Hi Jordi,

The lines of code in question seem fine as is.  This loop is simply stepping
along the time history of scans until it finds a scan that occurs after the
request begin time.  The next while loop in the function then continues
stepping along, until it steps past the end of the request.

The tutorial was in fact broken.  I've uploaded a new laser.bag file, and
updated the launch file snippets.

Thank for reporting your troubles with this tutorial.  If you are still
running into problems, please let me know.

Vijay

On Thu, May 27, 2010 at 9:22 AM, Jordi Pages
<jordi.pages@pal-robotics.com>wrote:

> Hi all,
>
>    I am trying to follow the tutorial
> laser_assembler/tutorials/HowToAssembleLaserScans<http://www.ros.org/wiki/laser_assembler/Tutorials/HowToAssembleLaserScans>and I can't achieve assembling several laser scans in a unique cloud of
> points. I am using rosplay to publish pre-recorded data from the bag file
> laser.bag that can be downloaded from ros webpage. I have been adding trace
> messages in base_assembler.h and I have the sensation that in the following
> portion of code in assembleScans callback function
>
>   while ( i < scan_hist_.size() && scan_hist_[i].header.stamp < req.begin
> )
>   {
>     i++ ;
>   }
>
> the right part of the while condition should be instead
>
> scan_hist_[i].header.stamp >= req.begin
>
> otherwise I get that no points are assembled because both start_index and
> past_end_index have the same value and none of the laser scans are selected.
>
> Can anybody check that it is actually a bug? Am I not executing correctly
> the laser pipeline?
>
> Thanks in adavance
>
> --
> Jordi Pages, PhD
> Researcher
> Pal Robotics S.L.
>
> Tel: +34.93.414.53.47
> Fax: +34.93.209.11.09
> C/ Pujades 77-79 4º 4ª 08005 Barcelona, Spain.
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