title: Three.js - Depth of field
body: <p>I'm trying make depth of field in my project and I'm inspired from official three.js example like this <a href="https://threejs.org/examples/webgl_postprocessing_dof.html" rel="nofollow noreferrer">https://threejs.org/examples/webgl_postprocessing_dof.html</a></p>
  
  <p>I have problem with method BokehPass. There is my code:</p>
  
  <pre><code>const bokehPass = new THREE.BokehPass( this.scene, this.camera, {
    focus: 1.0,
    aperture: 0.025,
    maxblur: 1.0,
    width: window.innerWidth,
    height: window.innerHeight
  } );
  </code></pre>
  
  <p>and when I want to initialize it I have error:</p>
  
  <pre><code>Uncaught TypeError: Cannot set property 'value' of undefined
  </code></pre>
  
  <p>It's error from third param in this method. Does someone have any idea what's wrong with it?</p>