CRT風ポストエフェクトを追加してみる

公開:2017-04-16 18:06
更新:2017-11-15 21:58
カテゴリ:シューティングゲーム,ゲーム製作

Shader Toyのコードを拝借して若干手を加え、CRT風ポストエフェクトを追加してみた。比較のために画面の右半分だけにエフェクトを追加している。

元のポストエフェクトのコードは以下。

https://www.shadertoy.com/view/4scSR8

なかなかレトロな雰囲気を醸し出してよい。元コードはCRTっぽく湾曲して表示するエフェクトもあった(warp())が、それは適用していない。

ポストエフェクトはthree.jsのexampleにあるEffectComposerというのを使っている。 Passを継承したクラスにシェーダーコードを書いて、それをEffectComposerに追加していくと、エフェクトがチェインされ、実行される。いくつかのPassもexampleに入っているので、それを参考にすれば比較的簡単にポストエフェクトを書くことができる。

ちなみに今回作成したPassは下記。シェーダーコードはShaderToyのものをほぼそのまま使わせてもらっている。 ただShaderToyのみで使える変数があったりするので、three.js上で動くように修正する必要はある。

/**
 * @author SFPGMR
 */
// Shader Toyより拝借して少し改造
// https://www.shadertoy.com/view/4scSR8
// by Timothy Lottes
//
"use strict";

let vertexShader =
  `
varying vec2 vUv;
void main()    {
        vUv = uv;
    gl_Position = vec4( position, 1.0 );
  }
`;
let fragmentShader =
  `
uniform sampler2D tDiffuse;
uniform vec2 resolution;
uniform float time;
varying vec2 vUv;

#define RGBA(r, g, b, a)    vec4(float(r)/255.0, float(g)/255.0, float(b)/255.0, float(a)/255.0)

//const vec3 kBackgroundColor = RGBA(0x00, 0x00, 0x00, 0x00).rgb; // medium-blue sky
const vec3 kBackgroundColor = RGBA(0xff, 0x00, 0xff, 0xff).rgb; // test magenta

// Emulated input resolution.
// Fix resolution to set amount.
// Note: 256x224 is the most common resolution of the SNES, and that of Super Mario World.
vec2 res = vec2(
  640.0 / 1.0,
  480.0 / 1.0
);

// Hardness of scanline.
//    -8.0 = soft
// -16.0 = medium
float sHardScan = -8.0;

// Hardness of pixels in scanline.
// -2.0 = soft
// -4.0 = hard
const float kHardPix = -3.0;

// Display warp.
// 0.0 = none
// 1.0 / 8.0 = extreme
const vec2 kWarp = vec2(1.0 / 32.0, 1.0 / 24.0);
//const vec2 kWarp = vec2(0);

// Amount of shadow mask.
float kMaskDark = 0.5;
float kMaskLight = 1.5;

//------------------------------------------------------------------------

// sRGB to Linear.
// Assuing using sRGB typed textures this should not be needed.
float toLinear1(float c) {
    return (c <= 0.04045) ?
        (c / 12.92) :
        pow((c + 0.055) / 1.055, 2.4);
}
vec3 toLinear(vec3 c) {
    return vec3(toLinear1(c.r), toLinear1(c.g), toLinear1(c.b));
}

// Linear to sRGB.
// Assuing using sRGB typed textures this should not be needed.
float toSrgb1(float c) {
    return(c < 0.0031308 ?
        (c * 12.92) :
        (1.055 * pow(c, 0.41666) - 0.055));
}
vec3 toSrgb(vec3 c) {
    return vec3(toSrgb1(c.r), toSrgb1(c.g), toSrgb1(c.b));
}

// Nearest emulated sample given floating point position and texel offset.
// Also zero's off screen.
vec4 fetch(vec2 pos, vec2 off)
{
    pos = floor(pos * res + off) / res;
    if (max(abs(pos.x - 0.5), abs(pos.y - 0.5)) > 0.5)
        return vec4(vec3(0.0), 0.0);

//    vec4 sampledColor = texture(iChannel0, pos.xy, -16.0);
    vec4 sampledColor = texture2D(tDiffuse, pos.xy, -16.0);

    sampledColor = vec4(
        (sampledColor.rgb * sampledColor.a) +
            (kBackgroundColor * (1.0 - sampledColor.a)),
        1.0
    );

    return vec4(
        toLinear(sampledColor.rgb),
        sampledColor.a
    );
}

// Distance in emulated pixels to nearest texel.
vec2 dist(vec2 pos) {
    pos = pos * res;
    return -((pos - floor(pos)) - vec2(0.5));
}

// 1D Gaussian.
float gaus(float pos, float scale) {
    return exp2(scale * pos * pos);
}

// 3-tap Gaussian filter along horz line.
vec3 horz3(vec2 pos, float off)
{
    vec3 b = fetch(pos, vec2(-1.0, off)).rgb;
    vec3 c = fetch(pos, vec2( 0.0, off)).rgb;
    vec3 d = fetch(pos, vec2(+1.0, off)).rgb;
    float dst = dist(pos).x;
    // Convert distance to weight.
    float scale = kHardPix;
    float wb = gaus(dst - 1.0, scale);
    float wc = gaus(dst + 0.0, scale);
    float wd = gaus(dst + 1.0, scale);
    // Return filtered sample.
    return (b * wb + c * wc + d * wd) / (wb + wc + wd);
}

// 5-tap Gaussian filter along horz line.
vec3 horz5(vec2 pos, float off)
{
    vec3 a = fetch(pos, vec2(-2.0, off)).rgb;
    vec3 b = fetch(pos, vec2(-1.0, off)).rgb;
    vec3 c = fetch(pos, vec2( 0.0, off)).rgb;
    vec3 d = fetch(pos, vec2(+1.0, off)).rgb;
    vec3 e = fetch(pos, vec2(+2.0, off)).rgb;
    float dst = dist(pos).x;
    // Convert distance to weight.
    float scale = kHardPix;
    float wa = gaus(dst - 2.0, scale);
    float wb = gaus(dst - 1.0, scale);
    float wc = gaus(dst + 0.0, scale);
    float wd = gaus(dst + 1.0, scale);
    float we = gaus(dst + 2.0, scale);
    // Return filtered sample.
    return (a * wa + b * wb + c * wc + d * wd + e * we) / (wa + wb + wc + wd + we);
}

// Return scanline weight.
float scan(vec2 pos, float off) {
    float dst = dist(pos).y;
    return gaus(dst + off, sHardScan);
}

// Allow nearest three lines to effect pixel.
vec3 tri(vec2 pos)
{
    vec3 a = horz3(pos, -1.0);
    vec3 b = horz5(pos,  0.0);
    vec3 c = horz3(pos, +1.0);
    float wa = scan(pos, -1.0);
    float wb = scan(pos,  0.0);
    float wc = scan(pos, +1.0);
    return a * wa + b * wb + c * wc;
}

// Distortion of scanlines, and end of screen alpha.
vec2 warp(vec2 pos)
{
    pos = pos * 2.0 - 1.0;
    pos *= vec2(
        1.0 + (pos.y * pos.y) * kWarp.x,
        1.0 + (pos.x * pos.x) * kWarp.y
    );
    return pos * 0.5 + 0.5;
}

// Shadow mask.
vec3 mask(vec2 pos)
{
    pos.x += pos.y * 3.0;
    vec3 mask = vec3(kMaskDark, kMaskDark, kMaskDark);
    pos.x = fract(pos.x / 6.0);
    if (pos.x < 0.333)
        mask.r = kMaskLight;
    else if (pos.x < 0.666)
        mask.g = kMaskLight;
    else
        mask.b = kMaskLight;
    return mask;
}

// Draw dividing bars.
float bar(float pos, float bar) {
    pos -= bar;
    return (pos * pos < 4.0) ? 0.0 : 1.0;
}

float rand(vec2 co) {
    return fract(sin(dot(co.xy , vec2(12.9898, 78.233))) * 43758.5453);
}

// Entry.
void main()
{
//    vec2 pos = warp(gl_FragCoord.xy / resolution.xy);
    vec2 pos = gl_FragCoord.xy / resolution.xy;

      // Unmodified.
    if(gl_FragCoord.x > resolution.x * 0.5){
        vec3 c = tri(pos) * mask(gl_FragCoord.xy);
    gl_FragColor = vec4(
        toSrgb(c),
        1.0
    );
    } else {
      gl_FragColor = texture2D(tDiffuse,vUv);
    }
}
`;

//     let geometry = new THREE.PlaneBufferGeometry( 1920, 1080 );
let uniforms = {
  tDiffuse: { value: null },
  resolution: { value: new THREE.Vector2() },
  time: { value: 0.0 }
};
//     uniforms.resolution.value.x = WIDTH;
//     uniforms.resolution.value.y = HEIGHT;
//     let material = new THREE.ShaderMaterial( {
//       uniforms: uniforms,
//       vertexShader: vertShader,
//       fragmentShader: fragShader
//     } );
//     let mesh = new THREE.Mesh( geometry, material );
//     mesh.position.z = -5000;
//     scene.add( mesh );
//   }

export default class SFCrtShaderPass extends THREE.Pass {
  constructor(width, height) {
    super();

    this.uniforms = THREE.UniformsUtils.clone(uniforms);
    this.uniforms.resolution.value.x = width;
    this.uniforms.resolution.value.y = height;
    this.material = new THREE.ShaderMaterial({
      uniforms: this.uniforms,
      vertexShader: vertexShader,
      fragmentShader: fragmentShader
    });

    this.camera = new THREE.OrthographicCamera(- 1, 1, 1, - 1, 0, 1);
    this.scene = new THREE.Scene();

    this.quad = new THREE.Mesh(new THREE.PlaneBufferGeometry(2, 2), null);
    this.scene.add(this.quad);

  }

  setSize(width, height) {
    this.uniforms.resolution.value.x = width;
    this.uniforms.resolution.value.y = height;
  }

  render(renderer, writeBuffer, readBuffer, delta, maskActive) {
    this.uniforms["tDiffuse"].value = readBuffer.texture;
    this.quad.material = this.material;

    if (this.renderToScreen) {

      renderer.render(this.scene, this.camera);

    } else {

      renderer.render(this.scene, this.camera, writeBuffer, this.clear);

