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

#define WINDSIZEX 100
#define WINDSIZEY 100


int useFramebuffer = 0;
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);

    // Check if GL_EXT_framebuffer_object is supported
    if (!strstr (glGetString (GL_EXTENSIONS), "GL_EXT_framebuffer_object"))
    {
        printf ("GL_EXT_framebuffer_object is not supported\n");
	exit(0);
    }
    else
    {
        printf ("GL_EXT_framebuffer_object is supported\n");
    }
}


static void
test (void)
{
    GLuint fbs[1];
    GLuint textures[1];
    int i, j;
    GLint retVal;

    glGenTextures(1, textures);
    glBindTexture(GL_TEXTURE_2D, textures[0]);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB,
                                  128, 128,
                      0, GL_RGB, GL_FLOAT, 0 );

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 1);
    glTexImage2D(GL_TEXTURE_2D, 1, GL_RGB,
                                  128, 128,
                      0, GL_RGB, GL_FLOAT, 0 );

    glGenFramebuffersEXT (1, fbs);
    glBindFramebufferEXT (GL_FRAMEBUFFER_EXT, fbs[0]);
    glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT,
				GL_COLOR_ATTACHMENT0_EXT,
				GL_TEXTURE_2D,
				textures[0], 1);
    glGetFramebufferAttachmentParameterivEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
					     GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL_EXT,
					     &retVal);

    if (retVal != 1)
    {
	printf("retVal = %d, should be 1\n", retVal);
    }
}

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;

}