Introduction

As in human soccer, a match is played without interruptions from outside the field. So nobody (and no application) except the players and the referee can influence and/or control the match. However, it would be very useful if you could have more control over the game while developing player-clients. For instance, the possibility to perform training sessions in which a certain action, such as dribbling, is tested in an automated way gives you the opportunity to apply machine learning methods.

Therefore, a privileged client called the coach-client has been introduced. The coach-client has the following capabilities:

• It can control the play-mode.
• It can broadcast audio messages. Such a message can consist of a command or some information intended for one or more of the player-clients. Its meaning (and interpretation) is user-defined.
• It can move an object (any player or the ball) to any location on the field irrespective of the current play-mode.
• It can get information about positions of all the (movable) objects on the field.