Page 183 - Hacking Roomba

164 Part II — Fun Things to Do

The playMidiNote() method uses no Java MIDI classes, and it can be called like any other
method. This is the manner in which a port to a non–OS X platform would occur.

Listing 8-5: playMidiNote() in RoombaCommPanel

public void playMidiNote(int notenum, int velocity) {
updateDisplay(“play note: “+notenum+”,”+velocity+”\n”);
if( !roombacomm.connected() ) return;

if( notenum >= 31 ) { // G and above
if( velocity == 0 ) return;
if( velocity < 4 ) velocity = 4; // has problems at lower
durations
else
velocity = velocity/2;
roombacomm.playNote(notenum, velocity);
}
else if( notenum == 24 ) { // C
roombacomm.vacuum( !(velocity==0) );
}
else if( notenum == 25 ) { // C#
boolean lon = (velocity!=0);
int inten = (lon) ? 255:128; // either full bright or half
bright
roombacomm.setLEDs(lon,lon,lon,lon,lon,lon, velocity*2,
inten);
}
else if( notenum == 28 ) { // E
if( velocity!=0 ) roombacomm.spinLeftAt(velocity*2);
else roombacomm.stop();
}
else if( notenum == 29 ) { // F
if( velocity!=0 ) roombacomm.spinRightAt(velocity*2);
else roombacomm.stop();
}
}

Working with Core MIDI

In the Mac OS X Core MIDI API, to participate in MIDI communications, you first create a
MIDIClient object by calling new MIDIClient(), passing in the name you want your client
to be called. Once you have a MIDIClient, you can create a virtual MIDI interface by calling
destinationCreate() on it. This is shown in the setupMidi() method in Listing 8-6.
Listing 8-6 shows the MIDI handling methods of RoombaMidi.java.