Infinite scroll 2D is really slow with polygons

[hpinkos]

• Open the viewer
• Drag drop the attached GeoJSON file
• Switch to 2D mode

The map is lags pretty badly in 2D infinite scroll mode. The performance is fine in 3D and is much better if you use the rotatable 2D map instead

vienna.geojson.txt

[hpinkos]

@bagnell a number of users on the forum have been complaining about slow polygons when upgrading from 1.2x to 1.30+. Do you know of anything that changed that might have caused that?

[pjcozzi]

@hpinkos do you have links to the forum issues?

@bagnell sounds like something is being computed per-vertex/triangle per-frame. Perhaps it is missing a coarse-grained check?

[hpinkos]

Forum posts:

https://groups.google.com/d/msg/cesium-dev/hXC8gxdi3uE/ZBWHUL6jAgAJ
https://groups.google.com/d/msg/cesium-dev/wT2jkCrvvGQ/WdrP3QgmAwAJ

[hpinkos]

Also reported by @forest21000 in #7694

[ggetz]

Reported again by @zhangchn in #10304.

[zhangchn]

Reported again by @zhangchn in #10304.

The performance issue in SCENE2D could NOT be alleviated by using MapMode2D.ROTATE.

[0dividedby0-b]

I am also seeing this same issue, even with MapMode2D.ROTATE enabled. Lower frame rate and higher CPU usage when 2D is compared to 3D.