    }

  }
}

動作サンプル

新しいウィンドウで開く

ソースコード・リソース

/dev/2dshooting2/devver/20170416/css/style.css

    * {
      font-family: 'Meiryo';
      font-size:12px;
    }
    .content {
      width: 100%;
      height: 100%;
      margin-left: auto;
      margin-right: auto;
      margin-top: 0;
      margin-bottom: 0;
      padding: 0;
      border: 0;
      display: -webkit-flex;
      display: -ms-flexbox;
      display: -webkit-box;
      display: flex;
      -webkit-flex-direction: row;
      -ms-flex-direction: row;
      flex-direction: row;
      -webkit-flex-wrap: nowrap;
          -ms-flex-wrap: nowrap;
              flex-wrap: nowrap;
    }
    .error {
      position: relative;
      margin: 0;
      padding: 0;
      border: 0;
    }
    .errorimg {
      position: absolute;
      left: 0;
      top: 0;
    }
    .errortext {
      position: absolute;
      left: 0;
      top: 0;
      background-color: #505050;
      background-color: rgba(80, 80, 80, 0.7);
      color: white;
    }
    body {
      padding: 0;
      border: 0;
      margin: 0;
    }
    .console {
      display: block;
      text-align: center;
      margin-left: auto;
      margin-right: auto;
      padding: 0;
      border: 0;
    }
    .console-debug {
      text-align: center;
      box-sizing: border-box;
      -webkit-box-sizing: border-box;
      margin-left: 0;
      margin-right: 0;
      padding: 0;
      border: 0;
    }
    .info-display {
      position: absolute;
    }
    #input-area:focus,
    #input-area:invalid,
    #input-area:valid,
    #input-area:out-of-range {
      position: absolute;
      top: 200px;
      left: 150px;
      width: 100px;
      height: 20px;
      border: 0;
      color: #000000;
      color: rgba(0, 0, 0, 0.0);
      background: rgba(0, 0, 0, 0);
      outline-color: rgba(0, 0, 0, 0);
      text-decoration: none;
      -webkit-text-decoration-color: rgba(0, 0, 0, 0);
              text-decoration-color: rgba(0, 0, 0, 0);
      z-index: -3;
    }
    /* 開発支援ツール*/
    .devtool {
      border: 1px solid black;
      box-sizing: border-box;
      -webkit-box-sizing: border-box;
      margin: 0;
      padding: 0;
      -webkit-flex-grow: 1;
      -ms-flex-positive: 1;
          flex-grow: 1; 
    }
    /* メニュー */
    .devtool ul.menu {
      background:#303030;
      color:white;
      display: -webkit-flex;
      display: -ms-flexbox;
      display: -webkit-box;
      display: flex;
      -webkit-flex-direction: row;
      -ms-flex-direction: row;
      flex-direction: row;
      -webkit-flex-wrap: nowrap;
          -ms-flex-wrap: nowrap;
              flex-wrap: nowrap;
      list-style-type: none;
      margin:0;
      padding:0;
}
    .devtool ul.menu li {
      border-left: 1px solid black;
      /*flex-grow: 1;*/
      -ms-flex-preferred-size: 100px;
          -webkit-flex-basis: 100px;
              flex-basis: 100px;
      background:#505050;
      text-align: center;
      color:white;
}
    .devtool ul.menu li.active {
      background: white;
      color:black;
}
    .devtool ul.menu li:hover {
      color:red;
      cursor: pointer;
}
    /* ul.menu */
    .devtool .controller {
      margin:10px;
}
    .devtool .controller button {
      border:1px;
      width:50px;
      height:30px;
}
    .devtool .controller button:hover {
      background:red;
}
    .devtool .controller button.play:before {
      content: '➤';
}
    .devtool .controller button.pause:before {
      content: '||';
}
    .devtool .controller button.stop:before {
      content: '■'
}
    .devtool #enemy.controller textarea {
      width: 98%;
      font-size:12px;
}
    .devtool #enemy.controller textarea.formdata {}
    .devtool .formation-editor,.devtool .movseq-editor {
      width:95%;
      font-size:10px;
}
    .devtool .formation-editor table, .devtool .movseq-editor table {
      border-collapse: collapse;
      border:1px solid gray;
      width:100%;
      height:120px;
      margin:5px;
}
    .devtool .formation-editor table tr.selected, .devtool .movseq-editor table tr.selected {
      background-color:pink;
}
    .devtool .formation-editor table th, .devtool .movseq-editor table th {
      color:white;
      background-color: #505050;
      width:50px;
}
    .devtool .formation-editor table td, .devtool .movseq-editor table td {
      text-align:right;
      border:1px solid gray;
}
    
    

/dev/2dshooting2/devver/20170416/data/building.json

/dev/2dshooting2/devver/20170416/data/bullet.json

/dev/2dshooting2/devver/20170416/data/enemyFormationPattern.json

/dev/2dshooting2/devver/20170416/data/enemyMovePattern.json

/dev/2dshooting2/devver/20170416/data/myship.json

/dev/2dshooting2/devver/20170416/data/myship2.json

/dev/2dshooting2/devver/20170416/data/test.json

/dev/2dshooting2/devver/20170416/index.html

<!DOCTYPE html>
<html>
<head>
  <title>Galaxy Fight Game</title>
  <meta name="keywords" content="WebGL,HTML5,three.js" />
  <meta name="description" content="WebGL,HTML5,three.js" />
  <meta charset="UTF-8">
  <link rel="stylesheet" type="text/css" href="./css/style.css">
  <script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/d3/3.5.12/d3.min.js"></script>
  <script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/three.js/87/three.min.js"></script>
  <script src="//threejs.org/examples/js/shaders/CopyShader.js"></script>
  <script src="//threejs.org/examples/js/postprocessing/EffectComposer.js"></script>
  <script src="//threejs.org/examples/js/postprocessing/RenderPass.js"></script>
  <script src="//threejs.org/examples/js/postprocessing/MaskPass.js"></script>
  <script src="//threejs.org/examples/js/postprocessing/ShaderPass.js"></script>
  <script type="text/javascript" src="//threejs.org/examples/js/Detector.js"></script>
<script type="text/javascript" src="//threejs.org/examples/js/libs/stats.min.js"></script>
  <!--<script type="text/javascript" src="//localhost:8081/socket.io/socket.io.js"></script>-->
  <!-- <script type="text/javascript" src="http://www.sfpgmr.net:8081/socket.io/socket.io.js"></script> -->
  <script type="text/javascript" src="./js/dsp.js"></script>
  <script type="text/javascript" src="./js/bundle.js"></script>
  <script type="text/javascript">
    if (!window.location.hostname.match(/localhost/)) {
        (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
        (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
        m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
        })(window,document,'script','https://www.google-analytics.com/analytics.js','ga');

        ga('create', 'UA-15457703-9', 'auto');
        ga('send', 'pageview');
    }
</script>

</head>

<body id="body">
  <div id="content" class="content"></div>
</body>

</html>

/dev/2dshooting2/devver/20170416/js/bundle.js

/dev/2dshooting2/devver/20170416/js/dsp.js

/* 
 *  DSP.js - a comprehensive digital signal processing  library for javascript
 * 
 *  Created by Corban Brook <corbanbrook@gmail.com> on 2010-01-01.
 *  Copyright 2010 Corban Brook. All rights reserved.
 *
 */

////////////////////////////////////////////////////////////////////////////////
//                                  CONSTANTS                                 //
////////////////////////////////////////////////////////////////////////////////

/**
 * DSP is an object which contains general purpose utility functions and constants
 */
var DSP = {
  // Channels
  LEFT:           0,
  RIGHT:          1,
  MIX:            2,

  // Waveforms
  SINE:           1,
  TRIANGLE:       2,
  SAW:            3,
  SQUARE:         4,

  // Filters
  LOWPASS:        0,
  HIGHPASS:       1,
  BANDPASS:       2,
  NOTCH:          3,

  // Window functions
  BARTLETT:       1,
  BARTLETTHANN:   2,
  BLACKMAN:       3,
  COSINE:         4,
  GAUSS:          5,
  HAMMING:        6,
  HANN:           7,
  LANCZOS:        8,
  RECTANGULAR:    9,
  TRIANGULAR:     10,

  // Loop modes
  OFF:            0,
  FW:             1,
  BW:             2,
  FWBW:           3,

  // Math
  TWO_PI:         2*Math.PI
};

// Setup arrays for platforms which do not support byte arrays
function setupTypedArray(name, fallback) {
  // check if TypedArray exists
  // typeof on Minefield and Chrome return function, typeof on Webkit returns object.
  if (typeof this[name] !== "function" && typeof this[name] !== "object") {
    // nope.. check if WebGLArray exists
    if (typeof this[fallback] === "function" && typeof this[fallback] !== "object") {
      this[name] = this[fallback];
    } else {
      // nope.. set as Native JS array
      this[name] = function(obj) {
        if (obj instanceof Array) {
          return obj;
        } else if (typeof obj === "number") {
          return new Array(obj);
        }
      };
    }
  }
}

setupTypedArray("Float32Array", "WebGLFloatArray");
setupTypedArray("Int32Array",   "WebGLIntArray");
setupTypedArray("Uint16Array",  "WebGLUnsignedShortArray");
setupTypedArray("Uint8Array",   "WebGLUnsignedByteArray");


////////////////////////////////////////////////////////////////////////////////
//                            DSP UTILITY FUNCTIONS                           //
////////////////////////////////////////////////////////////////////////////////

/**
 * Inverts the phase of a signal
 *
 * @param {Array} buffer A sample buffer
 *
 * @returns The inverted sample buffer
 */
DSP.invert = function(buffer) {
  for (var i = 0, len = buffer.length; i < len; i++) {
    buffer[i] *= -1;
  }

  return buffer;
};

/**
 * Converts split-stereo (dual mono) sample buffers into a stereo interleaved sample buffer
 *
 * @param {Array} left  A sample buffer
 * @param {Array} right A sample buffer
 *
 * @returns The stereo interleaved buffer
 */
DSP.interleave = function(left, right) {
  if (left.length !== right.length) {
    throw "Can not interleave. Channel lengths differ.";
  }
 
  var stereoInterleaved = new Float32Array(left.length * 2);
 
  for (var i = 0, len = left.length; i < len; i++) {
    stereoInterleaved[2*i]   = left[i];
    stereoInterleaved[2*i+1] = right[i];
  }
 
  return stereoInterleaved;
};

/**
 * Converts a stereo-interleaved sample buffer into split-stereo (dual mono) sample buffers
 *
 * @param {Array} buffer A stereo-interleaved sample buffer
 *
 * @returns an Array containing left and right channels
 */
DSP.deinterleave = (function() {
  var left, right, mix, deinterleaveChannel = []; 

  deinterleaveChannel[DSP.MIX] = function(buffer) {
    for (var i = 0, len = buffer.length/2; i < len; i++) {
      mix[i] = (buffer[2*i] + buffer[2*i+1]) / 2;
    }
    return mix;
  };

  deinterleaveChannel[DSP.LEFT] = function(buffer) {
    for (var i = 0, len = buffer.length/2; i < len; i++) {
      left[i]  = buffer[2*i];
    }
    return left;
  };

  deinterleaveChannel[DSP.RIGHT] = function(buffer) {
    for (var i = 0, len = buffer.length/2; i < len; i++) {
      right[i]  = buffer[2*i+1];
    }
    return right;
  };

  return function(channel, buffer) { 
    left  = left  || new Float32Array(buffer.length/2);
    right = right || new Float32Array(buffer.length/2);
    mix   = mix   || new Float32Array(buffer.length/2);

    if (buffer.length/2 !== left.length) {
      left  = new Float32Array(buffer.length/2);
      right = new Float32Array(buffer.length/2);
      mix   = new Float32Array(buffer.length/2);
    }

    return deinterleaveChannel[channel](buffer);
  };
}());

/**
 * Separates a channel from a stereo-interleaved sample buffer
 *
 * @param {Array}  buffer A stereo-interleaved sample buffer
 * @param {Number} channel A channel constant (LEFT, RIGHT, MIX)
 *
 * @returns an Array containing a signal mono sample buffer
 */
DSP.getChannel = DSP.deinterleave;

/**
 * Helper method (for Reverb) to mix two (interleaved) samplebuffers. It's possible
 * to negate the second buffer while mixing and to perform a volume correction
 * on the final signal.
 *
 * @param {Array} sampleBuffer1 Array containing Float values or a Float32Array
 * @param {Array} sampleBuffer2 Array containing Float values or a Float32Array
 * @param {Boolean} negate When true inverts/flips the audio signal
 * @param {Number} volumeCorrection When you add multiple sample buffers, use this to tame your signal ;)
 *
 * @returns A new Float32Array interleaved buffer.
 */
DSP.mixSampleBuffers = function(sampleBuffer1, sampleBuffer2, negate, volumeCorrection){
  var outputSamples = new Float32Array(sampleBuffer1);

  for(var i = 0; i<sampleBuffer1.length; i++){
    outputSamples[i] += (negate ? -sampleBuffer2[i] : sampleBuffer2[i]) / volumeCorrection;
  }
 
  return outputSamples;
}; 

// Biquad filter types
DSP.LPF = 0;                // H(s) = 1 / (s^2 + s/Q + 1)
DSP.HPF = 1;                // H(s) = s^2 / (s^2 + s/Q + 1)
DSP.BPF_CONSTANT_SKIRT = 2; // H(s) = s / (s^2 + s/Q + 1)  (constant skirt gain, peak gain = Q)
DSP.BPF_CONSTANT_PEAK = 3;  // H(s) = (s/Q) / (s^2 + s/Q + 1)      (constant 0 dB peak gain)
DSP.NOTCH = 4;              // H(s) = (s^2 + 1) / (s^2 + s/Q + 1)
DSP.APF = 5;                // H(s) = (s^2 - s/Q + 1) / (s^2 + s/Q + 1)
DSP.PEAKING_EQ = 6;         // H(s) = (s^2 + s*(A/Q) + 1) / (s^2 + s/(A*Q) + 1)
DSP.LOW_SHELF = 7;          // H(s) = A * (s^2 + (sqrt(A)/Q)*s + A)/(A*s^2 + (sqrt(A)/Q)*s + 1)
DSP.HIGH_SHELF = 8;         // H(s) = A * (A*s^2 + (sqrt(A)/Q)*s + 1)/(s^2 + (sqrt(A)/Q)*s + A)

