(function() {
var onDOMContentLoaded = function() {
window.AudioContext = window.AudioContext || window.webkitAudioContext;
try {
// Create the instance of AudioContext
var context = new AudioContext();
} catch (error) {
window.alert(error.message + ' : Please use Chrome or Safari.');
return;
}
var displayProperties = function(node, tableid, caption) {
var html = '<caption>' + caption + '</caption>';
html += '<thead>';
html += '<tr>';
html += '<th scope="col">Property</th>';
html += '<th scope="col">Value</th>';
html += '<th scope="col">hasOwnProperty</th>';
html += '</tr>';
html += '</thead>';
html += '<tbody>';
for (var key in node) {
html += '<tr>';
html += '<td>' + key + '</td>';
html += '<td>' + node[key] + '</td>';
html += '<td>' + node.hasOwnProperty(key) + '</td>';
html += '</tr>';
}
html += '</tbody>';
document.getElementById(tableid).innerHTML = html;
document.getElementById(tableid).parentNode.previousElementSibling.style.display = 'block';
};
// Create the instance of OscillatorNode
var oscillator = context.createOscillator();
// Parameter for the instance of OscillatorNode
var type = oscillator.type;
// for legacy browsers
context.createGain = context.createGain || context.createGainNode;
// Create the instance of GainNode (for Master Volume)
var gain = context.createGain();
// Delay
// for legacy browsers
context.createDelay = context.createDelay || context.createDelayNode;
var MAX_DELAY_TIME = 1;
// Create the instance of DelayNode
var delay = context.createDelay(MAX_DELAY_TIME);
// Create the instance of GainNode (for Delay)
var dry = context.createGain();
var wet = context.createGain();
var feedback = context.createGain();
// Initialize parameters for Delay
delay.delayTime.value = document.getElementById('range-delay-time').valueAsNumber;
dry.gain.value = document.getElementById('range-delay-dry').valueAsNumber;
wet.gain.value = document.getElementById('range-delay-wet').valueAsNumber;
feedback.gain.value = document.getElementById('range-delay-feedback').valueAsNumber;
// Flag for starting or stopping sound
var isStop = true;
/*
* Event Listener
*/
// Start or Stop sound
var PIANO_88S = [
'A-4', 'A-4h', 'B-4',
'C-3', 'C-3h', 'D-3', 'D-3h', 'E-3', 'F-3', 'F-3h', 'G-3', 'G-3h', 'A-3', 'A-3h', 'B-3',
'C-2', 'C-2h', 'D-2', 'D-2h', 'E-2', 'F-2', 'F-2h', 'G-2', 'G-2h', 'A-2', 'A-2h', 'B-2',
'C-1', 'C-1h', 'D-1', 'D-1h', 'E-1', 'F-1', 'F-1h', 'G-1', 'G-1h', 'A-1', 'A-1h', 'B-1',
'C', 'Ch', 'D', 'Dh', 'E', 'F', 'Fh', 'G', 'Gh', 'A', 'Ah', 'B',
'C1', 'C1h', 'D1', 'D1h', 'E1', 'F1', 'F1h', 'G1', 'G1h', 'A1', 'A1h', 'B1',
'C2', 'C2h', 'D2', 'D2h', 'E2', 'F2', 'F2h', 'G2', 'G2h', 'A2', 'A2h', 'B2',
'C3', 'C3h', 'D3', 'D3h', 'E3', 'F3', 'F3h', 'G3', 'G3h', 'A3', 'A3h', 'B3',
'C4'
];
var pianoKeys = Array.prototype.slice.call(document.querySelectorAll('#piano ul li'), 0);
var convertIndex = function(index) {
//
// The 12 equal temparement
//
// Min -> A 27.5Hz, Max -> C 4186 Hz
//
// Example :
// A * 1.059463 -> A# (half up)
//
var FREQUENCY_RATIO = Math.pow(2, (1 / 12)); // about 1.059463;
var MIN_A = 27.5;
return (MIN_A * Math.pow(FREQUENCY_RATIO, index));
};
pianoKeys.forEach(function(element, index, array) {
// Start sound
element.addEventListener(EventWrapper.START, function(event) {
if (!isStop) {
oscillator.stop(0);
}
var pianoIndex = PIANO_88S.indexOf(this.id);
var frequency = convertIndex(pianoIndex);
// Create the instance of OscillatorNode
oscillator = context.createOscillator();
// for legacy browsers
oscillator.start = oscillator.start || oscillator.noteOn;
oscillator.stop = oscillator.stop || oscillator.noteOff;
// GainNode (Master Volume) -> AudioDestinationNode (Output)
gain.connect(context.destination);
// Connect nodes for original sound
// OscillatorNode (Input) -> GainNode (Dry) -> GainNode (Master Volume) (-> AudioDestinationNode (Output))
oscillator.connect(dry);
dry.connect(gain);
// Connect nodes for effect (Delay) sound
// OscillatorNode (Input) -> DelayNode (Delay) -> GainNode (Wet) -> GainNode (Master Volume) (-> AudioDestinationNode (Output))
oscillator.connect(delay);
delay.connect(wet);
wet.connect(gain);
// Connect nodes for Feedback
// (OscillatorNode (Input) ->) DelayNode (Delay) -> GainNode (Feedback) -> DelayNode (Delay) -> ...
