Task Proxy

Sonic Pi uses the concept of live loops, i.e., named threaded loops that can be synchronized and updated on the fly. I found live loops extremely fun and useful, especially to explore new rythms and melodies. Is there something similar in SuperCollider? The answer is yes!

Tdef is part of the SuperCollider’s Just In Time programming library (JITLib) and allows us to register tasks by key. Registered tasks can be replaced with other task while playing. The old task and its replacement can automatically crossfade and the repalcement time can be quantized.

Evaluate the following code, change the message and re-evaluate the code. Observe the post window.

(
Tdef(\melody, {loop{
    "test".postln;
    0.25.wait;
}}).play;
)

This is great! Let us combine Tdef with Patterns play a melody that we can change on the fly:

(
Tdef(\melody, {
    var notes = Pseq([65, 70, 55, 63, 55, 70], inf).asStream;
    loop{
        Synth(\beep, [\freq: notes.next.midicps]);
        0.25.wait;
    }
}).play;
)

The same can be accomplished using a TaskProxy.

~melody = TaskProxy().play;
(
~melody.source = {
    var notes = Pseq([65, 70, 55, 63, 55, 70], inf).asStream;
    loop{
        Synth(\beep, [\freq: notes.next.midicps]);
        0.25.wait;
    }
};
)