topojson datasource - high cpu ?

1. A concise explanation of the problem you're experiencing.

A 100kb topojson datasource causes very high cpu usage when nothing is rendering, performance tab shows no cpu or fps, while task manager tab shows high cpu and memory usage increase at 5MB per second

2. A minimal code example. If you've found a bug, this helps us reproduce and repair it.

viewer = new Cesium.Viewer(‘cesiumContainer’,{requestRenderMode: true});
viewer.dataSources.add(Cesium.GeoJsonDataSource.load(‘https://raw.githubusercontent.com/deldersveld/topojson/master/world-countries.json’));

3. Context. Why do you need to do this? We might know a better way to accomplish your goal.

Should not be draining the cpu / memory leak while nothing is rendering

4. The Cesium version you're using, your operating system and browser.

Cesium 1.56.1
Chrome 73.0.3683.103 (Official Build) (64-bit) Windows

chrome_PdLnYer2pm2.png

I think this issue may be due to the antarctica shape in the file, is there some bug with shapes around the pole, or is that datasource topojson file badly formed? If I try with the sans-antarctica version there is no issue:

https://github.com/deldersveld/topojson/blob/master/world-countries-sans-antarctica.json

These topojson files are from this github repo: https://github.com/deldersveld/topojson

So now that I found I can use the sans-antarctica version and not have the issue anymore I don't have a problem, but maybe something to look into for the devs, or possibly bad topojson file

Thanks for sharing this! This does look like it’s worth investigating. When I tried it I notice the sans Antarctica version seemed to be filled in polygons, whereas the complete world one was just outlines. Is that intentional? Did you try comparing one with the same kind of geometry but just with/without Antarctica?