title: open layer 3 shape dissapear
body: <p>I'm using Open Layer 3 with Open Street Maps.</p>
  
  <p>I have got a list of specified locations and want to draw lines through each one of them to visualize azimuth and specify line crossing point on map.</p>
  
  <p>To draw lines I'm using ol.styleRegularShape with 2 points and rotation that is calculated from given azimuth.</p>
  
  <p><strong>The problem is that when zooming crossing point, my lines dissapears</strong>. I assume it's happening because base location of each line is out of visible area.</p>
  
  <p>I was trying to change renderer type but it did not help or maybe I did something wrong?</p>
  
  <pre><code>var vectorLayer = new ol.layer.Vector({
  source : source,
  renderer : "WebGL"
  })
  </code></pre>