Writing a Player interface

From The Player Project

Revision as of 18:20, 9 January 2010

A interface is a specification of how to interact with a certain class of robotic sensor, actuator, or algorithm. The interface defines the syntax and semantics of all messages that can be exchanged with entities in the same class.

To add a new interface create a new file in /libplayercore/interfaces/ directory. The file name should be

<interface number>_<interface name>.def

for example 006_laser.def

The interface number should be padded to three digits to aid sorting. New interfaces should use the next free interface code rather than filling in gaps. This is to avoid confusion with old removed interfaces.

In the file you should have:

* a description block that contains a description of the interface 
  for the documentation
* a set of message blocks that define the interfaces messages
  these are structured as 
    message { TYPE, SUBTYPE, SUBTYPE_CODE, DATA_TYPE };
* the data types for your interface in standard C code

The best bet is to have a look at some of the other interfaces and copy what they have done

When modifying an interface try to avoid renumbering the subtype codes. If you remove a subtype just leave a gap, this will aid in version compatibility.