3D tiles rendering issue on mobile devices if shadows are enabled

CesiumJS
1

Hi to all

1. I'm facing to a rendering issue of 3d tiles if shadows are enabled (only on mobile device)

Tested on
- mobile: iphone 7
- IOS version: 11.4.1
- browser: safari, chrome

2. It's realy easy to reproduce it just go to sandcasle e.g. https://cesiumjs.org/Cesium/Apps/Sandcastle/index.html?src=3D%20Tiles%20Feature%20Picking.html and simply set shadows to true.

...
var viewer = new Cesium.Viewer('cesiumContainer', {
    terrainProvider: Cesium.createWorldTerrain(),
    shadows: true
});
...

You should get pretty similar result as example below

Does anyone facing the same issue ? Any suggestions ?

Thanks for the reply

2

I think this might be an issue with the limited precision of the depth buffer on iOS devices. See the discussion here:

https://github.com/AnalyticalGraphicsInc/cesium/issues/4752

In particular, the link in this comment.