// Biquad filter parameter types
DSP.Q = 1;
DSP.BW = 2; // SHARED with BACKWARDS LOOP MODE
DSP.S = 3;

// Find RMS of signal
DSP.RMS = function(buffer) {
  var total = 0;
  
  for (var i = 0, n = buffer.length; i < n; i++) {
    total += buffer[i] * buffer[i];
  }
  
  return Math.sqrt(total / n);
};

// Find Peak of signal
DSP.Peak = function(buffer) {
  var peak = 0;
  
  for (var i = 0, n = buffer.length; i < n; i++) {
    peak = (Math.abs(buffer[i]) > peak) ? Math.abs(buffer[i]) : peak; 
  }
  
  return peak;
};

// Fourier Transform Module used by DFT, FFT, RFFT
function FourierTransform(bufferSize, sampleRate) {
  this.bufferSize = bufferSize;
  this.sampleRate = sampleRate;
  this.bandwidth  = 2 / bufferSize * sampleRate / 2;

  this.spectrum   = new Float32Array(bufferSize/2);
  this.real       = new Float32Array(bufferSize);
  this.imag       = new Float32Array(bufferSize);

  this.peakBand   = 0;
  this.peak       = 0;

  /**
   * Calculates the *middle* frequency of an FFT band.
   *
   * @param {Number} index The index of the FFT band.
   *
   * @returns The middle frequency in Hz.
   */
  this.getBandFrequency = function(index) {
    return this.bandwidth * index + this.bandwidth / 2;
  };

  this.calculateSpectrum = function() {
    var spectrum  = this.spectrum,
        real      = this.real,
        imag      = this.imag,
        bSi       = 2 / this.bufferSize,
        sqrt      = Math.sqrt,
        rval, 
        ival,
        mag;

    for (var i = 0, N = bufferSize/2; i < N; i++) {
      rval = real[i];
      ival = imag[i];
      mag = bSi * sqrt(rval * rval + ival * ival);

      if (mag > this.peak) {
        this.peakBand = i;
        this.peak = mag;
      }

      spectrum[i] = mag;
    }
  };
}

/**
 * DFT is a class for calculating the Discrete Fourier Transform of a signal.
 *
 * @param {Number} bufferSize The size of the sample buffer to be computed
 * @param {Number} sampleRate The sampleRate of the buffer (eg. 44100)
 *
 * @constructor
 */
function DFT(bufferSize, sampleRate) {
  FourierTransform.call(this, bufferSize, sampleRate);

  var N = bufferSize/2 * bufferSize;
  var TWO_PI = 2 * Math.PI;

  this.sinTable = new Float32Array(N);
  this.cosTable = new Float32Array(N);

  for (var i = 0; i < N; i++) {
    this.sinTable[i] = Math.sin(i * TWO_PI / bufferSize);
    this.cosTable[i] = Math.cos(i * TWO_PI / bufferSize);
  }
}

/**
 * Performs a forward transform on the sample buffer.
 * Converts a time domain signal to frequency domain spectra.
 *
 * @param {Array} buffer The sample buffer
 *
 * @returns The frequency spectrum array
 */
DFT.prototype.forward = function(buffer) {
  var real = this.real, 
      imag = this.imag,
      rval,
      ival;

  for (var k = 0; k < this.bufferSize/2; k++) {
    rval = 0.0;
    ival = 0.0;

    for (var n = 0; n < buffer.length; n++) {
      rval += this.cosTable[k*n] * buffer[n];
      ival += this.sinTable[k*n] * buffer[n];
    }

    real[k] = rval;
    imag[k] = ival;
  }

  return this.calculateSpectrum();
};


/**
 * FFT is a class for calculating the Discrete Fourier Transform of a signal
 * with the Fast Fourier Transform algorithm.
 *
 * @param {Number} bufferSize The size of the sample buffer to be computed. Must be power of 2
 * @param {Number} sampleRate The sampleRate of the buffer (eg. 44100)
 *
 * @constructor
 */
function FFT(bufferSize, sampleRate) {
  FourierTransform.call(this, bufferSize, sampleRate);
   
  this.reverseTable = new Uint32Array(bufferSize);

  var limit = 1;
  var bit = bufferSize >> 1;

  var i;

  while (limit < bufferSize) {
    for (i = 0; i < limit; i++) {
      this.reverseTable[i + limit] = this.reverseTable[i] + bit;
    }

    limit = limit << 1;
    bit = bit >> 1;
  }

  this.sinTable = new Float32Array(bufferSize);
  this.cosTable = new Float32Array(bufferSize);

  for (i = 0; i < bufferSize; i++) {
    this.sinTable[i] = Math.sin(-Math.PI/i);
    this.cosTable[i] = Math.cos(-Math.PI/i);
  }
}

/**
 * Performs a forward transform on the sample buffer.
 * Converts a time domain signal to frequency domain spectra.
 *
 * @param {Array} buffer The sample buffer. Buffer Length must be power of 2
 *
 * @returns The frequency spectrum array
 */
FFT.prototype.forward = function(buffer) {
  // Locally scope variables for speed up
  var bufferSize      = this.bufferSize,
      cosTable        = this.cosTable,
      sinTable        = this.sinTable,
      reverseTable    = this.reverseTable,
      real            = this.real,
      imag            = this.imag,
      spectrum        = this.spectrum;

  var k = Math.floor(Math.log(bufferSize) / Math.LN2);

  if (Math.pow(2, k) !== bufferSize) { throw "Invalid buffer size, must be a power of 2."; }
  if (bufferSize !== buffer.length)  { throw "Supplied buffer is not the same size as defined FFT. FFT Size: " + bufferSize + " Buffer Size: " + buffer.length; }

  var halfSize = 1,
      phaseShiftStepReal,
      phaseShiftStepImag,
      currentPhaseShiftReal,
      currentPhaseShiftImag,
      off,
      tr,
      ti,
      tmpReal,
      i;

  for (i = 0; i < bufferSize; i++) {
    real[i] = buffer[reverseTable[i]];
    imag[i] = 0;
  }

  while (halfSize < bufferSize) {
    //phaseShiftStepReal = Math.cos(-Math.PI/halfSize);
    //phaseShiftStepImag = Math.sin(-Math.PI/halfSize);
    phaseShiftStepReal = cosTable[halfSize];
    phaseShiftStepImag = sinTable[halfSize];
    
    currentPhaseShiftReal = 1;
    currentPhaseShiftImag = 0;

    for (var fftStep = 0; fftStep < halfSize; fftStep++) {
      i = fftStep;

      while (i < bufferSize) {
        off = i + halfSize;
        tr = (currentPhaseShiftReal * real[off]) - (currentPhaseShiftImag * imag[off]);
        ti = (currentPhaseShiftReal * imag[off]) + (currentPhaseShiftImag * real[off]);

        real[off] = real[i] - tr;
        imag[off] = imag[i] - ti;
        real[i] += tr;
        imag[i] += ti;

        i += halfSize << 1;
      }

      tmpReal = currentPhaseShiftReal;
      currentPhaseShiftReal = (tmpReal * phaseShiftStepReal) - (currentPhaseShiftImag * phaseShiftStepImag);
      currentPhaseShiftImag = (tmpReal * phaseShiftStepImag) + (currentPhaseShiftImag * phaseShiftStepReal);
    }

    halfSize = halfSize << 1;
  }

  return this.calculateSpectrum();
};

FFT.prototype.inverse = function(real, imag) {
  // Locally scope variables for speed up
  var bufferSize      = this.bufferSize,
      cosTable        = this.cosTable,
      sinTable        = this.sinTable,
      reverseTable    = this.reverseTable,
      spectrum        = this.spectrum;
     
      real = real || this.real;
      imag = imag || this.imag;

  var halfSize = 1,
      phaseShiftStepReal,
      phaseShiftStepImag,
      currentPhaseShiftReal,
      currentPhaseShiftImag,
      off,
      tr,
      ti,
      tmpReal,
      i;

  for (i = 0; i < bufferSize; i++) {
    imag[i] *= -1;
  }

  var revReal = new Float32Array(bufferSize);
  var revImag = new Float32Array(bufferSize);
 
  for (i = 0; i < real.length; i++) {
    revReal[i] = real[reverseTable[i]];
    revImag[i] = imag[reverseTable[i]];
  }
 
  real = revReal;
  imag = revImag;

  while (halfSize < bufferSize) {
    phaseShiftStepReal = cosTable[halfSize];
    phaseShiftStepImag = sinTable[halfSize];
    currentPhaseShiftReal = 1;
    currentPhaseShiftImag = 0;

    for (var fftStep = 0; fftStep < halfSize; fftStep++) {
      i = fftStep;

      while (i < bufferSize) {
        off = i + halfSize;
        tr = (currentPhaseShiftReal * real[off]) - (currentPhaseShiftImag * imag[off]);
        ti = (currentPhaseShiftReal * imag[off]) + (currentPhaseShiftImag * real[off]);

        real[off] = real[i] - tr;
        imag[off] = imag[i] - ti;
        real[i] += tr;
        imag[i] += ti;

        i += halfSize << 1;
      }

      tmpReal = currentPhaseShiftReal;
      currentPhaseShiftReal = (tmpReal * phaseShiftStepReal) - (currentPhaseShiftImag * phaseShiftStepImag);
      currentPhaseShiftImag = (tmpReal * phaseShiftStepImag) + (currentPhaseShiftImag * phaseShiftStepReal);
    }

    halfSize = halfSize << 1;
  }

  var buffer = new Float32Array(bufferSize); // this should be reused instead
  for (i = 0; i < bufferSize; i++) {
    buffer[i] = real[i] / bufferSize;
  }

  return buffer;
};

/**
 * RFFT is a class for calculating the Discrete Fourier Transform of a signal
 * with the Fast Fourier Transform algorithm.
 *
 * This method currently only contains a forward transform but is highly optimized.
 *
 * @param {Number} bufferSize The size of the sample buffer to be computed. Must be power of 2
 * @param {Number} sampleRate The sampleRate of the buffer (eg. 44100)
 *
 * @constructor
 */

// lookup tables don't really gain us any speed, but they do increase
// cache footprint, so don't use them in here

// also we don't use sepearate arrays for real/imaginary parts

// this one a little more than twice as fast as the one in FFT
// however I only did the forward transform

// the rest of this was translated from C, see http://www.jjj.de/fxt/
// this is the real split radix FFT

function RFFT(bufferSize, sampleRate) {
  FourierTransform.call(this, bufferSize, sampleRate);

  this.trans = new Float32Array(bufferSize);

  this.reverseTable = new Uint32Array(bufferSize);

  // don't use a lookup table to do the permute, use this instead
  this.reverseBinPermute = function (dest, source) {
    var bufferSize  = this.bufferSize, 
        halfSize    = bufferSize >>> 1, 
        nm1         = bufferSize - 1, 
        i = 1, r = 0, h;

    dest[0] = source[0];

    do {
      r += halfSize;
      dest[i] = source[r];
      dest[r] = source[i];
      
      i++;

      h = halfSize << 1;
      while (h = h >> 1, !((r ^= h) & h));

      if (r >= i) { 
        dest[i]     = source[r]; 
        dest[r]     = source[i];

        dest[nm1-i] = source[nm1-r]; 
        dest[nm1-r] = source[nm1-i];
      }
      i++;
    } while (i < halfSize);
    dest[nm1] = source[nm1];
  };

  this.generateReverseTable = function () {
    var bufferSize  = this.bufferSize, 
        halfSize    = bufferSize >>> 1, 
        nm1         = bufferSize - 1, 
        i = 1, r = 0, h;

    this.reverseTable[0] = 0;

    do {
      r += halfSize;
      
      this.reverseTable[i] = r;
      this.reverseTable[r] = i;

      i++;

      h = halfSize << 1;
      while (h = h >> 1, !((r ^= h) & h));

      if (r >= i) { 
        this.reverseTable[i] = r;
        this.reverseTable[r] = i;

        this.reverseTable[nm1-i] = nm1-r;
        this.reverseTable[nm1-r] = nm1-i;
      }
      i++;
    } while (i < halfSize);

    this.reverseTable[nm1] = nm1;
  };

  this.generateReverseTable();
}


// Ordering of output:
//
// trans[0]     = re[0] (==zero frequency, purely real)
// trans[1]     = re[1]
//             ...
// trans[n/2-1] = re[n/2-1]
// trans[n/2]   = re[n/2]    (==nyquist frequency, purely real)
//
// trans[n/2+1] = im[n/2-1]
// trans[n/2+2] = im[n/2-2]
//             ...
// trans[n-1]   = im[1] 

