moust · June 24, 2015 14:52
diff --git a/oscilloscope.html b/oscilloscope.html
 <!doctype html>
 <html>
    <head>
        <meta charset="utf-8" />
        <title>Oscilloscope</title>
        <style type="text/css">
            .visualizer {
                display: block;
                width: 100%;
                height: auto;
            }
            audio {
                display: block;
                width: 100%;
                margin: 10px;
            }
        </style>
    </head>
    <body>

        <canvas class="visualizer" width="1280" height="720"></canvas>

        <script type="text/javascript" src="bower_components/dat-gui/build/dat.gui.min.js"></script>
        <script type="text/javascript" src="bower_components/stats.js/build/stats.min.js"></script>
        <script>
        (function () {

            var stats = new Stats();
            stats.setMode(0); // 0: fps, 1: ms
            // align top-left
            stats.domElement.style.position = 'absolute';
            stats.domElement.style.left = '0px';
            stats.domElement.style.top = '0px';
            document.body.appendChild( stats.domElement );

            var canvas = document.querySelector('.visualizer');
            var canvasCtx = canvas.getContext("2d");
            canvasCtx.lineWidth = 2;

            var audioCtx = new (window.AudioContext || window.webkitAudioContext)();

            var analyser = audioCtx.createAnalyser();
            // analyser.minDecibels = -90;
            // analyser.maxDecibels = -10;
            analyser.smoothingTimeConstant = 0.85;
            analyser.fftSize = Math.pow(2, Math.round(Math.log2(canvas.width)));

            var gainNode = audioCtx.createGain();

            var audio = new Audio();
            audio.src = 'paradise_circus.mp3';
            audio.controls = true;
            audio.autoplay = true;
            document.body.appendChild(audio);

            audio.addEventListener('canplay', function(e) {
                gotStream(audio);
            }, false);

            // navigator.getUserMedia = ( navigator.getUserMedia ||
            //                         navigator.webkitGetUserMedia ||
            //                         navigator.mozGetUserMedia ||
            //                         navigator.msGetUserMedia);

            // navigator.getUserMedia({audio: true}, gotStream, console.error);

            function gotStream (stream) {
                // source = audioCtx.createMediaStreamSource(stream);
                source = audioCtx.createMediaElementSource(audio);
                source.connect(analyser);
                analyser.connect(gainNode);
                gainNode.connect(audioCtx.destination);

                canvasCtx.clearRect(0, 0, canvas.width, canvas.height);

                draw();
            }

            function draw () {
                drawVisual = requestAnimationFrame(draw);

                canvasCtx.fillStyle = 'rgb(200, 200, 200)';
                canvasCtx.fillRect(0, 0, canvas.width, canvas.height);

                drawByteFrequencyData();

                drawByteTimeDomainData();

                stats.update();
            }

            function drawByteTimeDomainData () {
                var bufferLength = analyser.frequencyBinCount;
                var dataArray = new Uint8Array(bufferLength);
                analyser.getByteTimeDomainData(dataArray);

                canvasCtx.lineWidth = 2;
                canvasCtx.strokeStyle = 'rgb(0, 0, 0)';
                canvasCtx.lineJoin = canvasCtx.lineCap = 'round';

                canvasCtx.beginPath();

                var sliceWidth = canvas.width * 1.0 / bufferLength;
                var x = 0;
                for(var i = 0; i < bufferLength; i++) {
                    var value = dataArray[i] / 128.0;
                    var y = value * canvas.height / 2;
                    if(i === 0) {
                        canvasCtx.moveTo(x, y);
                    } else {
                        canvasCtx.lineTo(x, y);
                    }
                    x += sliceWidth;
                }

                canvasCtx.lineTo(canvas.width, canvas.height / 2);
                canvasCtx.stroke();
            }

            function drawByteFrequencyData () {
                var bufferLength = analyser.frequencyBinCount;
                var dataArray = new Uint8Array(bufferLength);
                analyser.getByteFrequencyData(dataArray);

                for ( var i = 0; i < (bufferLength); i++ ) {
                    var value = dataArray[i];
                    var percent = value / 256;
                    var height = canvas.height * percent;
                    var offset = canvas.height - height - 1;
                    var barWidth = canvas.width / analyser.frequencyBinCount;
                    var hue = i / analyser.frequencyBinCount * 360;
                    canvasCtx.fillStyle = 'hsla(' + hue + ', 100%, 50%, 0.5)';
                    canvasCtx.fillRect(i * barWidth, offset, barWidth, height);
                }
            }

            function indexToFreq(analyser, index) {
                var nyquist = audioCtx.sampleRate / 2;
                return nyquist/(analyser.fftSize/2) * index;
            }

            var gui = new dat.GUI();

            var f1 = gui.addFolder('Analyser');
            f1.open();
            f1.add(analyser, 'minDecibels', -100, 0);
            f1.add(analyser, 'maxDecibels', -100, 0);
            f1.add(analyser, 'smoothingTimeConstant', 0, 1).step(0.01);
            f1.add(analyser, 'fftSize', [32,64,128,256,512,1024,2048]);

            var f2 = gui.addFolder('Visualizer');
            f2.open();
            f2.add(canvasCtx, 'lineWidth');

