title: Use heatmap.js in cesium.js
body: <p>I'm interested in showing a heatmap in my Cesium application. On the <a href="http://www.patrick-wied.at/static/heatmapjs/" rel="noreferrer">heatmap.js website</a> they have a number of demos such as the <a href="http://www.patrick-wied.at/static/heatmapjs/example-heatmap-leaflet.html" rel="noreferrer">leaflet demo</a> which adds the heatmap object as a layer. I'm wondering if there is a way to do such a thing in Cesium.js. I've seen people mention rendering a (or multiple) PNG(s) and showing that as a layer, that's a viable option if there is a way that I can do it on the fly and add them to my Cesium instance.</p>
  
  <p>I have seen <a href="https://youtu.be/81l6gdSo-10?t=7m" rel="noreferrer">examples of heatmaps in Cesium</a> but it's never explained how they did that (I don't even know if they used heatmap.js). There is also an issue on the <a href="https://github.com/AnalyticalGraphicsInc/cesium/issues/2208" rel="noreferrer">Cesium.js GitHub</a> about this, but they don't seem to be actively pursuing it.</p>