RFFT.prototype.forward = function(buffer) {
  var n         = this.bufferSize, 
      spectrum  = this.spectrum,
      x         = this.trans, 
      TWO_PI    = 2*Math.PI,
      sqrt      = Math.sqrt,
      i         = n >>> 1,
      bSi       = 2 / n,
      n2, n4, n8, nn, 
      t1, t2, t3, t4, 
      i1, i2, i3, i4, i5, i6, i7, i8, 
      st1, cc1, ss1, cc3, ss3,
      e, 
      a,
      rval, ival, mag; 

  this.reverseBinPermute(x, buffer);

  /*
  var reverseTable = this.reverseTable;

  for (var k = 0, len = reverseTable.length; k < len; k++) {
    x[k] = buffer[reverseTable[k]];
  }
  */

  for (var ix = 0, id = 4; ix < n; id *= 4) {
    for (var i0 = ix; i0 < n; i0 += id) {
      //sumdiff(x[i0], x[i0+1]); // {a, b}  <--| {a+b, a-b}
      st1 = x[i0] - x[i0+1];
      x[i0] += x[i0+1];
      x[i0+1] = st1;
    } 
    ix = 2*(id-1);
  }

  n2 = 2;
  nn = n >>> 1;

  while((nn = nn >>> 1)) {
    ix = 0;
    n2 = n2 << 1;
    id = n2 << 1;
    n4 = n2 >>> 2;
    n8 = n2 >>> 3;
    do {
      if(n4 !== 1) {
        for(i0 = ix; i0 < n; i0 += id) {
          i1 = i0;
          i2 = i1 + n4;
          i3 = i2 + n4;
          i4 = i3 + n4;
     
          //diffsum3_r(x[i3], x[i4], t1); // {a, b, s} <--| {a, b-a, a+b}
          t1 = x[i3] + x[i4];
          x[i4] -= x[i3];
          //sumdiff3(x[i1], t1, x[i3]);   // {a, b, d} <--| {a+b, b, a-b}
          x[i3] = x[i1] - t1; 
          x[i1] += t1;
     
          i1 += n8;
          i2 += n8;
          i3 += n8;
          i4 += n8;
         
          //sumdiff(x[i3], x[i4], t1, t2); // {s, d}  <--| {a+b, a-b}
          t1 = x[i3] + x[i4];
          t2 = x[i3] - x[i4];
         
          t1 = -t1 * Math.SQRT1_2;
          t2 *= Math.SQRT1_2;
     
          // sumdiff(t1, x[i2], x[i4], x[i3]); // {s, d}  <--| {a+b, a-b}
          st1 = x[i2];
          x[i4] = t1 + st1; 
          x[i3] = t1 - st1;
          
          //sumdiff3(x[i1], t2, x[i2]); // {a, b, d} <--| {a+b, b, a-b}
          x[i2] = x[i1] - t2;
          x[i1] += t2;
        }
      } else {
        for(i0 = ix; i0 < n; i0 += id) {
          i1 = i0;
          i2 = i1 + n4;
          i3 = i2 + n4;
          i4 = i3 + n4;
     
          //diffsum3_r(x[i3], x[i4], t1); // {a, b, s} <--| {a, b-a, a+b}
          t1 = x[i3] + x[i4]; 
          x[i4] -= x[i3];
          
          //sumdiff3(x[i1], t1, x[i3]);   // {a, b, d} <--| {a+b, b, a-b}
          x[i3] = x[i1] - t1; 
          x[i1] += t1;
        }
      }
   
      ix = (id << 1) - n2;
      id = id << 2;
    } while (ix < n);
 
    e = TWO_PI / n2;

    for (var j = 1; j < n8; j++) {
      a = j * e;
      ss1 = Math.sin(a);
      cc1 = Math.cos(a);

      //ss3 = sin(3*a); cc3 = cos(3*a);
      cc3 = 4*cc1*(cc1*cc1-0.75);
      ss3 = 4*ss1*(0.75-ss1*ss1);
   
      ix = 0; id = n2 << 1;
      do {
        for (i0 = ix; i0 < n; i0 += id) {
          i1 = i0 + j;
          i2 = i1 + n4;
          i3 = i2 + n4;
          i4 = i3 + n4;
       
          i5 = i0 + n4 - j;
          i6 = i5 + n4;
          i7 = i6 + n4;
          i8 = i7 + n4;
       
          //cmult(c, s, x, y, &u, &v)
          //cmult(cc1, ss1, x[i7], x[i3], t2, t1); // {u,v} <--| {x*c-y*s, x*s+y*c}
          t2 = x[i7]*cc1 - x[i3]*ss1; 
          t1 = x[i7]*ss1 + x[i3]*cc1;
          
          //cmult(cc3, ss3, x[i8], x[i4], t4, t3);
          t4 = x[i8]*cc3 - x[i4]*ss3; 
          t3 = x[i8]*ss3 + x[i4]*cc3;
       
          //sumdiff(t2, t4);   // {a, b} <--| {a+b, a-b}
          st1 = t2 - t4;
          t2 += t4;
          t4 = st1;
          
          //sumdiff(t2, x[i6], x[i8], x[i3]); // {s, d}  <--| {a+b, a-b}
          //st1 = x[i6]; x[i8] = t2 + st1; x[i3] = t2 - st1;
          x[i8] = t2 + x[i6]; 
          x[i3] = t2 - x[i6];
         
          //sumdiff_r(t1, t3); // {a, b} <--| {a+b, b-a}
          st1 = t3 - t1;
          t1 += t3;
          t3 = st1;
          
          //sumdiff(t3, x[i2], x[i4], x[i7]); // {s, d}  <--| {a+b, a-b}
          //st1 = x[i2]; x[i4] = t3 + st1; x[i7] = t3 - st1;
          x[i4] = t3 + x[i2]; 
          x[i7] = t3 - x[i2];
         
          //sumdiff3(x[i1], t1, x[i6]);   // {a, b, d} <--| {a+b, b, a-b}
          x[i6] = x[i1] - t1; 
          x[i1] += t1;
          
          //diffsum3_r(t4, x[i5], x[i2]); // {a, b, s} <--| {a, b-a, a+b}
          x[i2] = t4 + x[i5]; 
          x[i5] -= t4;
        }
     
        ix = (id << 1) - n2;
        id = id << 2;
   
      } while (ix < n);
    }
  }

  while (--i) {
    rval = x[i];
    ival = x[n-i-1];
    mag = bSi * sqrt(rval * rval + ival * ival);

    if (mag > this.peak) {
      this.peakBand = i;
      this.peak = mag;
    }

    spectrum[i] = mag;
  }

  spectrum[0] = bSi * x[0];

  return spectrum;
};

function Sampler(file, bufferSize, sampleRate, playStart, playEnd, loopStart, loopEnd, loopMode) {
  this.file = file;
  this.bufferSize = bufferSize;
  this.sampleRate = sampleRate;
  this.playStart  = playStart || 0; // 0%
  this.playEnd    = playEnd   || 1; // 100%
  this.loopStart  = loopStart || 0;
  this.loopEnd    = loopEnd   || 1;
  this.loopMode   = loopMode  || DSP.OFF;
  this.loaded     = false;
  this.samples    = [];
  this.signal     = new Float32Array(bufferSize);
  this.frameCount = 0;
  this.envelope   = null;
  this.amplitude  = 1;
  this.rootFrequency = 110; // A2 110
  this.frequency  = 550;
  this.step       = this.frequency / this.rootFrequency;
  this.duration   = 0;
  this.samplesProcessed = 0;
  this.playhead   = 0;
 
  var audio = /* new Audio();*/ document.createElement("AUDIO");
  var self = this;
 
  this.loadSamples = function(event) {
    var buffer = DSP.getChannel(DSP.MIX, event.frameBuffer);
    for ( var i = 0; i < buffer.length; i++) {
      self.samples.push(buffer[i]);
    }
  };
 
  this.loadComplete = function() {
    // convert flexible js array into a fast typed array
    self.samples = new Float32Array(self.samples);
    self.loaded = true;
  };
 
  this.loadMetaData = function() {
    self.duration = audio.duration;
  };
 
  audio.addEventListener("MozAudioAvailable", this.loadSamples, false);
  audio.addEventListener("loadedmetadata", this.loadMetaData, false);
  audio.addEventListener("ended", this.loadComplete, false);
  audio.muted = true;
  audio.src = file;
  audio.play();
}

Sampler.prototype.applyEnvelope = function() {
  this.envelope.process(this.signal);
  return this.signal;
};

Sampler.prototype.generate = function() {
  var frameOffset = this.frameCount * this.bufferSize;
 
  var loopWidth = this.playEnd * this.samples.length - this.playStart * this.samples.length;
  var playStartSamples = this.playStart * this.samples.length; // ie 0.5 -> 50% of the length
  var playEndSamples = this.playEnd * this.samples.length; // ie 0.5 -> 50% of the length
  var offset;

  for ( var i = 0; i < this.bufferSize; i++ ) {
    switch (this.loopMode) {
      case DSP.OFF:
        this.playhead = Math.round(this.samplesProcessed * this.step + playStartSamples);
        if (this.playhead < (this.playEnd * this.samples.length) ) {
          this.signal[i] = this.samples[this.playhead] * this.amplitude;
        } else {
          this.signal[i] = 0;
        }
        break;
     
      case DSP.FW:
        this.playhead = Math.round((this.samplesProcessed * this.step) % loopWidth + playStartSamples);
        if (this.playhead < (this.playEnd * this.samples.length) ) {
          this.signal[i] = this.samples[this.playhead] * this.amplitude;
        }
        break;
       
      case DSP.BW:
        this.playhead = playEndSamples - Math.round((this.samplesProcessed * this.step) % loopWidth);
        if (this.playhead < (this.playEnd * this.samples.length) ) {
          this.signal[i] = this.samples[this.playhead] * this.amplitude;
        }
        break;
       
      case DSP.FWBW:
        if ( Math.floor(this.samplesProcessed * this.step / loopWidth) % 2 === 0 ) {
          this.playhead = Math.round((this.samplesProcessed * this.step) % loopWidth + playStartSamples);
        } else {
          this.playhead = playEndSamples - Math.round((this.samplesProcessed * this.step) % loopWidth);
        }  
        if (this.playhead < (this.playEnd * this.samples.length) ) {
          this.signal[i] = this.samples[this.playhead] * this.amplitude;
        }
        break;
    }
    this.samplesProcessed++;
  }

  this.frameCount++;

  return this.signal;
};

Sampler.prototype.setFreq = function(frequency) {
    var totalProcessed = this.samplesProcessed * this.step;
    this.frequency = frequency;
    this.step = this.frequency / this.rootFrequency;
    this.samplesProcessed = Math.round(totalProcessed/this.step);
};

Sampler.prototype.reset = function() {
  this.samplesProcessed = 0;
  this.playhead = 0;
};

