JavaScript

语言：

JaveScriptBabelCoffeeScript

确定

var minY = 135; //lowest point

var maxY = 10; //highest point

var pausePosition = 0.75; //position of balls when not playing, percentage

var reverse = false; //reverse lowest and highest

var offsetBalls = true; //mix balls

var smoothFac = 0.85; //value smoothing for ball position

var smoothFacPause = 0.975; //value smoothing when paused

var cutoffLow = 0.1; //percentage of sound spectrum that's cut off from the bottom

var cutoffHigh = 0.65; //percentage of sound spectrum that's cut off from the top

var songUrl = "http://reneroth.org/projects/codepen/dornendiamant.ogg"; //this needs correct Access-Control-Allow-Origin headers

var $c = $('.control');

var isLoaded = false;

var $d = $('.drop');

if (reverse) {

var tmp = minY;

minY = maxY;

maxY = tmp;

}

$c.click(function(e) {

e.preventDefault();

if (!isLoaded) {

if ($c.hasClass('loading')) {

return;

}

$c.addClass('loading');

eq.play(songUrl, function() {

$c.removeClass('loading').addClass('playing');

isLoaded = true;

});

} else {

if ($c.hasClass('playing')) {

$c.removeClass('playing');

eq.stopSound();

} else {

$c.addClass('playing');

eq.replaySound();

}

}

});

var offsets = [];

function doRender() {

requestAnimationFrame(doRender);

$d.each(function(i) {

if (offsetBalls) {

if (i % 2 != 0) {

i = Math.ceil($d.length / 2) + (i - 1) / 2;

} else {

i /= 2;

}

}

if (typeof offsets[i] == 'undefined') {

offsets[i] = 0;

}

var a = eq.getSpectrumByPercentage((i + 0) / ($d.length)) / 255;

if ($c.hasClass('playing')) {

offsets[i] = a * (1 - smoothFac) + offsets[i] * smoothFac;

} else {

a = pausePosition;

offsets[i] = a * (1 - smoothFacPause) + offsets[i] * smoothFacPause;

}

var y = minY - (minY - maxY) * offsets[i];

$(this).css('transform', 'translateY(' + y + 'px)');

});

}

//this part below is taken and modified from Jaakko Alajoki's pen #rVPGBe

var Equalizer = new Function();

if (!window.AudioContext) {

if (!window.webkitAudioContext) {

alert('no audiocontext found');

}

window.AudioContext = window.webkitAudioContext;

}

Equalizer.prototype.context = new AudioContext();

Equalizer.prototype.audioBuffer = [];

Equalizer.prototype.sourceNode = {};

Equalizer.prototype.analyser = {};

Equalizer.prototype.javascriptNode = {};

Equalizer.prototype.audioData = [];

Equalizer.prototype.fftSize = 512;

Equalizer.prototype.playStart = 0;

Equalizer.prototype.playResume = 0;

Equalizer.prototype.buffer = [];

Equalizer.prototype.play = function(url, loadCallback) {

var self = this;

this.javascriptNode = this.context.createScriptProcessor(2048, 1, 1);

this.javascriptNode.connect(this.context.destination);

this.javascriptNode.onaudioprocess = function() {

self.processAudio();

};

this.analyser = this.context.createAnalyser();

this.analyser.smoothingTimeConstant = 0.2;

this.analyser.fftSize = this.fftSize;

this.sourceNode = this.context.createBufferSource();

this.sourceNode.connect(this.analyser);

this.analyser.connect(this.javascriptNode);

this.sourceNode.connect(this.context.destination);

var request = new XMLHttpRequest();

request.open('GET', url, true);

request.responseType = 'arraybuffer';

request.onload = function() {

self.context.decodeAudioData(request.response, function(buffer) {

self.buffer = buffer;

self.playSound(buffer);

if (typeof(loadCallback) !== "undefined") {

loadCallback();

}

});

}

request.send();

}

Equalizer.prototype.playSound = function(buffer) {

this.sourceNode.buffer = buffer;

this.sourceNode.loop = true;

this.sourceNode.start(0);

this.playStart = new Date().getTime();

}

Equalizer.prototype.stopSound = function() {

this.playResume = new Date().getTime();

this.playResume -= this.playStart;

this.playResume /= 1000;

this.playResume %= this.sourceNode.buffer.duration;

this.sourceNode.stop();

}

Equalizer.prototype.replaySound = function() {

this.sourceNode = this.context.createBufferSource();

this.sourceNode.connect(this.analyser);

this.sourceNode.connect(this.context.destination);

this.sourceNode.buffer = this.buffer;

this.sourceNode.loop = true;

this.sourceNode.start(0, this.playResume);

this.playStart = new Date().getTime() - this.playResume * 1000;

}

Equalizer.prototype.processAudio = function() {

this.audioData = new Uint8Array(this.analyser.frequencyBinCount);

this.analyser.getByteFrequencyData(this.audioData);

}

Equalizer.prototype.getSpectrum = function() {

return this.audioData;

}

Equalizer.prototype.getSpectrumAt = function(i) {

return typeof(this.audioData[i]) !== "undefined" ? this.audioData[i] : 0;

}

Equalizer.prototype.getSpectrumByPercentage = function(p) {

var modLength = this.audioData.length - Math.floor(cutoffLow * this.audioData.length + cutoffHigh * this.audioData.length);

var i = Math.floor(p * modLength + cutoffLow * this.audioData.length);

return typeof(this.audioData[i]) !== "undefined" ? this.audioData[i] : 0;

}

var eq = new Equalizer();

doRender();