pcl to tf - example for pcl::transformPointCloud

edit

I am looking for a working example for translating a pointcloud to tf. Here is my example based on the examples here. pcl_ros tutorials (http://wiki.ros.org/pcl_ros#CA-1e7f8563c53a97f77516b3fe5ea24f4b33d237de_3)

typedef pcl::PointCloud<pcl::PointXYZ> PointCloud;

ros::Publisher tf_pub;
tf::TransformListener *tf_listener; 

void callback(const PointCloud::ConstPtr& pcl_in)
{

  PointCloud pcl_out;

  tf_listener->waitForTransform("/world", (*pcl_in).header.frame_id, (*pcl_in).header.stamp, ros::Duration(5.0));
  pcl_ros::transformPointCloud("/world", *pcl_in, pcl_out, *tf_listener);
  tf_pub.publish(pcl_out);

  printf ("Cloud: width = %d, height = %d\n", pcl_in->width, pcl_in->height);
  BOOST_FOREACH (const pcl::PointXYZ& pt, pcl_in->points)
    printf ("\t(%f, %f, %f)\n", pt.x, pt.y, pt.z);
}

int main(int argc, char** argv)
{
  ros::init(argc, argv, "sub_pcl");
  ros::NodeHandle nh;
  ros::Subscriber sub = nh.subscribe<PointCloud>("points2", 1, callback);
  tf_pub = nh.advertise<PointCloud> ("tf_points2", 1);

  tf_listener    = new tf::TransformListener();

  ros::spin();
  //delete tf_listener; 
  //return 0; 
}

this resumes in the following error.

[ERROR] [1381659561.691872448]: Frame id /pcl does not exist! Frames (3): Frame /world_marker exists with parent /world.
Frame /world exists with parent NO_PARENT.

the frame_id /pcl exists. rxgraph show that is all connected and well.

anybody there who can tell me what i'm doing wrong or maybe has a working example for me?

update: after looking around and trying a lot, i didn't find a working example anyway. the above code is not what i'am searching for. i was on the wrong lane, by googling to the theme pcl to tf.

i was looking for an example for maybe an /world frame and the /pcl frame from pcl_ros tutorial above. must i transform any point of the pointcloud or ...??? don't no what to do.

at the end, i only want a /world -> /camera -> /pcl tf chain for the ardrone. but stick in the pcl to tf thing and didn't come further :(

anybody out there who can help me at this point.