Midishare and jMusic
Midishare is an open
source MIDI input and output library developed by Grame in
France. At the moment, Midishare is perhaps the best option for
realtime MIDI in jMusic. As a result the jmms (jmusic to
midishare) package has been created in jMusic, so that it is easy to
utilise the features of Midishare from jMusic.
For information on downloading and installing
the Midishare development kit see the midishare website.
Both the readme and setup.html have important information on the way
midishare works. The easy way is to just copy the relevant
drivers etc into your working directory (rather than putting them in
any system folder). You will also need to put grame.jar in your
class path to access the midishare libraries.
Once you have that done that, make sure you
test the Midishare applications to see if they are working on their own.
Once Midishare is working, it is a relatively
simple step to get it working with jMusic. Just to get some sound
happening, you can download this test file which should emit c4 (middle
c) every quarter of a second.
Click here to view
source.
Lets have a closer look.
import jmms.*;
import jm.music.data.*;
public class MPlayerTester extends MPlayer {
public
MPlayerTester() {
}
public Score nextScore() {
System.out.println("making
score");
return new Score(new Part(new Phrase(new
Note(60, 0.25, 120))));
}
public
static void main(String[] args) {
MPlayerTester
jt = new MPlayerTester();
jt.go();
}
}
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Pretty simple huh?
The important method here is the nextScore() method. You see how
it returns a "Score" object? That score object is taken away and
played via Midishare every 0.25 of a beat. So, just say you want
d4 to play instead of c4, can you guess what bit to change?
Answer is below (62 instead of 60):
public Score nextScore() {
System.out.println("making score");
return new Score(new Part(new Phrase(new Note(62, 0.25, 120))));
}
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Give it a try.
The other important bit is the "extends MPlayer". This mean that
the
class inherits some of the features of the MPlayer. In fact, the
nextScore() method is already defined in MPlayer, but we have
overwritten it for our own ends. It was designed like this - if
you don't include the nextScore() method, it will actually print
out "define the music to play by overwriting the nextScore method".
There are also other methods that you might want to use, such as:
getTempo(), setTempo(Tempo t) and setResolution(double d). Of
course because these are methods in MPlayer, you will acess them as
this.getTempo(), or simply getTempo() rather than defining an external
object.
Ideally you would want to create a graphical user interface to control
the formation of the score. For example, if you want a slider to
control the pitch, "just" create a GUI with a slider in it and use the
changeListener feature to control a variable that controls the
pitch. You can work out how to do GUIs from the java website,
using the forums and the documentation.
If makeing your own GUIs is a bit too much for you at the moment (GUI =
Graphical User Interface by the way), there is a jMusic tutorial called
helperGUI
that makes it fairly easy. Be careful if you plan to
use both HelperGUI and MPlayer at the same time - you can only extend
one class at a time in java. So what you would need to do is copy
the contents of MPlayer and make it extend HelperGUI. You could
call it MPlayerHelperGUI. Then when you extend this one, you are
getting the features of both.
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