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

#define WINDSIZEX 100
#define WINDSIZEY 100

void Draw()
{

   GLint size =64;
   GLint trueSize = size+2;

      glBegin(GL_POLYGON);
      glTexCoord2f(-1.0/(GLfloat)size, -1.0/(GLfloat)size);
      glVertex2i(0, 0);
      glTexCoord2f(-1.0/(GLfloat)size, 1.0+1.0/(GLfloat)size);
      glVertex2i(0, trueSize);
      glTexCoord2f(1.0+1.0/(GLfloat)size, 1.0+1.0/(GLfloat)size);
      glVertex2i(trueSize, trueSize);
      glTexCoord2f(1.0+1.0/(GLfloat)size, -1.0/(GLfloat)size);
      glVertex2i(trueSize, 0);
      glEnd();
}

void init(void)
{
   glClearColor(1.0, 1.0, 1.0, 1.0);
   glDisable(GL_DITHER);
   glBlendFunc (GL_ZERO, GL_SRC_ALPHA);

   glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

   glTexParameterf(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
   glTexParameterf(GL_TEXTURE_1D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);

   glTexParameterf(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   glTexParameterf(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
}

static void test(void)
{    
   GLfloat buf[4];
   GLfloat bcolor [] = {0.5, 0.8, 0.6, 0.4 };
   GLfloat *texBuf, *readBuf;
   int i;

   texBuf = (GLfloat *)malloc(66*66*4*sizeof(GLfloat));   
   readBuf = (GLfloat *)malloc(66*66*4*sizeof(GLfloat));   
   for (i = 0; i < 64*64; i++) {
      texBuf[i*4] = 0.6;
      texBuf[i*4+1] = 0.7;
      texBuf[i*4+2] = 0.6;
      texBuf[i*4+3] = 0.6;
   }

   glEnable(GL_TEXTURE_1D);

   glTexImage1D(GL_TEXTURE_1D, 0, GL_LUMINANCE,
	 64, 0, GL_RGBA, GL_FLOAT, (unsigned char *)texBuf);
   glTexParameterfv(GL_TEXTURE_1D, GL_TEXTURE_BORDER_COLOR, bcolor);

   Draw();
   glReadPixels(0, 0, 66, 66, GL_RGB, GL_FLOAT, readBuf);
   printf ("pixels at border: %f %f %f \n", readBuf[0], readBuf[1], readBuf[2]);
   printf ("it should be: 0.5, 0.5, 0.5\n");
}

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; 
}