/**
 * Oscillator class for generating and modifying signals
 *
 * @param {Number} type       A waveform constant (eg. DSP.SINE)
 * @param {Number} frequency  Initial frequency of the signal
 * @param {Number} amplitude  Initial amplitude of the signal
 * @param {Number} bufferSize Size of the sample buffer to generate
 * @param {Number} sampleRate The sample rate of the signal
 *
 * @contructor
 */
function Oscillator(type, frequency, amplitude, bufferSize, sampleRate) {
  this.frequency  = frequency;
  this.amplitude  = amplitude;
  this.bufferSize = bufferSize;
  this.sampleRate = sampleRate;
  //this.pulseWidth = pulseWidth;
  this.frameCount = 0;
 
  this.waveTableLength = 2048;

  this.cyclesPerSample = frequency / sampleRate;

  this.signal = new Float32Array(bufferSize);
  this.envelope = null;

  switch(parseInt(type, 10)) {
    case DSP.TRIANGLE:
      this.func = Oscillator.Triangle;
      break;

    case DSP.SAW:
      this.func = Oscillator.Saw;
      break;

    case DSP.SQUARE:
      this.func = Oscillator.Square;
      break;

    default:
    case DSP.SINE:
      this.func = Oscillator.Sine;
      break;
  }

  this.generateWaveTable = function() {
    Oscillator.waveTable[this.func] = new Float32Array(2048);
    var waveTableTime = this.waveTableLength / this.sampleRate;
    var waveTableHz = 1 / waveTableTime;

    for (var i = 0; i < this.waveTableLength; i++) {
      Oscillator.waveTable[this.func][i] = this.func(i * waveTableHz/this.sampleRate);
    }
  };

  if ( typeof Oscillator.waveTable === 'undefined' ) {
    Oscillator.waveTable = {};
  }

  if ( typeof Oscillator.waveTable[this.func] === 'undefined' ) {
    this.generateWaveTable();
  }
 
  this.waveTable = Oscillator.waveTable[this.func];
}

/**
 * Set the amplitude of the signal
 *
 * @param {Number} amplitude The amplitude of the signal (between 0 and 1)
 */
Oscillator.prototype.setAmp = function(amplitude) {
  if (amplitude >= 0 && amplitude <= 1) {
    this.amplitude = amplitude;
  } else {
    throw "Amplitude out of range (0..1).";
  }
};
  
/**
 * Set the frequency of the signal
 *
 * @param {Number} frequency The frequency of the signal
 */  
Oscillator.prototype.setFreq = function(frequency) {
  this.frequency = frequency;
  this.cyclesPerSample = frequency / this.sampleRate;
};
     
// Add an oscillator
Oscillator.prototype.add = function(oscillator) {
  for ( var i = 0; i < this.bufferSize; i++ ) {
    //this.signal[i] += oscillator.valueAt(i);
    this.signal[i] += oscillator.signal[i];
  }
 
  return this.signal;
};
     
// Add a signal to the current generated osc signal
Oscillator.prototype.addSignal = function(signal) {
  for ( var i = 0; i < signal.length; i++ ) {
    if ( i >= this.bufferSize ) {
      break;
    }
    this.signal[i] += signal[i];
   
    /*
    // Constrain amplitude
    if ( this.signal[i] > 1 ) {
      this.signal[i] = 1;
    } else if ( this.signal[i] < -1 ) {
      this.signal[i] = -1;
    }
    */
  }
  return this.signal;
};
     
// Add an envelope to the oscillator
Oscillator.prototype.addEnvelope = function(envelope) {
  this.envelope = envelope;
};

Oscillator.prototype.applyEnvelope = function() {
  this.envelope.process(this.signal);
};
     
Oscillator.prototype.valueAt = function(offset) {
  return this.waveTable[offset % this.waveTableLength];
};
     
Oscillator.prototype.generate = function() {
  var frameOffset = this.frameCount * this.bufferSize;
  var step = this.waveTableLength * this.frequency / this.sampleRate;
  var offset;

  for ( var i = 0; i < this.bufferSize; i++ ) {
    //var step = (frameOffset + i) * this.cyclesPerSample % 1;
    //this.signal[i] = this.func(step) * this.amplitude;
    //this.signal[i] = this.valueAt(Math.round((frameOffset + i) * step)) * this.amplitude;
    offset = Math.round((frameOffset + i) * step);
    this.signal[i] = this.waveTable[offset % this.waveTableLength] * this.amplitude;
  }

  this.frameCount++;

  return this.signal;
};

Oscillator.Sine = function(step) {
  return Math.sin(DSP.TWO_PI * step);
};

Oscillator.Square = function(step) {
  return step < 0.5 ? 1 : -1;
};

Oscillator.Saw = function(step) {
  return 2 * (step - Math.round(step));
};

Oscillator.Triangle = function(step) {
  return 1 - 4 * Math.abs(Math.round(step) - step);
};

Oscillator.Pulse = function(step) {
  // stub
};
 
function ADSR(attackLength, decayLength, sustainLevel, sustainLength, releaseLength, sampleRate) {
  this.sampleRate = sampleRate;
  // Length in seconds
  this.attackLength  = attackLength;
  this.decayLength   = decayLength;
  this.sustainLevel  = sustainLevel;
  this.sustainLength = sustainLength;
  this.releaseLength = releaseLength;
  this.sampleRate    = sampleRate;
 
  // Length in samples
  this.attackSamples  = attackLength  * sampleRate;
  this.decaySamples   = decayLength   * sampleRate;
  this.sustainSamples = sustainLength * sampleRate;
  this.releaseSamples = releaseLength * sampleRate;
 
  // Updates the envelope sample positions
  this.update = function() {
    this.attack         =                this.attackSamples;
    this.decay          = this.attack  + this.decaySamples;
    this.sustain        = this.decay   + this.sustainSamples;
    this.release        = this.sustain + this.releaseSamples;
  };
 
  this.update();
 
  this.samplesProcessed = 0;
}

ADSR.prototype.noteOn = function() {
  this.samplesProcessed = 0;
  this.sustainSamples = this.sustainLength * this.sampleRate;
  this.update();
};

// Send a note off when using a sustain of infinity to let the envelope enter the release phase
ADSR.prototype.noteOff = function() {
  this.sustainSamples = this.samplesProcessed - this.decaySamples;
  this.update();
};

ADSR.prototype.processSample = function(sample) {
  var amplitude = 0;

  if ( this.samplesProcessed <= this.attack ) {
    amplitude = 0 + (1 - 0) * ((this.samplesProcessed - 0) / (this.attack - 0));
  } else if ( this.samplesProcessed > this.attack && this.samplesProcessed <= this.decay ) {
    amplitude = 1 + (this.sustainLevel - 1) * ((this.samplesProcessed - this.attack) / (this.decay - this.attack));
  } else if ( this.samplesProcessed > this.decay && this.samplesProcessed <= this.sustain ) {
    amplitude = this.sustainLevel;
  } else if ( this.samplesProcessed > this.sustain && this.samplesProcessed <= this.release ) {
    amplitude = this.sustainLevel + (0 - this.sustainLevel) * ((this.samplesProcessed - this.sustain) / (this.release - this.sustain));
  }
 
  return sample * amplitude;
};

ADSR.prototype.value = function() {
  var amplitude = 0;

  if ( this.samplesProcessed <= this.attack ) {
    amplitude = 0 + (1 - 0) * ((this.samplesProcessed - 0) / (this.attack - 0));
  } else if ( this.samplesProcessed > this.attack && this.samplesProcessed <= this.decay ) {
    amplitude = 1 + (this.sustainLevel - 1) * ((this.samplesProcessed - this.attack) / (this.decay - this.attack));
  } else if ( this.samplesProcessed > this.decay && this.samplesProcessed <= this.sustain ) {
    amplitude = this.sustainLevel;
  } else if ( this.samplesProcessed > this.sustain && this.samplesProcessed <= this.release ) {
    amplitude = this.sustainLevel + (0 - this.sustainLevel) * ((this.samplesProcessed - this.sustain) / (this.release - this.sustain));
  }
 
  return amplitude;
};
     
ADSR.prototype.process = function(buffer) {
  for ( var i = 0; i < buffer.length; i++ ) {
    buffer[i] *= this.value();

    this.samplesProcessed++;
  }
 
  return buffer;
};
     
     
ADSR.prototype.isActive = function() {
  if ( this.samplesProcessed > this.release || this.samplesProcessed === -1 ) {
    return false;
  } else {
    return true;
  }
};

ADSR.prototype.disable = function() {
  this.samplesProcessed = -1;
};
 
function IIRFilter(type, cutoff, resonance, sampleRate) {
  this.sampleRate = sampleRate;

  switch(type) {
    case DSP.LOWPASS:
    case DSP.LP12:
      this.func = new IIRFilter.LP12(cutoff, resonance, sampleRate);
      break;
  }
}

IIRFilter.prototype.__defineGetter__('cutoff',
  function() {
    return this.func.cutoff;
  }
);

IIRFilter.prototype.__defineGetter__('resonance',
  function() {
    return this.func.resonance;
  }
);

IIRFilter.prototype.set = function(cutoff, resonance) {
  this.func.calcCoeff(cutoff, resonance);
};

IIRFilter.prototype.process = function(buffer) {
  this.func.process(buffer);
};

// Add an envelope to the filter
IIRFilter.prototype.addEnvelope = function(envelope) {
  if ( envelope instanceof ADSR ) {
    this.func.addEnvelope(envelope);
  } else {
    throw "Not an envelope.";
  }
};

IIRFilter.LP12 = function(cutoff, resonance, sampleRate) {
  this.sampleRate = sampleRate;
  this.vibraPos   = 0;
  this.vibraSpeed = 0;
  this.envelope = false;
 
  this.calcCoeff = function(cutoff, resonance) {
    this.w = 2.0 * Math.PI * cutoff / this.sampleRate;
    this.q = 1.0 - this.w / (2.0 * (resonance + 0.5 / (1.0 + this.w)) + this.w - 2.0);
    this.r = this.q * this.q;
    this.c = this.r + 1.0 - 2.0 * Math.cos(this.w) * this.q;
   
    this.cutoff = cutoff;
    this.resonance = resonance;
  };

  this.calcCoeff(cutoff, resonance);

  this.process = function(buffer) {
    for ( var i = 0; i < buffer.length; i++ ) {
      this.vibraSpeed += (buffer[i] - this.vibraPos) * this.c;
      this.vibraPos   += this.vibraSpeed;
      this.vibraSpeed *= this.r;
   
      /*
      var temp = this.vibraPos;
     
      if ( temp > 1.0 ) {
        temp = 1.0;
      } else if ( temp < -1.0 ) {
        temp = -1.0;
      } else if ( temp != temp ) {
        temp = 1;
      }
     
      buffer[i] = temp;
      */

      if (this.envelope) {
        buffer[i] = (buffer[i] * (1 - this.envelope.value())) + (this.vibraPos * this.envelope.value());
        this.envelope.samplesProcessed++;
      } else {
        buffer[i] = this.vibraPos;
      }
    }
  };
}; 

IIRFilter.LP12.prototype.addEnvelope = function(envelope) {
  this.envelope = envelope;
};

function IIRFilter2(type, cutoff, resonance, sampleRate) {
  this.type = type;
  this.cutoff = cutoff;
  this.resonance = resonance;
  this.sampleRate = sampleRate;

  this.f = Float32Array(4);
  this.f[0] = 0.0; // lp
  this.f[1] = 0.0; // hp
  this.f[2] = 0.0; // bp
  this.f[3] = 0.0; // br 
 
  this.calcCoeff = function(cutoff, resonance) {
    this.freq = 2 * Math.sin(Math.PI * Math.min(0.25, cutoff/(this.sampleRate*2)));  
    this.damp = Math.min(2 * (1 - Math.pow(resonance, 0.25)), Math.min(2, 2/this.freq - this.freq * 0.5));
  };

  this.calcCoeff(cutoff, resonance);
}

IIRFilter2.prototype.process = function(buffer) {
  var input, output;
  var f = this.f;

  for ( var i = 0; i < buffer.length; i++ ) {
    input = buffer[i];

    // first pass
    f[3] = input - this.damp * f[2];
    f[0] = f[0] + this.freq * f[2];
    f[1] = f[3] - f[0];
    f[2] = this.freq * f[1] + f[2];
    output = 0.5 * f[this.type];

    // second pass
    f[3] = input - this.damp * f[2];
    f[0] = f[0] + this.freq * f[2];
    f[1] = f[3] - f[0];
    f[2] = this.freq * f[1] + f[2];
    output += 0.5 * f[this.type];

    if (this.envelope) {
      buffer[i] = (buffer[i] * (1 - this.envelope.value())) + (output * this.envelope.value());
      this.envelope.samplesProcessed++;
    } else {
      buffer[i] = output;
    }
  }
};

