text: goog.require('ol.Feature');
  goog.require('ol.Map');
  goog.require('ol.Observable');
  goog.require('ol.View');
  goog.require('ol.control');
  goog.require('ol.easing');
  goog.require('ol.geom.Point');
  goog.require('ol.layer.Tile');
  goog.require('ol.layer.Vector');
  goog.require('ol.proj');
  goog.require('ol.source.OSM');
  goog.require('ol.source.Vector');
  goog.require('ol.style.Circle');
  goog.require('ol.style.Stroke');
  goog.require('ol.style.Style');
  
  
  var map = new ol.Map({
    layers: [
      new ol.layer.Tile({
        source: new ol.source.OSM({
          wrapX: false
        })
      })
    ],
    controls: ol.control.defaults({
      attributionOptions: /** @type {olx.control.AttributionOptions} */ ({
        collapsible: false
      })
    }),
    renderer: common.getRendererFromQueryString(),
    target: 'map',
    view: new ol.View({
      center: [0, 0],
      zoom: 1
    })
  });
  
  var source = new ol.source.Vector({
    wrapX: false
  });
  var vector = new ol.layer.Vector({
    source: source
  });
  map.addLayer(vector);
  
  function addRandomFeature() {
    var x = Math.random() * 360 - 180;
    var y = Math.random() * 180 - 90;
    var geom = new ol.geom.Point(ol.proj.transform([x, y],
        'EPSG:4326', 'EPSG:3857'));
    var feature = new ol.Feature(geom);
    source.addFeature(feature);
  }
  
  var duration = 3000;
  function flash(feature) {
    var start = new Date().getTime();
    var listenerKey;
  
    function animate(event) {
      var vectorContext = event.vectorContext;
      var frameState = event.frameState;
      var flashGeom = feature.getGeometry().clone();
      var elapsed = frameState.time - start;
      var elapsedRatio = elapsed / duration;
      // radius will be 5 at start and 30 at end.
      var radius = ol.easing.easeOut(elapsedRatio) * 25 + 5;
      var opacity = ol.easing.easeOut(1 - elapsedRatio);
  
      var style = new ol.style.Style({
        image: new ol.style.Circle({
          radius: radius,
          snapToPixel: false,
          stroke: new ol.style.Stroke({
            color: 'rgba(255, 0, 0, ' + opacity + ')',
            width: 0.25 + opacity
          })
        })
      });
  
      vectorContext.setStyle(style);
      vectorContext.drawGeometry(flashGeom);
      if (elapsed > duration) {
        ol.Observable.unByKey(listenerKey);
        return;
      }
      // tell OL3 to continue postcompose animation
      map.render();
    }
    listenerKey = map.on('postcompose', animate);
  }
  
  source.on('addfeature', function(e) {
    flash(e.feature);
  });
  
  window.setInterval(addRandomFeature, 1000);
  