1. A concise explanation of the problem you’re experiencing.
When multiple imagery layers are added (either via WMTS or multiple static ImageryProvider instances), mobile Safari displays black tiles along the curvature of the Earth.
2. A minimal code example. If you’ve found a bug, this helps us reproduce and repair it.
Just copy/pasted your WMTS sample to jsFiddle because the Cesium Sandcastle interface is not even slightly mobile-friendly. Zoom in to the active area and notice the black tiles appear every once in a while during animation. Always along the curvature of the Earth.
I have a separate implementation where this issue appears after adding multiple (3) static layers (MVT renders or just plain Imagery).
3. Context. Why do you need to do this? We might know a better way to accomplish your goal.
I just finished writing Mapbox Vector Tile support into Cesium on my development version. It exacerbated this bug. However, the above sample is the best way to demonstrate it.
4. The Cesium version you’re using, your operating system and browser.
When you say “used to work fine” do you mean with previous versions of iOS or previous versions of Cesium? Can you try narrowing down which version of Cesium (or even better, which git commit) broke things? That would go a long way to helping us fix the issue.
Just for info, I can still reproduce this today on an iPad Air 2 with iOS 12.1 running Cesium 1.51
When adding an extra imageryLayer using viewer.imageryLayers.add, the base layer shows intermittent missing tiles (black) where the extra layer is loading content.
Thanks for letting us know Xavier. I’m trying to collect more info to open up a GitHub issue (https://github.com/AnalyticalGraphicsInc/cesium) for it. Does this happen for you in this imagery layers Sandcastle:
