compact_sets/supercollider/osc_receiver.scd

// osc_receiver.scd - OSC receiver for webapp
// Run this in SuperCollider: sclang supercollider/osc_receiver.scd
// Then click nodes in the webapp to play tones

s.boot;
s.waitForBoot {

    // Define synth on the server with long attack and decay
    SynthDef(\sineTone, {
        |freq = 440, amp = 0.15|
        var env = EnvGen.kr(
            Env([0, 1, 0.8, 0], [2, 3.0, 3], \sin),
            doneAction: Done.freeSelf
        );
        Out.ar(0, SinOsc.ar(freq) * env * amp);
    }).add;

    // Wait for synth to be added to server
    s.sync;

    // OSC handler for /freq messages - explicitly bind to port 57120
    ~oscHandler = OSCFunc({ |msg, time, addr, recvPort|
        if (msg.size >= 3, {
            var freq = msg[2].asFloat;
            if (freq > 0, {
                Synth(\sineTone, [\freq, freq, \amp, 0.15]);
            });
        });
    }, '/freq', nil, 57120);

    "OSC receiver ready on port 57120".postln;
    "Click nodes in webapp to play".postln;

    // Keep alive
    while { true } { 10.wait; };
}