IIRFilter2.prototype.addEnvelope = function(envelope) {
  if ( envelope instanceof ADSR ) {
    this.envelope = envelope;
  } else {
    throw "This is not an envelope.";
  }
};

IIRFilter2.prototype.set = function(cutoff, resonance) {
  this.calcCoeff(cutoff, resonance);
};



function WindowFunction(type, alpha) {
  this.alpha = alpha;
 
  switch(type) {
    case DSP.BARTLETT:
      this.func = WindowFunction.Bartlett;
      break;
     
    case DSP.BARTLETTHANN:
      this.func = WindowFunction.BartlettHann;
      break;
     
    case DSP.BLACKMAN:
      this.func = WindowFunction.Blackman;
      this.alpha = this.alpha || 0.16;
      break;
   
    case DSP.COSINE:
      this.func = WindowFunction.Cosine;
      break;
     
    case DSP.GAUSS:
      this.func = WindowFunction.Gauss;
      this.alpha = this.alpha || 0.25;
      break;
     
    case DSP.HAMMING:
      this.func = WindowFunction.Hamming;
      break;
     
    case DSP.HANN:
      this.func = WindowFunction.Hann;
      break;
   
    case DSP.LANCZOS:
      this.func = WindowFunction.Lanczoz;
      break;
     
    case DSP.RECTANGULAR:
      this.func = WindowFunction.Rectangular;
      break;
     
    case DSP.TRIANGULAR:
      this.func = WindowFunction.Triangular;
      break;
  }
}

WindowFunction.prototype.process = function(buffer) {
  var length = buffer.length;
  for ( var i = 0; i < length; i++ ) {
    buffer[i] *= this.func(length, i, this.alpha);
  }
  return buffer;
};

WindowFunction.Bartlett = function(length, index) {
  return 2 / (length - 1) * ((length - 1) / 2 - Math.abs(index - (length - 1) / 2));
};

WindowFunction.BartlettHann = function(length, index) {
  return 0.62 - 0.48 * Math.abs(index / (length - 1) - 0.5) - 0.38 * Math.cos(DSP.TWO_PI * index / (length - 1));
};

WindowFunction.Blackman = function(length, index, alpha) {
  var a0 = (1 - alpha) / 2;
  var a1 = 0.5;
  var a2 = alpha / 2;

  return a0 - a1 * Math.cos(DSP.TWO_PI * index / (length - 1)) + a2 * Math.cos(4 * Math.PI * index / (length - 1));
};

WindowFunction.Cosine = function(length, index) {
  return Math.cos(Math.PI * index / (length - 1) - Math.PI / 2);
};

WindowFunction.Gauss = function(length, index, alpha) {
  return Math.pow(Math.E, -0.5 * Math.pow((index - (length - 1) / 2) / (alpha * (length - 1) / 2), 2));
};

WindowFunction.Hamming = function(length, index) {
  return 0.54 - 0.46 * Math.cos(DSP.TWO_PI * index / (length - 1));
};

WindowFunction.Hann = function(length, index) {
  return 0.5 * (1 - Math.cos(DSP.TWO_PI * index / (length - 1)));
};

WindowFunction.Lanczos = function(length, index) {
  var x = 2 * index / (length - 1) - 1;
  return Math.sin(Math.PI * x) / (Math.PI * x);
};

WindowFunction.Rectangular = function(length, index) {
  return 1;
};

WindowFunction.Triangular = function(length, index) {
  return 2 / length * (length / 2 - Math.abs(index - (length - 1) / 2));
};

function sinh (arg) {
  // Returns the hyperbolic sine of the number, defined as (exp(number) - exp(-number))/2 
  //
  // version: 1004.2314
  // discuss at: http://phpjs.org/functions/sinh    // +   original by: Onno Marsman
  // *     example 1: sinh(-0.9834330348825909);
  // *     returns 1: -1.1497971402636502
  return (Math.exp(arg) - Math.exp(-arg))/2;
}

/* 
 *  Biquad filter
 * 
 *  Created by Ricard Marxer <email@ricardmarxer.com> on 2010-05-23.
 *  Copyright 2010 Ricard Marxer. All rights reserved.
 *
 */
// Implementation based on:
// http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt
function Biquad(type, sampleRate) {
  this.Fs = sampleRate;
  this.type = type;  // type of the filter
  this.parameterType = DSP.Q; // type of the parameter

  this.x_1_l = 0;
  this.x_2_l = 0;
  this.y_1_l = 0;
  this.y_2_l = 0;

  this.x_1_r = 0;
  this.x_2_r = 0;
  this.y_1_r = 0;
  this.y_2_r = 0;

  this.b0 = 1;
  this.a0 = 1;

  this.b1 = 0;
  this.a1 = 0;

  this.b2 = 0;
  this.a2 = 0;

  this.b0a0 = this.b0 / this.a0;
  this.b1a0 = this.b1 / this.a0;
  this.b2a0 = this.b2 / this.a0;
  this.a1a0 = this.a1 / this.a0;
  this.a2a0 = this.a2 / this.a0;

  this.f0 = 3000;   // "wherever it's happenin', man."  Center Frequency or
                    // Corner Frequency, or shelf midpoint frequency, depending
                    // on which filter type.  The "significant frequency".

  this.dBgain = 12; // used only for peaking and shelving filters

  this.Q = 1;       // the EE kind of definition, except for peakingEQ in which A*Q is
                    // the classic EE Q.  That adjustment in definition was made so that
                    // a boost of N dB followed by a cut of N dB for identical Q and
                    // f0/Fs results in a precisely flat unity gain filter or "wire".

  this.BW = -3;     // the bandwidth in octaves (between -3 dB frequencies for BPF
                    // and notch or between midpoint (dBgain/2) gain frequencies for
                    // peaking EQ

  this.S = 1;       // a "shelf slope" parameter (for shelving EQ only).  When S = 1,
                    // the shelf slope is as steep as it can be and remain monotonically
                    // increasing or decreasing gain with frequency.  The shelf slope, in
                    // dB/octave, remains proportional to S for all other values for a
                    // fixed f0/Fs and dBgain.

  this.coefficients = function() {
    var b = [this.b0, this.b1, this.b2];
    var a = [this.a0, this.a1, this.a2];
    return {b: b, a:a};
  };

  this.setFilterType = function(type) {
    this.type = type;
    this.recalculateCoefficients();
  };

  this.setSampleRate = function(rate) {
    this.Fs = rate;
    this.recalculateCoefficients();
  };

  this.setQ = function(q) {
    this.parameterType = DSP.Q;
    this.Q = Math.max(Math.min(q, 115.0), 0.001);
    this.recalculateCoefficients();
  };

  this.setBW = function(bw) {
    this.parameterType = DSP.BW;
    this.BW = bw;
    this.recalculateCoefficients();
  };

  this.setS = function(s) {
    this.parameterType = DSP.S;
    this.S = Math.max(Math.min(s, 5.0), 0.0001);
    this.recalculateCoefficients();
  };

  this.setF0 = function(freq) {
    this.f0 = freq;
    this.recalculateCoefficients();
  }; 
 
  this.setDbGain = function(g) {
    this.dBgain = g;
    this.recalculateCoefficients();
  };

  this.recalculateCoefficients = function() {
    var A;
    if (type === DSP.PEAKING_EQ || type === DSP.LOW_SHELF || type === DSP.HIGH_SHELF ) {
      A = Math.pow(10, (this.dBgain/40));  // for peaking and shelving EQ filters only
    } else {
      A  = Math.sqrt( Math.pow(10, (this.dBgain/20)) );   
    }

    var w0 = DSP.TWO_PI * this.f0 / this.Fs;

    var cosw0 = Math.cos(w0);
    var sinw0 = Math.sin(w0);

    var alpha = 0;
   
    switch (this.parameterType) {
      case DSP.Q:
        alpha = sinw0/(2*this.Q);
        break;
           
      case DSP.BW:
        alpha = sinw0 * sinh( Math.LN2/2 * this.BW * w0/sinw0 );
        break;

      case DSP.S:
        alpha = sinw0/2 * Math.sqrt( (A + 1/A)*(1/this.S - 1) + 2 );
        break;
    }

    /**
        FYI: The relationship between bandwidth and Q is
             1/Q = 2*sinh(ln(2)/2*BW*w0/sin(w0))     (digital filter w BLT)
        or   1/Q = 2*sinh(ln(2)/2*BW)             (analog filter prototype)

        The relationship between shelf slope and Q is
             1/Q = sqrt((A + 1/A)*(1/S - 1) + 2)
    */

    var coeff;

    switch (this.type) {
      case DSP.LPF:       // H(s) = 1 / (s^2 + s/Q + 1)
        this.b0 =  (1 - cosw0)/2;
        this.b1 =   1 - cosw0;
        this.b2 =  (1 - cosw0)/2;
        this.a0 =   1 + alpha;
        this.a1 =  -2 * cosw0;
        this.a2 =   1 - alpha;
        break;

      case DSP.HPF:       // H(s) = s^2 / (s^2 + s/Q + 1)
        this.b0 =  (1 + cosw0)/2;
        this.b1 = -(1 + cosw0);
        this.b2 =  (1 + cosw0)/2;
        this.a0 =   1 + alpha;
        this.a1 =  -2 * cosw0;
        this.a2 =   1 - alpha;
        break;

      case DSP.BPF_CONSTANT_SKIRT:       // H(s) = s / (s^2 + s/Q + 1)  (constant skirt gain, peak gain = Q)
        this.b0 =   sinw0/2;
        this.b1 =   0;
        this.b2 =  -sinw0/2;
        this.a0 =   1 + alpha;
        this.a1 =  -2*cosw0;
        this.a2 =   1 - alpha;
        break;

      case DSP.BPF_CONSTANT_PEAK:       // H(s) = (s/Q) / (s^2 + s/Q + 1)      (constant 0 dB peak gain)
        this.b0 =   alpha;
        this.b1 =   0;
        this.b2 =  -alpha;
        this.a0 =   1 + alpha;
        this.a1 =  -2*cosw0;
        this.a2 =   1 - alpha;
        break;

      case DSP.NOTCH:     // H(s) = (s^2 + 1) / (s^2 + s/Q + 1)
        this.b0 =   1;
        this.b1 =  -2*cosw0;
        this.b2 =   1;
        this.a0 =   1 + alpha;
        this.a1 =  -2*cosw0;
        this.a2 =   1 - alpha;
        break;

      case DSP.APF:       // H(s) = (s^2 - s/Q + 1) / (s^2 + s/Q + 1)
        this.b0 =   1 - alpha;
        this.b1 =  -2*cosw0;
        this.b2 =   1 + alpha;
        this.a0 =   1 + alpha;
        this.a1 =  -2*cosw0;
        this.a2 =   1 - alpha;
        break;

      case DSP.PEAKING_EQ:  // H(s) = (s^2 + s*(A/Q) + 1) / (s^2 + s/(A*Q) + 1)
        this.b0 =   1 + alpha*A;
        this.b1 =  -2*cosw0;
        this.b2 =   1 - alpha*A;
        this.a0 =   1 + alpha/A;
        this.a1 =  -2*cosw0;
        this.a2 =   1 - alpha/A;
        break;

      case DSP.LOW_SHELF:   // H(s) = A * (s^2 + (sqrt(A)/Q)*s + A)/(A*s^2 + (sqrt(A)/Q)*s + 1)
        coeff = sinw0 * Math.sqrt( (A^2 + 1)*(1/this.S - 1) + 2*A );
        this.b0 =    A*((A+1) - (A-1)*cosw0 + coeff);
        this.b1 =  2*A*((A-1) - (A+1)*cosw0);
        this.b2 =    A*((A+1) - (A-1)*cosw0 - coeff);
        this.a0 =       (A+1) + (A-1)*cosw0 + coeff;
        this.a1 =   -2*((A-1) + (A+1)*cosw0);
        this.a2 =       (A+1) + (A-1)*cosw0 - coeff;
        break;

