loopy_synth.js

var asynth = require('../');
var jynth = require('jynth');

var synth = jynth();

var recording = true;
var playing = true;
var samples = [];

process.stdin.setRawMode(true);
process.stdin.on('data', function (buf) {
    if (buf[0] === 3) process.exit();
    if (buf[0] === ' '.charCodeAt(0)) {
        recording = !recording;
        console.log('recording ' + recording);
        if (recording) samples = [];
    }
    if (buf[0] === 'p'.charCodeAt(0)) {
        playing = !playing;
        console.log('playing ' + playing);
    }
});
process.stdin.resume();

var notes = {};

var s = asynth(function (note, t) {
    var freq = 440 * Math.pow(2, (note.key - 49) / 12);
    
    if (!notes[note.key]) {
        notes[note.key] = true;
        setTimeout(function () {
            notes[note.key] = false;
        }, 8000);
        samples.splice(0);
    }
    
    var x = synth(t)
        .sine(0.1, freq)
        .amod(freq/200,freq/100,3)
        .sample
    ;
    var y = synth(t)
        .sine(1, freq)
        .sample
    ;
    
    var value = x + y;
    
    if (recording) samples.push(value);
    if (samples.length > 44000 * 16) samples.splice(0, 44000);
    return value;
});

s.push(function (t, i) {
    if (!playing) return 0;
    return samples[i % samples.length];
});

s.play();