void
pp_callback (const pcl::visualization::PointPickingEvent& event, void* cookie)
{
  int idx = event.getPointIndex ();
  if (idx == -1)
    return;

  if (!cloud)
  {
    cloud = *reinterpret_cast<pcl::PCLPointCloud2::Ptr*> (cookie);
    xyzcloud.reset (new pcl::PointCloud<pcl::PointXYZ>);
    pcl::fromPCLPointCloud2 (*cloud, *xyzcloud);
    search.setInputCloud (xyzcloud);
  }
  // Return the correct index in the cloud instead of the index on the screen
  std::vector<int> indices (1);
  std::vector<float> distances (1);

  // Because VTK/OpenGL stores data without NaN, we lose the 1-1 correspondence, so we must search for the real point
  pcl::PointXYZ picked_pt;
  event.getPoint (picked_pt.x, picked_pt.y, picked_pt.z);
  //TODO: Look into this.
  search.nearestKSearch (picked_pt, 1, indices, distances);

  PCL_INFO ("Point index picked: %d (real: %d) - [%f, %f, %f]\n", idx, indices[0], picked_pt.x, picked_pt.y, picked_pt.z);

  idx = indices[0];
  // If two points were selected, draw an arrow between them
  pcl::PointXYZ p1, p2;
  if (event.getPoints (p1.x, p1.y, p1.z, p2.x, p2.y, p2.z) && p)
  {
    std::stringstream ss;
    ss << p1 << p2;
    p->addArrow<pcl::PointXYZ, pcl::PointXYZ> (p1, p2, 1.0, 1.0, 1.0, ss.str ());
    return;
  }

  // Else, if a single point has been selected
  std::stringstream ss;
  ss << idx;
  // Get the cloud's fields
  for (size_t i = 0; i < cloud->fields.size (); ++i)
  {
    if (!isMultiDimensionalFeatureField (cloud->fields[i]))
      continue;
    PCL_INFO ("Multidimensional field found: %s\n", cloud->fields[i].name.c_str ());
#if VTK_MAJOR_VERSION==6 || (VTK_MAJOR_VERSION==5 && VTK_MINOR_VERSION>6)
    ph_global.addFeatureHistogram (*cloud, cloud->fields[i].name, idx, ss.str ());
    ph_global.renderOnce ();
#endif
  }
  if (p)
  {
    pcl::PointXYZ pos;
    event.getPoint (pos.x, pos.y, pos.z);
    p->addText3D<pcl::PointXYZ> (ss.str (), pos, 0.0005, 1.0, 1.0, 1.0, ss.str ());
  }
  
}
void FindPickedPoint(const pcl::visualization::PointPickingEvent& event) {
	int idx = event.getPointIndex ();
	if (idx == -1)
	{
		std::cout << "Invalid pick!\n;";
		return;
	}
	search.setInputCloud(build_cloud_accurate_plane);

	// Return the correct index in the cloud instead of the index on the screen
	std::vector<int> indices (1);
	std::vector<float> distances (1);

	// Because VTK/OpenGL stores data without NaN, we lose the 1-1 correspondence, so we must search for the real point
	pcl::PointXYZ picked_pt;
	event.getPoint (picked_pt.x, picked_pt.y, picked_pt.z);
	search.nearestKSearch (picked_pt, 1, indices, distances);
	picked_points.push_back(picked_pt);
}