apple2js/js/ui/audio.ts
2021-04-25 12:09:30 -07:00

131 lines
3.6 KiB
TypeScript

/* Copyright 2010-2019 Will Scullin <scullin@scullinsteel.com>
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation. No representations are made about the suitability of this
* software for any purpose. It is provided "as is" without express or
* implied warranty.
*/
import { BOOLEAN_OPTION, OptionHandler } from './options_modal';
import Apple2IO from '../apple2io';
import { debug } from '../util';
/*
* Audio Handling
*/
const SAMPLE_SIZE = 1024;
const SAMPLE_RATE = 44000;
export const SOUND_ENABLED_OPTION = 'enable_sound';
declare global {
interface Window {
webkitAudioContext: AudioContext;
}
}
const AudioContext = window.AudioContext || window.webkitAudioContext;
export class Audio implements OptionHandler {
private sound = true;
private samples: number[][] = [];
private audioContext;
private audioNode;
private started = false;
constructor(io: Apple2IO) {
this.audioContext = new AudioContext({
sampleRate: SAMPLE_RATE
});
// TODO(flan): MDN says that createScriptProcessor is deprecated and
// replaced by AudioWorklet. FF and Chrome support AudioWorklet, but
// Safari does not (yet).
this.audioNode = this.audioContext.createScriptProcessor(SAMPLE_SIZE, 1, 1);
this.audioNode.onaudioprocess = (event) => {
const data = event.outputBuffer.getChannelData(0);
const sample = this.samples.shift();
let idx = 0;
let len = data.length;
if (sample) {
len = Math.min(sample.length, len);
for (; idx < len; idx++) {
data[idx] = sample[idx];
}
}
for (; idx < data.length; idx++) {
data[idx] = 0.0;
}
};
this.audioNode.connect(this.audioContext.destination);
io.sampleRate(this.audioContext.sampleRate, SAMPLE_SIZE);
io.addSampleListener((sample: number[]) => {
if (this.sound) {
if (this.samples.length < 5) {
this.samples.push(sample);
}
}
});
window.addEventListener('keydown', this.autoStart);
if (window.ontouchstart !== undefined) {
window.addEventListener('touchstart', this.autoStart);
}
window.addEventListener('mousedown', this.autoStart);
debug('Sound initialized');
}
autoStart = () => {
if (this.audioContext && !this.started) {
this.samples = [];
this.audioContext.resume();
this.started = true;
}
}
start = () => {
if (this.audioContext) {
this.samples = [];
this.audioContext.resume();
}
}
isEnabled = () => {
return this.sound;
}
getOptions() {
return [
{
name: 'Audio',
options: [
{
name: SOUND_ENABLED_OPTION,
label: 'Enabled',
type: BOOLEAN_OPTION,
defaultVal: true,
}
]
}
];
}
setOption = (name: string, value: boolean) => {
switch (name) {
case SOUND_ENABLED_OPTION:
this.sound = value;
}
}
}