        })();
        </script>
    </body>
 </html>
	<!doctype html>
	<html>
	<head>
	<meta charset="utf-8" />
	<title>Oscilloscope</title>
	<style type="text/css">
	.visualizer {
	display: block;
	width: 100%;
	height: auto;
	}
	audio {
	display: block;
	width: 100%;
	margin: 10px;
	}
	</style>
	</head>
	<body>

	<canvas class="visualizer" width="1280" height="720"></canvas>

	<script type="text/javascript" src="bower_components/dat-gui/build/dat.gui.min.js"></script>
	<script type="text/javascript" src="bower_components/stats.js/build/stats.min.js"></script>
	<script>
	(function () {

	var stats = new Stats();
	stats.setMode(0); // 0: fps, 1: ms
	// align top-left
	stats.domElement.style.position = 'absolute';
	stats.domElement.style.left = '0px';
	stats.domElement.style.top = '0px';
	document.body.appendChild( stats.domElement );

	var canvas = document.querySelector('.visualizer');
	var canvasCtx = canvas.getContext("2d");
	canvasCtx.lineWidth = 2;

	var audioCtx = new (window.AudioContext \|\| window.webkitAudioContext)();

	var analyser = audioCtx.createAnalyser();
	// analyser.minDecibels = -90;
	// analyser.maxDecibels = -10;
	analyser.smoothingTimeConstant = 0.85;
	analyser.fftSize = Math.pow(2, Math.round(Math.log2(canvas.width)));

	var gainNode = audioCtx.createGain();

	var audio = new Audio();
	audio.src = 'paradise_circus.mp3';
	audio.controls = true;
	audio.autoplay = true;
	document.body.appendChild(audio);

	audio.addEventListener('canplay', function(e) {
	gotStream(audio);
	}, false);

	// navigator.getUserMedia = ( navigator.getUserMedia \|\|
	// navigator.webkitGetUserMedia \|\|
	// navigator.mozGetUserMedia \|\|
	// navigator.msGetUserMedia);

	// navigator.getUserMedia({audio: true}, gotStream, console.error);

	function gotStream (stream) {
	// source = audioCtx.createMediaStreamSource(stream);
	source = audioCtx.createMediaElementSource(audio);
	source.connect(analyser);
	analyser.connect(gainNode);
	gainNode.connect(audioCtx.destination);

	canvasCtx.clearRect(0, 0, canvas.width, canvas.height);

	draw();
	}

	function draw () {
	drawVisual = requestAnimationFrame(draw);

	canvasCtx.fillStyle = 'rgb(200, 200, 200)';
	canvasCtx.fillRect(0, 0, canvas.width, canvas.height);

	drawByteFrequencyData();

	drawByteTimeDomainData();

	stats.update();
	}

	function drawByteTimeDomainData () {
	var bufferLength = analyser.frequencyBinCount;
	var dataArray = new Uint8Array(bufferLength);
	analyser.getByteTimeDomainData(dataArray);

	canvasCtx.lineWidth = 2;
	canvasCtx.strokeStyle = 'rgb(0, 0, 0)';
	canvasCtx.lineJoin = canvasCtx.lineCap = 'round';

	canvasCtx.beginPath();

	var sliceWidth = canvas.width * 1.0 / bufferLength;
	var x = 0;
	for(var i = 0; i < bufferLength; i++) {
	var value = dataArray[i] / 128.0;
	var y = value * canvas.height / 2;
	if(i === 0) {
	canvasCtx.moveTo(x, y);
	} else {
	canvasCtx.lineTo(x, y);
	}
	x += sliceWidth;
	}

	canvasCtx.lineTo(canvas.width, canvas.height / 2);
	canvasCtx.stroke();
	}

	function drawByteFrequencyData () {
	var bufferLength = analyser.frequencyBinCount;
	var dataArray = new Uint8Array(bufferLength);
	analyser.getByteFrequencyData(dataArray);

	for ( var i = 0; i < (bufferLength); i++ ) {
	var value = dataArray[i];
	var percent = value / 256;
	var height = canvas.height * percent;
	var offset = canvas.height - height - 1;
	var barWidth = canvas.width / analyser.frequencyBinCount;
	var hue = i / analyser.frequencyBinCount * 360;
	canvasCtx.fillStyle = 'hsla(' + hue + ', 100%, 50%, 0.5)';
	canvasCtx.fillRect(i * barWidth, offset, barWidth, height);
	}
	}

	function indexToFreq(analyser, index) {
	var nyquist = audioCtx.sampleRate / 2;
	return nyquist/(analyser.fftSize/2) * index;
	}

	var gui = new dat.GUI();

	var f1 = gui.addFolder('Analyser');
	f1.open();
	f1.add(analyser, 'minDecibels', -100, 0);
	f1.add(analyser, 'maxDecibels', -100, 0);
	f1.add(analyser, 'smoothingTimeConstant', 0, 1).step(0.01);
	f1.add(analyser, 'fftSize', [32,64,128,256,512,1024,2048]);

	var f2 = gui.addFolder('Visualizer');
	f2.open();
	f2.add(canvasCtx, 'lineWidth');

	})();
	</script>
	</body>
	</html>