「Unity でシンセを作るワークショップ」コピペ帳

unity-synth-workshop.js

////////////////////////////////
//////////////////////////////// BASIC SETUP
////////////////////////////////

var freq = 440.0;
var semitone = 0;
var octave = 0;

private var sampleRate = 44100.0;
private var time01 = 0.0;
private var noteOn = false;

function UpdateSynth() {
    freq = 440.0 * Mathf.Pow(2.0, (semitone - 9 + octave * 12) / 12.0);
}

function TickSynth() {
    // ---------------- EDIT HERE ----------------
    return Mathf.Sin(time01 * Mathf.PI * 2);
}

function Start() {
    sampleRate = AudioSettings.outputSampleRate;
}

function Update() {
    ProcessKeyboard();
    FindObjectOfType(OscilloscopeInput).freq = freq / 4;
}

function OnAudioFilterRead(data : float[], channels : int) {
    UpdateSynth();
    var delta = freq / sampleRate;
    for (var i = 0; i < data.Length; i += 2) {
        time01 += delta;
        time01 -= Mathf.Floor(time01);
        data[i] = data[i + 1] = TickSynth();
    }
}

private var keyboardArray = [
    'a', 'w', 's', 'e', 'd',
    'f', 't', 'g', 'y', 'h', 'u', 'j', 
    'k', 'o', 'l', 'p', ';'
];

private var lastPressedKey = '';

function ProcessKeyboard() {
    for (var i = 0; i < keyboardArray.Length; i++) {
        var key = keyboardArray[i];
        if (Input.GetKeyDown(key)) {
            semitone = i;
            lastPressedKey = key;
            noteOn = true;
        } else if (Input.GetKeyUp(key) && lastPressedKey == key) {
            lastPressedKey = '';
            noteOn = false;
        }
    }

    if (Input.GetKeyDown('z')) octave--;
    if (Input.GetKeyDown('x')) octave++;
}

////////////////////////////////
//////////////////////////////// WAVEFORM FUNCTIONS
////////////////////////////////

// Sine wave
return Mathf.Sin(time01 * Mathf.PI * 2);

// Sawtooth wave
return time01 * 2 - 1;

// Square wave
return time01 < 0.5 ? -1 : 1;

// Pulse wave
return time01 < modulation ? -1 : 1;

// Triange wave
return time01 < 0.25 ? time01 * 4 : (time01 < 0.75 ? 2.0 - time01 * 4.0 : time01 * 4 - 4);

// Saturated sine wave
return Mathf.Clamp(Mathf.Sin(time01 * Mathf.PI * 2) * 2.0, -1.0, 1.0);

// 4-bit Sine wave
return Mathf.Floor(Mathf.Sin(time01 * Mathf.PI * 2) * 8) / 8;

// FM Synthesis
var mod = Mathf.Sin(time01 * Mathf.PI * 2 * 8) * modulation;
return Mathf.Sin(time01 * Mathf.PI * 2 + mod);

////////////////////////////////
//////////////////////////////// ENVELOPE
////////////////////////////////

private var envelope = 0.0;
var attack = 0.1;
var release = 0.5;

function TickSynth() {
    if (noteOn) {
        envelope += 1.0 / (sampleRate * attack);
    } else {
        envelope -= 1.0 / (sampleRate * release);
    }
    envelope = Mathf.Clamp01(envelope);

    return Mathf.Sin(time01 * Mathf.PI * 2) * envelope;
}