOR_BUFFER_BIT);
  DrawTex (GL_TEXTURE_1D);

  buf = (GLfloat *) malloc (TSIZE * sizeof (GLfloat) * 3);
  glReadPixels (0, 0, TSIZE, 1, GL_RGB, GL_FLOAT, buf);
  printf ("draw pixel at (0, 0): %f %f %f\n", buf[0], buf[1], buf[2]);
}

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

  test ();
}

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