typed arrays.js

/**
  @hint
  @see https://wiki.mozilla.org/Audio_Data_API
  @see http://www.opensource.apple.com/source/WebCore/WebCore-737.5/html/canvas/
  @see https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/doc/spec/TypedArray-spec.html  

  Array.U32 = $G.Uint32Array || $G.WebGLUnsignedIntArray || $G.CanvasUnsignedIntArray || Array;
  Array.U16 = $G.Uint16Array || $G.WebGLUnsignedShortArray || $G.CanvasUnsignedShortArray || Array;
  Array.U8 = $G.Uint8Array || $G.WebGLUnsignedByteArray || $G.CanvasUnsignedByteArray || Array;

  Array.S32 = $G.Int32Array || $G.WebGLIntArray || $G.CanvasIntArray || Array;
  Array.S16 = $G.Int16Array || $G.WebGLShortArray || $G.CanvasShortArray || Array;
  Array.S8 = $G.Int8Array || $G.WebGLByteArray || $G.CanvasByteArray || Array;

  Array.F32 = $G.Float32Array || $G.WebGLFloatArray || $G.CanvasFloatArray || Array;
  Array.F64 = $G.Float64Array || Array;
*/  

var $G = this
  , Float32Array = $G.Float32Array || $G.WebGLFloatArray
  , len =  1000
  , a = new Array(len)
  , b = new Array(len)
  , typedA = new Float32Array(len)
  , typedB = new Float32Array(len)
;  

var _blur =  function(a, b, n)
{
  var lenSub1 = len - 1;
  
  var i = n; while(i--)
  {
    var j = lenSub1; while(--j)
      b[j] = (a[j - 1] + a[j] + a[j + 1])/3;
    var j = lenSub1; while(--j)
      a[j] = (b[j - 1] + b[j] + b[j + 1])/3;
  }    
}

_speedTest(
  [
    function(n)
    {
      _blur(typedA, typedB, n);
    },
    function(n)
    {
      _blur(a, b, n);
    }
  ],
  5000
);

/*
chrome 7 5000
0: 3190 ms
1: 12528 ms

ff4 5000
0: 668 ms
1: 10517 ms

*/