Invalid requests sent out for voxel content

[javagl]

What happened?

CesiumJS is sending out invalid requests for voxel data. It is requesting data that is not available (even when it is declared to not be available!), resulting in 404s.

Reproduction steps

• Open the "Voxels" Sandcastle at https://sandcastle.cesium.com/index.html?src=Voxels.html
• Select "Box - 3D Tiles" from the menu (or any other "3D Tiles" flavor, FWIW)
• Look at the console. It will result in several messages
  GET https://sandcastle.cesium.com/SampleData/Cesium3DTiles/Voxel/VoxelBox3DTiles/tiles/1/1/0/1.json 404 (Not Found)

I started zooming into that, and think that it is likely related to this line:

cesium/packages/engine/Source/Scene/Cesium3DTilesVoxelProvider.js

Line 457 in 6c462b7

: subtree.tileIsAvailableAtCoordinates(tileCoordinates);

: It is checking the tile availability with tileIsAvailableAtCoordinates, and based on that, it is requesting content with getVoxelContent (but that's only a hunch, and has to be confirmed).

(A similar issue was fixed via f1b5f8d, but I don't know in how far this is related)

This came up via the forum at https://community.cesium.com/t/3d-tiles-1-1-voxel/32239

Sandcastle example

See above

Environment

Browser: Any
CesiumJS Version: 1.117
Operating System: Any

[ggetz]

@jjhembd Could you please triage?

[ggetz]

Hi, @jjhembd – Just a reminder to please take a look and triage this issue.