a-440.github.io/oscillator.html at master · a-440/a-440.github.io · GitHub

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<html>
<head>
<meta charset="utf-8">
<meta name="Description" CONTENT="A simple page and site that plays a tone at 440 hz, also known as A 440">

<title>A-440</title>

<link rel="shortcut icon" href="/favicon.ico" type="image/x-icon">
<link rel="icon" href="/favicon.ico" type="image/x-icon">

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>

<script type="text/javascript">

/*
  Thanks to Boris @ http://www.html5rocks.com/en/tutorials/webaudio/intro/ !
*/

$(document).ready(function(){


	var iOS = ( navigator.userAgent.match(/(iPad|iPhone|iPod)/g) ? true : false );


	var context = null;
	var oscillator = null;
	var gain = null;
	var analyser = null;
	var playing = false;

	window.AudioContext = window.AudioContext || window.webkitAudioContext;
	context = new AudioContext();


  $('#container,.center').click(function(e) {
    var offset = $(this).offset();

    //console.log(e.clientX - offset.left);
    //console.log(e.clientY - offset.top);

    var frequency = e.clientX - offset.left;
    var amp = e.clientY - offset.top;

    if (playing) {
      //dbl-click to stop
      return;
    }

    gainNode = context.createGain();
    gainNode.gain.value = 0.5; //initial value
    gainNode.connect( context.destination );

    analyser = context.createAnalyser();
    analyser.fftSize = 1024;
    analyser.smoothingTimeConstant = 0.9;
    analyser.connect( context.destination );

    oscillator = context.createOscillator();
    oscillator.connect( analyser ); //was gainNode

	oscillator.frequency.value = frequency/2;
	oscillator.detune.value =  0;
	oscillator.type = oscillator.SINE;
	oscillator.start(0);
	playing = true;


	$('#a').hide();
	$('#b,#c').show();


	requestAnimFrame( visualize.bind() ) ;


  });


$('#container,.center').mousemove( function(e){

	_gain = ( e.clientY );
	//console.log( (Math.abs(_gain) * -1 )   );
	if(oscillator){
	  oscillator.frequency.value = e.pageX;

	}
});

$('#container,.center').dblclick( function(e){
	oscillator ? oscillator.stop(0) : null;
    playing = false;
    $('#b,#c').hide();
    $('#a').show();

});


$('#b,#c').hide();


visualize = function() {
  var canvas = $('#monitor');
  canvas = document.querySelector('canvas');

  //console.log(canvas.context);

  var HEIGHT = '120';
  var WIDTH  = '600';
  canvas.width = WIDTH;
  canvas.height = HEIGHT;
  var drawContext = canvas.getContext('2d');

  var times = new Uint8Array( analyser.frequencyBinCount );

  analyser.getByteTimeDomainData(times);

  for (var i = 0; i < times.length; i++) {
    var value = times[i];
    var percent = value / 256;
    var height = HEIGHT * percent;
    var offset = HEIGHT - height - 1;
    var barWidth = WIDTH/times.length;
    drawContext.fillStyle = 'blue';
    drawContext.fillRect(i * barWidth, offset, 2, 2);
  }
  requestAnimFrame( visualize.bind() ) ;
};


window.requestAnimFrame = (function(){
	return  window.requestAnimationFrame       ||
  			window.webkitRequestAnimationFrame ||
  			window.mozRequestAnimationFrame    ||
  			window.oRequestAnimationFrame      ||
  			window.msRequestAnimationFrame     ||
  	function( callback ){
  		window.setTimeout(callback, 1000 / 60);
	};
})();


}); //end document.ready(...)


</script>

<style type="text/css">
@import url(http://fonts.googleapis.com/css?family=Over+the+Rainbow);

  body  {
    background-color: #fff;
    font-family: 'Over the Rainbow';
    font-size: 2em;
    text-align: center;
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
    cursor: default;
  }


  .canvas {
    width: 100%;
    height: auto;
    bottom: 0px;
    top: 0px;
    left: 0;
    position: absolute;
  }

  .center {
    font-family: 'Over the Rainbow';
    font-size: 2em;
    position: fixed;
    border: 0px ridge gray;
    top: 50%;
    left: 55%;
    margin-top: -200px;
    margin-left: -400px;
    cursor: inherit;

  }

  #monitor {
    position: fixed;
    border: 0px dotted gray;
    top: 90%;
    left: 56%;
    margin-top: -200px;
    margin-left: -400px;
    cursor: inherit;
    z-index: -1;

  }

</style>

</head>

<body>


<div class="canvas" id="container" style="width:100%;height:100%">
  <svg width="100%" height="100%" xmlns="http://www.w3.org/2000/svg">
    <defs>
      <pattern id="smallGrid" width="8" height="8" patternUnits="userSpaceOnUse">
        <path d="M 8 0 L 0 0 0 8" fill="none" stroke="#eaeaea" stroke-width="0.5"/>
      </pattern>
      <pattern id="grid" width="80" height="80" patternUnits="userSpaceOnUse">
        <rect width="80" height="80" fill="url(#smallGrid)"/>
        <path d="M 80 0 L 0 0 0 80" fill="none" stroke="#eaeaea" stroke-width="1"/>
      </pattern>
    </defs>

    <rect width="100%" height="100%" fill="url(#grid)" />
  </svg>

</div>


<div class="center">
	<span id="a"> Click anywhere to start </span>
	<span id="b"> Move your mouse </span><br />
	<span id="c"> Double-click to shut up </span>
</div>

<canvas id="monitor" />

</body>
</html>