Another Inlet

_.md

[ Launch Inlet ]
Gist #3200444

config.json

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inlet.js

var domain = d3.range(0,Math.PI,0.1);
var data = [];
for (i in domain) {
  p = domain[i];
  data.push(Math.abs(Math.cos(p)*9.8)*(-1));
}
//console.log(data); // simulate drop data

//http://newcome.wordpress.com/2009/11/04/simple-fourier-transform-in-javascript/
function fourier( in_array ) {
 var len = in_array.length;
 var output = [];
 
 for( var k=0; k < len; k++ ) {
   var real = 0;
   var imag = 0;
   for( var n=0; n < len; n++ ) {
     real += in_array[n]*Math.cos(-2*Math.PI*k*n/len);
     imag += in_array[n]*Math.sin(-2*Math.PI*k*n/len);
   }
   output.push( [ real, imag ] )
 }
 return output;
}


var tscale = d3.scale.linear()
    .domain([0,data.length])
    .range(["#00FF00", "#FF0000"])
    .interpolate(d3.interpolateHsl);

var pr = 12;

function makeCube(t,pos) {
  var col = parseInt(tscale(t).slice(1,7), 16);
  
  var materials = d3.range(6).map(function(d) {
    return new THREE.MeshBasicMaterial( { color: col } )
  })
  var cube = new THREE.Mesh( new THREE.CubeGeometry( pr, pr, pr, 1, 1, 1, materials ), new THREE.MeshFaceMaterial() );
  tributary.scene.add( cube );
  cube.position = pos;
  return cube;
}

var zoom = 9;

var newdata = [];
var mean = d3.mean(data);
    
for (d in data)	{
  var cube = makeCube(d,{x:d*zoom-300, y:data[d]+200 , z:0});
  newdata.push(data[d]-mean);
}

var f = fourier(newdata);
N = data.length;

//http://www.adamsiembida.com/node/23
//http://tech.groups.yahoo.com/group/SeattleRobotics/message/44971
//http://www.edaboard.com/thread107784.html

var locs = [];
for (d in f)	{
  // FFT to x in frequency domain
  var location = Math.abs(f[d][0]) / Math.pow((2*Math.PI*N),2);
  locs.push(location);
}

// inverse fft 1/N*fft to translate frequency back to time domain
ifft = fourier(locs);
locs = []
for (l in ifft) {
  locs.push(ifft[l][0]/N);
}

for (d in locs)	{
  var cube = makeCube(d,{x:d*zoom-300, y:locs[d]-100 , z:0});
}

console.log(data);
console.log(locs);