[Sound] New pitch accessor

[beefchimi]

We should be able to adjust the pitch of each Sound. This probably should be restricted to Sound and unavailable on Stack or Earwurm.

Unlike playbackRate, there does not appear to be a simple solution to changing pitch. While there is a detune property on a AudioBufferSourceNode, apparently it is:

1. Not supported in Safari.
2. Appears to be the same as playbackRate but for cents instead of a "multiplier".

This will need to be investigated, as current solutions seem to indicate a new for a AudioWorklet:

• AudioFrequencyWorkerNode for working in the Frequency Domain WebAudio/web-audio-api#468
• Interdependence between playbackRate and detune WebAudio/web-audio-api#723
• Real-time pitch adjustment WebAudio/web-audio-api#2443
• Ability to change the playback rate of an AudioBufferSourceNode without affecting the pitch WebAudio/web-audio-api#2487
• https://github.com/olvb/phaze/tree/master

Implementation

this._pitch = 1;

get pitch() {
    return this._pitch;
}

set pitch(value: number) {
    const oldPitch = this._pitch;
    const newPitch = clamp(tokens.minPitch, value, tokens.maxPitch);

    if (oldPitch === newPitch) return;

    this._pitch = newPatch;
    this.emit('pitch', newPitch);

    // Do something to actually change sound pitch...
}

Usage

const sound1 = await stack.prepare();
// Should be `1` by default.
const currentPitch = sound1.pitch;

// If using a Setter:
sound1.pitch = 2;

// Otherwise, if we prefer a method:
sound1.setPitch(2, 1000);

const sound2 = await stack.prepare({pitch: 2});
const sound3 = new Sound(...props, {pitch: 2});

Key points

• Defaults to 1.
• Can “ramp to” changed values.
  • Reference: [Earwurm] Accessor vs method pattern #29
• Consider applying a custom default in the constructor?