Add initial distortion test

src/distortion.js

@@ -0,0 +1,100 @@
+define(function (require) {
+  'use strict';
+
+  var p5sound = require('master');
+
+
+  function makeDistortionCurve(amount) {
+    var k = typeof amount === 'number' ? amount : 50,
+      n_samples = 44100,
+      curve = new Float32Array(n_samples),
+      deg = Math.PI / 180,
+      i = 0,
+      x;
+    for ( ; i < n_samples; ++i ) {
+      x = i * 2 / n_samples - 1;
+      curve[i] = ( 3 + k ) * x * 20 * deg / ( Math.PI + k * Math.abs(x) );
+    }
+    return curve;
+  };
+
+  /**
+   * A waveshaper Distortion effect
+   *
+   * @class p5.Distortion
+   * @constructor
+   * @param {String} [waveShape='sine'] 'sine', 'triangle', 'sawtooth', or 'square'.
+   * @param {String} [oversample='none'] 'none', '2x', or '4x'.
+   *
+   * @return {Object}   Distortion object
+   */
+  p5.Distortion = function(waveShape, oversample) {
+    this.ac = p5sound.audiocontext;
+
+    this.input = this.ac.createGain();
+    this.output = this.ac.createGain();
+
+    /**
+     *  The p5.Filter is built with a
+     *  <a href="http://www.w3.org/TR/webaudio/#WaveShaperNode">
+     *  Web Audio WaveShaper Node</a>.
+     *
+     *  @property WaveShaperNode
+     *  @type {Object}  AudioNode
+     */
+     this.waveShaper = this.ac.createWaveShaper();
+
+     // TODO: Make some waveshape presets
+     this.waveShaper.curve = makeDistortionCurve(400);
+     this.waveShaper.oversample = oversample;
+
+     this.input.connect(this.waveShaper);
+     this.waveShaper.connect(this.output);
+
+     this.connect();
+
+     if (waveShape) {
+       this.setType(waveShape);
+     }
+     if (oversample) {
+       this.setOversample(oversample);
+     }
+
+     // add to the soundArray
+     p5sound.soundArray.push(this);
+  }
+
+  /**
+   * Set the waveform type of the waveshaper. Types include:
+   * 'sine' (default), 'triangle', 'sawtooh', 'square'.
+   *
+   * @method setType
+   * @param {String}
+   */
+  /*
+  p5.prototype.setType = function(waveShape) {
+
+    this.curve =
+  }
+  */
+
+  /**
+   *  Send output to a p5.sound or web audio object
+   *
+   *  @method connect
+   *  @param  {Object} unit
+   */
+  p5.Distortion.prototype.connect = function(unit) {
+    var u = unit || p5.soundOut.input;
+    this.output.connect(u);
+  };
+
+  /**
+   *  Disconnect all output.
+   *
+   *  @method disconnect
+   */
+  p5.Distortion.prototype.disconnect = function() {
+    this.output.disconnect();
+  };
+});