      case DSP.HIGH_SHELF:   // H(s) = A * (A*s^2 + (sqrt(A)/Q)*s + 1)/(s^2 + (sqrt(A)/Q)*s + A)
        coeff = sinw0 * Math.sqrt( (A^2 + 1)*(1/this.S - 1) + 2*A );
        this.b0 =    A*((A+1) + (A-1)*cosw0 + coeff);
        this.b1 = -2*A*((A-1) + (A+1)*cosw0);
        this.b2 =    A*((A+1) + (A-1)*cosw0 - coeff);
        this.a0 =       (A+1) - (A-1)*cosw0 + coeff;
        this.a1 =    2*((A-1) - (A+1)*cosw0);
        this.a2 =       (A+1) - (A-1)*cosw0 - coeff;
        break;
    }
   
    this.b0a0 = this.b0/this.a0;
    this.b1a0 = this.b1/this.a0;
    this.b2a0 = this.b2/this.a0;
    this.a1a0 = this.a1/this.a0;
    this.a2a0 = this.a2/this.a0;
  };

  this.process = function(buffer) {
      //y[n] = (b0/a0)*x[n] + (b1/a0)*x[n-1] + (b2/a0)*x[n-2]
      //       - (a1/a0)*y[n-1] - (a2/a0)*y[n-2]

      var len = buffer.length;
      var output = new Float32Array(len);

      for ( var i=0; i<buffer.length; i++ ) {
        output[i] = this.b0a0*buffer[i] + this.b1a0*this.x_1_l + this.b2a0*this.x_2_l - this.a1a0*this.y_1_l - this.a2a0*this.y_2_l;
        this.y_2_l = this.y_1_l;
        this.y_1_l = output[i];
        this.x_2_l = this.x_1_l;
        this.x_1_l = buffer[i];
      }

      return output;
  };

  this.processStereo = function(buffer) {
      //y[n] = (b0/a0)*x[n] + (b1/a0)*x[n-1] + (b2/a0)*x[n-2]
      //       - (a1/a0)*y[n-1] - (a2/a0)*y[n-2]

      var len = buffer.length;
      var output = new Float32Array(len);
     
      for (var i = 0; i < len/2; i++) {
        output[2*i] = this.b0a0*buffer[2*i] + this.b1a0*this.x_1_l + this.b2a0*this.x_2_l - this.a1a0*this.y_1_l - this.a2a0*this.y_2_l;
        this.y_2_l = this.y_1_l;
        this.y_1_l = output[2*i];
        this.x_2_l = this.x_1_l;
        this.x_1_l = buffer[2*i];

        output[2*i+1] = this.b0a0*buffer[2*i+1] + this.b1a0*this.x_1_r + this.b2a0*this.x_2_r - this.a1a0*this.y_1_r - this.a2a0*this.y_2_r;
        this.y_2_r = this.y_1_r;
        this.y_1_r = output[2*i+1];
        this.x_2_r = this.x_1_r;
        this.x_1_r = buffer[2*i+1];
      }

      return output;
  };
}

/* 
 *  Magnitude to decibels
 * 
 *  Created by Ricard Marxer <email@ricardmarxer.com> on 2010-05-23.
 *  Copyright 2010 Ricard Marxer. All rights reserved.
 *
 *  @buffer array of magnitudes to convert to decibels
 *
 *  @returns the array in decibels
 *
 */
DSP.mag2db = function(buffer) {
  var minDb = -120;
  var minMag = Math.pow(10.0, minDb / 20.0);

  var log = Math.log;
  var max = Math.max;
 
  var result = Float32Array(buffer.length);
  for (var i=0; i<buffer.length; i++) {
    result[i] = 20.0*log(max(buffer[i], minMag));
  }

  return result;
};

/* 
 *  Frequency response
 * 
 *  Created by Ricard Marxer <email@ricardmarxer.com> on 2010-05-23.
 *  Copyright 2010 Ricard Marxer. All rights reserved.
 *
 *  Calculates the frequency response at the given points.
 *
 *  @b b coefficients of the filter
 *  @a a coefficients of the filter
 *  @w w points (normally between -PI and PI) where to calculate the frequency response
 *
 *  @returns the frequency response in magnitude
 *
 */
DSP.freqz = function(b, a, w) {
  var i, j;

  if (!w) {
    w = Float32Array(200);
    for (i=0;i<w.length; i++) {
      w[i] = DSP.TWO_PI/w.length * i - Math.PI;
    }
  }

  var result = Float32Array(w.length);
 
  var sqrt = Math.sqrt;
  var cos = Math.cos;
  var sin = Math.sin;
 
  for (i=0; i<w.length; i++) {
    var numerator = {real:0.0, imag:0.0};
    for (j=0; j<b.length; j++) {
      numerator.real += b[j] * cos(-j*w[i]);
      numerator.imag += b[j] * sin(-j*w[i]);
    }

    var denominator = {real:0.0, imag:0.0};
    for (j=0; j<a.length; j++) {
      denominator.real += a[j] * cos(-j*w[i]);
      denominator.imag += a[j] * sin(-j*w[i]);
    }
 
    result[i] =  sqrt(numerator.real*numerator.real + numerator.imag*numerator.imag) / sqrt(denominator.real*denominator.real + denominator.imag*denominator.imag);
  }

  return result;
};

/* 
 *  Graphical Equalizer
 *
 *  Implementation of a graphic equalizer with a configurable bands-per-octave
 *  and minimum and maximum frequencies
 * 
 *  Created by Ricard Marxer <email@ricardmarxer.com> on 2010-05-23.
 *  Copyright 2010 Ricard Marxer. All rights reserved.
 *
 */
function GraphicalEq(sampleRate) {
  this.FS = sampleRate;
  this.minFreq = 40.0;
  this.maxFreq = 16000.0;

  this.bandsPerOctave = 1.0;

  this.filters = [];
  this.freqzs = [];

  this.calculateFreqzs = true;

  this.recalculateFilters = function() {
    var bandCount = Math.round(Math.log(this.maxFreq/this.minFreq) * this.bandsPerOctave/ Math.LN2);

    this.filters = [];
    for (var i=0; i<bandCount; i++) {
      var freq = this.minFreq*(Math.pow(2, i/this.bandsPerOctave));
      var newFilter = new Biquad(DSP.PEAKING_EQ, this.FS);
      newFilter.setDbGain(0);
      newFilter.setBW(1/this.bandsPerOctave);
      newFilter.setF0(freq);
      this.filters[i] = newFilter;
      this.recalculateFreqz(i);
    }
  };

  this.setMinimumFrequency = function(freq) {
    this.minFreq = freq;
    this.recalculateFilters();
  };

  this.setMaximumFrequency = function(freq) {
    this.maxFreq = freq;
    this.recalculateFilters();
  };

  this.setBandsPerOctave = function(bands) {
    this.bandsPerOctave = bands;
    this.recalculateFilters();
  };

  this.setBandGain = function(bandIndex, gain) {
    if (bandIndex < 0 || bandIndex > (this.filters.length-1)) {
      throw "The band index of the graphical equalizer is out of bounds.";
    }

    if (!gain) {
      throw "A gain must be passed.";
    }
   
    this.filters[bandIndex].setDbGain(gain);
    this.recalculateFreqz(bandIndex);
  };
 
  this.recalculateFreqz = function(bandIndex) {
    if (!this.calculateFreqzs) {
      return;
    }

    if (bandIndex < 0 || bandIndex > (this.filters.length-1)) {
      throw "The band index of the graphical equalizer is out of bounds. " + bandIndex + " is out of [" + 0 + ", " + this.filters.length-1 + "]";
    }
       
    if (!this.w) {
      this.w = Float32Array(400);
      for (var i=0; i<this.w.length; i++) {
         this.w[i] = Math.PI/this.w.length * i;
      }
    }
   
    var b = [this.filters[bandIndex].b0, this.filters[bandIndex].b1, this.filters[bandIndex].b2];
    var a = [this.filters[bandIndex].a0, this.filters[bandIndex].a1, this.filters[bandIndex].a2];

    this.freqzs[bandIndex] = DSP.mag2db(DSP.freqz(b, a, this.w));
  };

  this.process = function(buffer) {
    var output = buffer;

    for (var i = 0; i < this.filters.length; i++) {
      output = this.filters[i].process(output);
    }

    return output;
  };

  this.processStereo = function(buffer) {
    var output = buffer;

    for (var i = 0; i < this.filters.length; i++) {
      output = this.filters[i].processStereo(output);
    }

    return output;
  };
}

/**
 * MultiDelay effect by Almer Thie (http://code.almeros.com).
 * Copyright 2010 Almer Thie. All rights reserved.
 * Example: http://code.almeros.com/code-examples/delay-firefox-audio-api/
 *
 * This is a delay that feeds it's own delayed signal back into its circular
 * buffer. Also known as a CombFilter.
 *
 * Compatible with interleaved stereo (or more channel) buffers and
 * non-interleaved mono buffers.
 *
 * @param {Number} maxDelayInSamplesSize Maximum possible delay in samples (size of circular buffer)
 * @param {Number} delayInSamples Initial delay in samples
 * @param {Number} masterVolume Initial master volume. Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify)
 * @param {Number} delayVolume Initial feedback delay volume. Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify)
 *
 * @constructor
 */
function MultiDelay(maxDelayInSamplesSize, delayInSamples, masterVolume, delayVolume) {
  this.delayBufferSamples   = new Float32Array(maxDelayInSamplesSize); // The maximum size of delay
  this.delayInputPointer     = delayInSamples;
  this.delayOutputPointer   = 0;
 
  this.delayInSamples   = delayInSamples;
  this.masterVolume     = masterVolume;
  this.delayVolume     = delayVolume;
}

/**
 * Change the delay time in samples.
 *
 * @param {Number} delayInSamples Delay in samples
 */
MultiDelay.prototype.setDelayInSamples = function (delayInSamples) {
  this.delayInSamples = delayInSamples;
 
  this.delayInputPointer = this.delayOutputPointer + delayInSamples;

  if (this.delayInputPointer >= this.delayBufferSamples.length-1) {
    this.delayInputPointer = this.delayInputPointer - this.delayBufferSamples.length; 
  }
};

/**
 * Change the master volume.
 *
 * @param {Number} masterVolume Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify)
 */
MultiDelay.prototype.setMasterVolume = function(masterVolume) {
  this.masterVolume = masterVolume;
};

/**
 * Change the delay feedback volume.
 *
 * @param {Number} delayVolume Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify)
 */
MultiDelay.prototype.setDelayVolume = function(delayVolume) {
  this.delayVolume = delayVolume;
};

/**
 * Process a given interleaved or mono non-interleaved float value Array and adds the delayed audio.
 *
 * @param {Array} samples Array containing Float values or a Float32Array
 *
 * @returns A new Float32Array interleaved or mono non-interleaved as was fed to this function.
 */
MultiDelay.prototype.process = function(samples) {
  // NB. Make a copy to put in the output samples to return.
  var outputSamples = new Float32Array(samples.length);

  for (var i=0; i<samples.length; i++) {
    // delayBufferSamples could contain initial NULL's, return silence in that case
    var delaySample = (this.delayBufferSamples[this.delayOutputPointer] === null ? 0.0 : this.delayBufferSamples[this.delayOutputPointer]);
   
    // Mix normal audio data with delayed audio
    var sample = (delaySample * this.delayVolume) + samples[i];
   
    // Add audio data with the delay in the delay buffer
    this.delayBufferSamples[this.delayInputPointer] = sample;
   
    // Return the audio with delay mix
    outputSamples[i] = sample * this.masterVolume;
   
    // Manage circulair delay buffer pointers
    this.delayInputPointer++;
    if (this.delayInputPointer >= this.delayBufferSamples.length-1) {
      this.delayInputPointer = 0;
    }
     
    this.delayOutputPointer++;
    if (this.delayOutputPointer >= this.delayBufferSamples.length-1) {
      this.delayOutputPointer = 0; 
    } 
  }
 
  return outputSamples;
};

