title: How to use "OculusRiftEffect.js" on the "webgl_interactive_cubes" examples
body: <p>I was very excited when I first saw this example (<a href="https://github.com/mrdoob/three.js/blob/master/examples/webgl_geometry_minecraft_oculusrift.html" rel="noreferrer">webgl_geometry_minecraft_oculusrift</a>) in <a href="https://github.com/mrdoob/three.js/" rel="noreferrer">mrdoob/three.js · GitHub</a> website. Undoubtedly, it's pretty awesome!</p>
  
  <p>But I'm curious, how to apply this effect on other examples? So I try to implement this effect in the "webgl_interactive_cubes". However, the experimental result is worse than expected.</p>
  
  <p>My problem is that I can't accurately align the cursor to a particular cube to make it change color, seems to be a problem with the projection function? Then I adjusted the screen width coefficient, like this </p>
  
  <blockquote>
    <p>window.innerWidth * 2</p>
  </blockquote>
  
  <p>in the whole program. But still can not improve this problem.</p>
  
  <p>Summary my issue :</p>
  
  <ol>
  <li><p>If I want to apply <em>Oculus Rift Effect</em> on <strong>any example</strong>, how should I do? by th way, I only added the following code </p>
  
  <pre><code>        effect = new THREE.OculusRiftEffect( renderer );
          effect.setSize( window.innerWidth, window.innerHeight );
  
          // Right Oculus Parameters are yet to be determined
          effect.separation = 20;
          effect.distortion = 0.1;
          effect.fov = 110;
  </code></pre>
  
  <p>in initialize block <code>init();</code> and final added <code>effect.render( scene, camera );</code> in <code>render();</code></p></li>
  <li><p>I am very curious to know how</p>
  
  <p><code>var vector = new THREE.Vector3( mouse.x, mouse.y, 1 );
  projector.unprojectVector( vector, camera );</code> </p>
  
  <p>works. Why do need to pass parameter 1? what if I change <code>mouse.x</code> to <code>mouse.x * 2</code></p></li>
  <li><p>Need to use dual monitors can only be fully present this effect?</p></li>
  </ol>
  
  <p>Note: My English is not very good, if I have described is unclear, please ask your doubts, I will respond as soon as possible.</p>
  
  <p>This is my DEMO link:</p>
  
  <ol>
  <li><p><a href="http://goo.gl/VCKyP" rel="noreferrer">http://goo.gl/VCKyP</a></p></li>
  <li><p><a href="http://goo.gl/xuIhr" rel="noreferrer">http://goo.gl/xuIhr</a></p></li>
  <li><p><a href="http://goo.gl/WjqC0" rel="noreferrer">http://goo.gl/WjqC0</a></p></li>
  </ol>
  
  <p>My Folder : <a href="https://googledrive.com/host/0B7yrjtQvNRwoYVQtMUc4M1ZZakk/" rel="noreferrer">https://googledrive.com/host/0B7yrjtQvNRwoYVQtMUc4M1ZZakk/</a></p>