delay.connect(feedback);
feedback.connect(delay);
// Set parameters
oscillator.type = type;
oscillator.frequency.value = frequency;
oscillator.start(0);
isStop = false;
this.classList.remove('key-off');
this.classList.add('key-on');
}, false);
// Stop sound
element.addEventListener(EventWrapper.END, function() {
if (isStop) {
return;
}
oscillator.stop(0);
isStop = true;
this.classList.remove('key-on');
this.classList.add('key-off');
}, false);
});
// Control Master Volume
document.getElementById('range-volume').addEventListener('input', function() {
var min = gain.gain.minValue || 0;
var max = gain.gain.maxValue || 1;
if ((this.valueAsNumber >= min) && (this.valueAsNumber <= max)) {
gain.gain.value = this.valueAsNumber;
document.getElementById('output-volume').textContent = this.value;
}
}, false);
// Select type
document.getElementById('form-wave-type').addEventListener('change', function() {
for (var i = 0, len = this.elements['radio-wave-type'].length; i < len; i++) {
if (this.elements['radio-wave-type'][i].checked) {
oscillator.type = type = (typeof oscillator.type === 'string') ? this.elements['radio-wave-type'][i].value : i;
break;
}
}
}, false);
// Control delayTime
document.getElementById('range-delay-time').addEventListener('input', function() {
var min = delay.delayTime.minValue || 0;
var max = delay.delayTime.maxValue || 1;
if ((this.valueAsNumber >= min) && (this.valueAsNumber <= max)) {
delay.delayTime.value = this.valueAsNumber;
document.getElementById('output-delay-time').textContent = this.value;
displayProperties(delay.delayTime, 'delaynode-delaytime-properties', 'delayTime (AudioParam) ');
}
}, false);
// Control Delay Dry
document.getElementById('range-delay-dry').addEventListener('input', function() {
var min = dry.gain.minValue || 0;
var max = dry.gain.maxValue || 1;
if ((this.valueAsNumber >= min) && (this.valueAsNumber <= max)) {
dry.gain.value = this.valueAsNumber;
document.getElementById('output-delay-dry').textContent = this.value;
}
}, false);
// Control Delay Wet
document.getElementById('range-delay-wet').addEventListener('input', function() {
var min = wet.gain.minValue || 0;
var max = wet.gain.maxValue || 1;
if ((this.valueAsNumber >= min) && (this.valueAsNumber <= max)) {
wet.gain.value = this.valueAsNumber;
document.getElementById('output-delay-wet').textContent = this.value;
}
}, false);
// Control Delay Feedback
document.getElementById('range-delay-feedback').addEventListener('input', function() {
var min = feedback.gain.minValue || 0;
var max = feedback.gain.maxValue || 1;
if ((this.valueAsNumber >= min) && (this.valueAsNumber <= max)) {
feedback.gain.value = this.valueAsNumber;
document.getElementById('output-delay-feedback').textContent = this.value;
}
}, false);
/*
* Display properties
*/
displayProperties(delay, 'delaynode-properties', 'DelayNode');
displayProperties(delay.delayTime, 'delaynode-delaytime-properties', 'delayTime (AudioParam) ');
};
if ((document.readyState === 'interactive') || (document.readyState === 'complete')) {
onDOMContentLoaded();
} else {
document.addEventListener('DOMContentLoaded', onDOMContentLoaded, true);
}
})();
function EventWrapper(){
}
(function(){
var click = '';
var start = '';
var move = '';
var end = '';
// Touch Panel ?
if (/iPhone|iPad|iPod|Android/.test(navigator.userAgent)) {
click = 'click';
start = 'touchstart';
move = 'touchmove';
end = 'touchend';
} else {
click = 'click';
start = 'mousedown';
move = 'mousemove';
end = 'mouseup';
}
EventWrapper.CLICK = click;
EventWrapper.START = start;
EventWrapper.MOVE = move;
EventWrapper.END = end;
})();