supercollider synth to midi / control bus demo

sc_synth_to_midi.scd

MIDIClient.init; // initialize MIDI
m = MIDIOut(0);  // get the first output device

Routine { // use a Routine (aka a thread) for synchronization with the server
	s = Server.default;
	s.boot;
	s.sync; // wait for the server to be ready

	// a control-rate bus which our synth will write to
	~lfo_out_bus = Bus.control(s, 1);

	// make a new synthdef (a control-rate sine)...
	~lfo = SynthDef.new(\lfo, {
		arg hz=1, out, mul=1, add=0;
		Out.kr(out, SinOsc.kr(hz, mul:mul, add:add));
	}).play(target:s, ///... and play it on the server...
		args: [   //... with some arguments...
			\out, ~lfo_out_bus.index // ... including the target bus
		]
	);


	// now there are different things we could do to read the bus.
	// here, we'll just explicitly read values from it in an endless loop.
	inf.do {
		~lfo_out_bus.get(
			// getting a bus value is asnychronous, so the method takes a callback...
			{
				arg val; // ...whose argument is the bus value.
				var scaled; // the value is in [-1, 1], so we want to rescale it
				scaled = (val+1)/2 * 127;
				postln(scaled);
				m.control(1, 10, scaled); // send it out on CC 10, channel 1 (or 2 if your client is 1-based!)
			}
		);
		0.1.wait; // initiate a read every 100 milliseconds
		// (we could go faster but this is so we don't choke on the print statements)
	}

}.play; // make everything go




/// if we want to, say, modulate the LFO speed with another lfo,
/// another control bus is the way to do it

// this is a bit hacky, but we'll just make another routine here...
Routine {
	8.wait; // ... and use it to wait for some arbitrary time for the earlier stuff to happen
	~lfo_hz_bus = Bus.control(s, 1); // make another bus
	~lfo.map(\hz, ~lfo_hz_bus); // map it to the synth
	~lfo_mod = Synth.new(\lfo, // we already sent this def to the server
		args: [
			\hz, 0.2,        // slower
			\add:1.1,          // scaled up to [0.1, 2.1]
			\out, ~lfo_hz_bus.index // and sending to the modulation bus
		],
		target: ~lfo, addAction:\addBefore // make sure the modulator executes before its destination
	);
}.play; // make it go

I am also using this solution but the outgoing MIDI control values have discontinuities and produce clicks. So there needs to be an interpolation - but how would that work (since it is not on the server)?