/**
 * SingleDelay effect by Almer Thie (http://code.almeros.com).
 * Copyright 2010 Almer Thie. All rights reserved.
 * Example: See usage in Reverb class
 *
 * This is a delay that does NOT feeds it's own delayed signal back into its 
 * circular buffer, neither does it return the original signal. Also known as
 * an AllPassFilter(?).
 *
 * Compatible with interleaved stereo (or more channel) buffers and
 * non-interleaved mono buffers.
 *
 * @param {Number} maxDelayInSamplesSize Maximum possible delay in samples (size of circular buffer)
 * @param {Number} delayInSamples Initial delay in samples
 * @param {Number} delayVolume Initial feedback delay volume. Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify)
 *
 * @constructor
 */

function SingleDelay(maxDelayInSamplesSize, delayInSamples, delayVolume) {
  this.delayBufferSamples = new Float32Array(maxDelayInSamplesSize); // The maximum size of delay
  this.delayInputPointer  = delayInSamples;
  this.delayOutputPointer = 0;
 
  this.delayInSamples     = delayInSamples;
  this.delayVolume        = delayVolume;
}

/**
 * Change the delay time in samples.
 *
 * @param {Number} delayInSamples Delay in samples
 */
SingleDelay.prototype.setDelayInSamples = function(delayInSamples) {
  this.delayInSamples = delayInSamples;
  this.delayInputPointer = this.delayOutputPointer + delayInSamples;

  if (this.delayInputPointer >= this.delayBufferSamples.length-1) {
    this.delayInputPointer = this.delayInputPointer - this.delayBufferSamples.length; 
  }
};

/**
 * Change the return signal volume.
 *
 * @param {Number} delayVolume Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify)
 */
SingleDelay.prototype.setDelayVolume = function(delayVolume) {
  this.delayVolume = delayVolume;
};

/**
 * Process a given interleaved or mono non-interleaved float value Array and
 * returns the delayed audio.
 *
 * @param {Array} samples Array containing Float values or a Float32Array
 *
 * @returns A new Float32Array interleaved or mono non-interleaved as was fed to this function.
 */
SingleDelay.prototype.process = function(samples) {
  // NB. Make a copy to put in the output samples to return.
  var outputSamples = new Float32Array(samples.length);

  for (var i=0; i<samples.length; i++) {

    // Add audio data with the delay in the delay buffer
    this.delayBufferSamples[this.delayInputPointer] = samples[i];
   
    // delayBufferSamples could contain initial NULL's, return silence in that case
    var delaySample = this.delayBufferSamples[this.delayOutputPointer];

    // Return the audio with delay mix
    outputSamples[i] = delaySample * this.delayVolume;

    // Manage circulair delay buffer pointers
    this.delayInputPointer++;

    if (this.delayInputPointer >= this.delayBufferSamples.length-1) {
      this.delayInputPointer = 0;
    }
     
    this.delayOutputPointer++;

    if (this.delayOutputPointer >= this.delayBufferSamples.length-1) {
      this.delayOutputPointer = 0; 
    } 
  }
 
  return outputSamples;
};

/**
 * Reverb effect by Almer Thie (http://code.almeros.com).
 * Copyright 2010 Almer Thie. All rights reserved.
 * Example: http://code.almeros.com/code-examples/reverb-firefox-audio-api/
 *
 * This reverb consists of 6 SingleDelays, 6 MultiDelays and an IIRFilter2
 * for each of the two stereo channels.
 *
 * Compatible with interleaved stereo buffers only!
 *
 * @param {Number} maxDelayInSamplesSize Maximum possible delay in samples (size of circular buffers)
 * @param {Number} delayInSamples Initial delay in samples for internal (Single/Multi)delays
 * @param {Number} masterVolume Initial master volume. Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify)
 * @param {Number} mixVolume Initial reverb signal mix volume. Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify)
 * @param {Number} delayVolume Initial feedback delay volume for internal (Single/Multi)delays. Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify)
 * @param {Number} dampFrequency Initial low pass filter frequency. 0 to 44100 (depending on your maximum sampling frequency)
 *
 * @constructor
 */
function Reverb(maxDelayInSamplesSize, delayInSamples, masterVolume, mixVolume, delayVolume, dampFrequency) {
  this.delayInSamples   = delayInSamples;
  this.masterVolume     = masterVolume;
  this.mixVolume       = mixVolume;
  this.delayVolume     = delayVolume;
  this.dampFrequency     = dampFrequency;
 
  this.NR_OF_MULTIDELAYS = 6;
  this.NR_OF_SINGLEDELAYS = 6;
 
  this.LOWPASSL = new IIRFilter2(DSP.LOWPASS, dampFrequency, 0, 44100);
  this.LOWPASSR = new IIRFilter2(DSP.LOWPASS, dampFrequency, 0, 44100);
 
  this.singleDelays = [];
  
  var i, delayMultiply;

  for (i = 0; i < this.NR_OF_SINGLEDELAYS; i++) {
    delayMultiply = 1.0 + (i/7.0); // 1.0, 1.1, 1.2...
    this.singleDelays[i] = new SingleDelay(maxDelayInSamplesSize, Math.round(this.delayInSamples * delayMultiply), this.delayVolume);
  }
 
  this.multiDelays = [];

  for (i = 0; i < this.NR_OF_MULTIDELAYS; i++) {
    delayMultiply = 1.0 + (i/10.0); // 1.0, 1.1, 1.2... 
    this.multiDelays[i] = new MultiDelay(maxDelayInSamplesSize, Math.round(this.delayInSamples * delayMultiply), this.masterVolume, this.delayVolume);
  }
}

/**
 * Change the delay time in samples as a base for all delays.
 *
 * @param {Number} delayInSamples Delay in samples
 */
Reverb.prototype.setDelayInSamples = function (delayInSamples){
  this.delayInSamples = delayInSamples;

  var i, delayMultiply;
 
  for (i = 0; i < this.NR_OF_SINGLEDELAYS; i++) {
    delayMultiply = 1.0 + (i/7.0); // 1.0, 1.1, 1.2...
    this.singleDelays[i].setDelayInSamples( Math.round(this.delayInSamples * delayMultiply) );
  }
   
  for (i = 0; i < this.NR_OF_MULTIDELAYS; i++) {
    delayMultiply = 1.0 + (i/10.0); // 1.0, 1.1, 1.2...
    this.multiDelays[i].setDelayInSamples( Math.round(this.delayInSamples * delayMultiply) );
  }
};

/**
 * Change the master volume.
 *
 * @param {Number} masterVolume Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify)
 */
Reverb.prototype.setMasterVolume = function (masterVolume){
  this.masterVolume = masterVolume;
};

/**
 * Change the reverb signal mix level.
 *
 * @param {Number} mixVolume Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify)
 */
Reverb.prototype.setMixVolume = function (mixVolume){
  this.mixVolume = mixVolume;
};

/**
 * Change all delays feedback volume.
 *
 * @param {Number} delayVolume Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify)
 */
Reverb.prototype.setDelayVolume = function (delayVolume){
  this.delayVolume = delayVolume;
 
  var i;

  for (i = 0; i<this.NR_OF_SINGLEDELAYS; i++) {
    this.singleDelays[i].setDelayVolume(this.delayVolume);
  } 
 
  for (i = 0; i<this.NR_OF_MULTIDELAYS; i++) {
    this.multiDelays[i].setDelayVolume(this.delayVolume);
  } 
};

/**
 * Change the Low Pass filter frequency.
 *
 * @param {Number} dampFrequency low pass filter frequency. 0 to 44100 (depending on your maximum sampling frequency)
 */
Reverb.prototype.setDampFrequency = function (dampFrequency){
  this.dampFrequency = dampFrequency;
 
  this.LOWPASSL.set(dampFrequency, 0);
  this.LOWPASSR.set(dampFrequency, 0); 
};

/**
 * Process a given interleaved float value Array and copies and adds the reverb signal.
 *
 * @param {Array} samples Array containing Float values or a Float32Array
 *
 * @returns A new Float32Array interleaved buffer.
 */
Reverb.prototype.process = function (interleavedSamples){ 
  // NB. Make a copy to put in the output samples to return.
  var outputSamples = new Float32Array(interleavedSamples.length);
 
  // Perform low pass on the input samples to mimick damp
  var leftRightMix = DSP.deinterleave(interleavedSamples);
  this.LOWPASSL.process( leftRightMix[DSP.LEFT] );
  this.LOWPASSR.process( leftRightMix[DSP.RIGHT] ); 
  var filteredSamples = DSP.interleave(leftRightMix[DSP.LEFT], leftRightMix[DSP.RIGHT]);

  var i;

  // Process MultiDelays in parallel
  for (i = 0; i<this.NR_OF_MULTIDELAYS; i++) {
    // Invert the signal of every even multiDelay
    outputSamples = DSP.mixSampleBuffers(outputSamples, this.multiDelays[i].process(filteredSamples), 2%i === 0, this.NR_OF_MULTIDELAYS);
  }
 
  // Process SingleDelays in series
  var singleDelaySamples = new Float32Array(outputSamples.length);
  for (i = 0; i<this.NR_OF_SINGLEDELAYS; i++) {
    // Invert the signal of every even singleDelay
    singleDelaySamples = DSP.mixSampleBuffers(singleDelaySamples, this.singleDelays[i].process(outputSamples), 2%i === 0, 1);
  }

  // Apply the volume of the reverb signal
  for (i = 0; i<singleDelaySamples.length; i++) {
    singleDelaySamples[i] *= this.mixVolume;
  }
 
  // Mix the original signal with the reverb signal
  outputSamples = DSP.mixSampleBuffers(singleDelaySamples, interleavedSamples, 0, 1);

  // Apply the master volume to the complete signal
  for (i = 0; i<outputSamples.length; i++) {
    outputSamples[i] *= this.masterVolume;
  }
   
  return outputSamples;
};

/dev/2dshooting2/devver/20170416/test.html


<!doctype html>
<html lang="ja">
<head>
    <meta charset="UTF-8">
    <title>3d sample</title>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/three.js/84/three.min.js"></script>
    <script>
// 共通で使用する変数
var mesh, renderer, scene, camera;

// 設定
var width = 1280,
    height = 640;


document.addEventListener( 'DOMContentLoaded', function(){

    // シーンの用意
    scene = new THREE.Scene();

    // カメラの設定
    var fov = 45, // 画角
        aspect = width / height, // アスペクト比
        near = 1, // 手前
        far = 700; // 奥行き
    camera = new THREE.PerspectiveCamera( fov, aspect, near, far ); // カメラの準備
    camera.position.set( 0, 0, 50 ); // カメラ位置の設定

    // レンダラーの設定
    renderer = new THREE.WebGLRenderer(); // レンダラーの用意
    renderer.setSize( width, height ); // サイズを指定
    var bgColor = 0x000000;
    renderer.setClearColor(bgColor, 1); // 背景色を指定
    document.body.appendChild( renderer.domElement ); // bodyへ追加

    // ライトの設定
    var lightColor = 0xffffff; // ライトの色
    var directionalLight = new THREE.DirectionalLight( lightColor ); // ライトの色を指定
    directionalLight.position.set( 1, 1, 1 ); // ライトの位置の設定
    scene.add( directionalLight ); // ライトの追加

    var ambient = new THREE.AmbientLight(0xffffff);
    scene.add(ambient);

    // jsonファイルの読み込み
    var loader = new THREE.JSONLoader();
    var json = './data/test.json';// jsonパスの指定
    loader.load( json, function ( geometry, materials ) {
        var faceMaterial = new THREE.MeshFaceMaterial( materials );
        var materialColor = 0xff8700; // マテリアルの色
        faceMaterial.materials[0].color = new THREE.Color(materialColor); // マテリアルの色の設定
        //faceMaterial.materials[0].wireframe = true; // ワイヤーフレーム表示にする

        mesh = new THREE.Mesh( geometry, faceMaterial );
        mesh.position.set( 0,0,0); // 位置の設定
        mesh.scale.set( 10, 10, 10 ); // スケールの設定

        scene.add( mesh ); // シーンへメッシュの追加

        renderLoop(); // レンダリング実行
    } );

});

// レンダリング処理
function renderLoop () {
    var speed = 0.005; // 追加される値
    // メッシュの回転
    var meshRotaX = mesh.rotation.x + speed,
        meshRotaY = mesh.rotation.y + speed,
        meshRotaZ = mesh.rotation.z + speed;
    mesh.rotation.set(meshRotaX, meshRotaY, meshRotaZ);
    renderer.render( scene, camera ); // レンダリング
    requestAnimationFrame( renderLoop ); // ループ処理
}      
    </script>
</head>
<body>
</body>
</html>