#include <stdlib.h>
#include <stdio.h>

#include <GL/gl.h>
#include <GL/glx.h>

#include <X11/Xlib-xcb.h>
#include <X11/Xproto.h>
#include <X11/extensions/Xcomposite.h>


int main() {
	Display* dpy = XOpenDisplay(NULL);
	XWindowAttributes attrib;
  XVisualInfo		 templ;
  XVisualInfo		 *visinfo;
  Colormap colormap;
  GLXFBConfig		 *fbConfigs;
  int value, nvisinfo;
  Window root = XRootWindow (dpy, 0);

	if (!XGetWindowAttributes (dpy, root, &attrib))
		return 1;

	templ.visualid = XVisualIDFromVisual(attrib.visual);
	printf("Using visual 0x%x\n", templ.visualid);
		
	visinfo = XGetVisualInfo(dpy, VisualIDMask, &templ, &nvisinfo);
	if (!nvisinfo) {
		printf("Couldn't get visual info for default visual\n");
		return 2;
	}

	glXGetConfig (dpy, visinfo, GLX_USE_GL, &value);
	if (!value) 	{
		printf("Root visual is not a GL visual\n");
		XFree (visinfo);
		return 3;
	}

	glXGetConfig (dpy, visinfo, GLX_DOUBLEBUFFER, &value);
	if (!value) {
		printf("Root visual is not a double buffered GL visual\n");
		XFree (visinfo);
		return 4;
	}
	
	return 0;
}