[robocup-legged] Re: Game controller backchannel format

[William Uther]

On 13/05/2006, at 3:29 PM, Joel.Fenwick at student.griffith.edu.au wrote:
> Hi Will,
>    Is the format of the messages from the robots back to the  
> gamecontroller documented anywhere (other than in the source)? We  
> are not running the GameController handler object on our dogs so  
> adapting to new versions/features is not a matter of dropping a  
> replacement version in without changes.
>
>
> Thanks
> Joel Fenwick
> Mi-Pal

Hi Joel,
   I hope you don't mind that I've CC'd the mailing list in this  
reply just in case anyone else is wondering the same thing.

   Firstly, the packets from the robot to the GameController are not  
required.  So you can feel free not to implement them if you don't  
want to.  (But, you are NOT allowed to penalise other team's robots  
using the interface.)

   The return packet is not properly documented.  It is defined in  
the same header as the packet to the robot: RoboCupGameControlData.h  
which contains the RoboCupGameControlReturnData structure  
definition.  The header and version fields should contain the  
constants defined in the header file (the ones for the return packet,  
not the ones for the main packet).  The team and player fields should  
contain the team and player number.  The message should contain one  
of the constants defined in the header file - one for penalise and  
one for unpenalise.
   The return packet is simply broadcast once on the same UDP port  
used by the GameController.  If it gets dropped, then the dog will  
unpenalise the next time it gets a game-controller packet.  You then  
re-penalise it and it will sent its manual penalise packet again.

   It is a stupidly simple protocol, but seems to work OK, so I  
didn't both implementing anything more complex.

Be well,

Will            :-}

--
Dr William Uther                           National ICT Australia
Phone: +61 2 8306 0424               Computer Science and Engineering
Email: william.uther at nicta.com.au      University of New South Wales
Email: willu at cse.unsw.edu.au                  Sydney, Australia

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