When does it react?

BP2 does react to MIDI input provided that (1) it is in the appropriate format, i.e. the message has been declared in the "Interaction" window ("-in.<filename>" file), and (2) both the "Interactive (use input)" and "Use MIDI in/out" buttons on the lower "Settings" dialog are checked (see Fig.24).

The status of these buttons is saved and loaded along with "-se.<filename>" settings files. Each time a project, grammar or data is loaded, their status might therefore change. Also make sure that a file has been loaded to the "Interaction" window, or load it manually if necessary: its name will be inserted on top of the "Grammar" and "Data" windows, so that it may automatically be loaded next time you start the project.

A third condition for BP2 to react to MIDI input messages is that it has free time. Messages are stacked into the MIDI input buffer waiting for BP2 to read them, which it does as often as possible. A delay in the response may be caused by the fact that BP2 was engaged on some more urgent task.

Apart from launching scripts, many parameters controlling BP2's operation may be directly modified via the MIDI input, as demonstrated below.