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

int main()
{

  static int width = 100;
  static int height = 100;

  Display* DisplayId = XOpenDisplay(NULL);
  if(!DisplayId)
    {
    printf("couldn't open display\n");
    return 1;
    }

  XSynchronize(DisplayId, true);

  static int    attributes[50];
  int index = 0;
  attributes[index++] = GLX_DRAWABLE_TYPE;
  attributes[index++] = GLX_PBUFFER_BIT;
  attributes[index++] = GLX_RENDER_TYPE;
  attributes[index++] = GLX_RGBA_BIT;
  attributes[index++] = GLX_RED_SIZE;
  attributes[index++] = 1;
  attributes[index++] = GLX_GREEN_SIZE;
  attributes[index++] = 1;
  attributes[index++] = GLX_BLUE_SIZE;
  attributes[index++] = 1;
  attributes[index++] = GLX_DEPTH_SIZE;
  attributes[index++] = 1;
  attributes[index++] = None;

  int numfb;
  GLXFBConfig* fb = glXChooseFBConfig(DisplayId, DefaultScreen(DisplayId),
                                      attributes, &numfb);
  
  if(!fb)
    {
    printf("couldn't find FBConfig\n");
    return 1;
    }

  GLXContext ContextId = glXCreateNewContext(DisplayId, fb[0],
                                             GLX_RGBA_TYPE,
                                             NULL, true);

  if(!ContextId)
    {
    printf("couldn't make context\n");
    return 1;
    }

  int pbuffer_atts [] = {
      GLX_PBUFFER_WIDTH, width,
      GLX_PBUFFER_HEIGHT, height,
      0
      };

  GLXPbuffer Pbuffer = glXCreatePbuffer(DisplayId, fb[0], pbuffer_atts);

  if(Pbuffer == None)
    {
    printf("couldn't make pbuffer\n");
    return 1;
    }

  XFree(fb);

  glXMakeCurrent(DisplayId, Pbuffer, ContextId);

  // sometimes get an X error here from Mesa w/ DRI
  glXDestroyPbuffer(DisplayId, Pbuffer);

  glXDestroyContext(DisplayId, ContextId);

  return 0;
}