mirror of
https://github.com/whscullin/apple2js.git
synced 2024-01-12 14:14:38 +00:00
143 lines
3.9 KiB
JavaScript
143 lines
3.9 KiB
JavaScript
/* -*- mode: JavaScript; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/* Copyright 2010-2014 Will Scullin <scullin@scullinsteel.com>
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*
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* Permission to use, copy, modify, distribute, and sell this software and its
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* documentation for any purpose is hereby granted without fee, provided that
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* the above copyright notice appear in all copies and that both that
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* copyright notice and this permission notice appear in supporting
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* documentation. No representations are made about the suitability of this
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* software for any purpose. It is provided "as is" without express or
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* implied warranty.
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*/
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/*jshint jquery: true, browser: true */
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/*globals io: false, toHex:false, debug: false */
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/*exported playSample, enableSound, initAudio */
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/*
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* Audio Handling
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*/
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var sound = true;
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// 8000 = 0x1f40 = 64, 31
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// 16000 = 0x3e80 = 128, 62
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var wavHeader =
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['R','I','F','F',68 ,3 ,0 ,0 ,'W','A','V','E','f','m','t',' ',
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16 ,0 ,0 ,0 ,1 ,0 ,1 ,0 ,128,62 ,0 ,0 ,128,62 ,0 ,0 ,
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1 ,0 ,8 ,0 ,'d','a','t','a',32 ,3 ,0 ,0 ];
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function percentEncode(ary) {
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var buf = "";
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for (var idx = 0; idx < ary.length; idx++) {
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buf += "%" + toHex(ary[idx]);
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}
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return buf;
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}
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wavHeader = $.map(wavHeader, function(n) {
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return typeof(n) == "string" ? n.charCodeAt(0) : n;
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});
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var wavHeaderStr = percentEncode(wavHeader);
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var audioAPI = false;
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var audioMoz = false;
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var audioContext;
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var audioNode;
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var audio, audio2;
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function initAudio() {
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var AC = window.webkitAudioContext || window.AudioContext;
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if (typeof AC != "undefined") {
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debug("Using Web Audio API");
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audioAPI = true;
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audioContext = new AC();
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audioNode = audioContext.createScriptProcessor(4096, 1, 1);
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io.floatAudio(audioContext.sampleRate);
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audioNode.onaudioprocess = function(event) {
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var data = event.outputBuffer.getChannelData(0);
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var sample = io.getSample();
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var delta = 1; // sample.length / data.length;
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var idx, kdx;
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for (idx = 0, kdx = 0;
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idx < data.length && parseInt(kdx, 10) < sample.length;
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kdx += delta, idx++) {
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data[idx] = sample[parseInt(kdx, 10)];
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}
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for (; idx < data.length; idx++) {
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data[idx] = sample[sample.length - 1];
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}
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};
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} else {
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audio = document.createElement("audio");
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if (audio.mozSetup) {
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debug("Using Mozilla Audio API");
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audio.mozSetup(1, 16000);
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io.floatAudio(16000);
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audioMoz = true;
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} else {
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debug("Using audio elements");
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audio2 = document.createElement("audio");
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}
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}
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}
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function playSample() {
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// [audio,audio2] = [audio2,audio];
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var sample = io.getSample();
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if (!sound) {
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return;
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}
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if (audioMoz) {
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audio.mozWriteAudio(sample);
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return;
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}
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var tmp = audio;
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audio = audio2;
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audio2 = tmp;
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if (sample && sample.length) {
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var len = sample.length,
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buf = sample.join(""),
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o1 = percentEncode([(len + 36) & 0xff, (len + 36) >> 8]),
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o2 = percentEncode([len & 0xff, len >> 8]),
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header = wavHeaderStr.replace("%44%03",o1).replace("%20%03", o2);
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audio.src = "data:audio/x-wav," + header + buf;
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// debug(audio.src);
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audio.play();
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}
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}
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function enableSound(on)
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{
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sound = on;
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if (audioAPI) {
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if (sound) {
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audioNode.connect(audioContext.destination);
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} else {
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audioNode.disconnect();
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}
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} else {
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if (sound) {
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if (audio) audio.volume = 0.5;
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if (audio2) audio2.volume = 0.5;
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} else {
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io.getSample(true);
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}
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}
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}
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