Fix contentAvailability structure in Implicit3DTileContentSpec #12596

[Vamonosraza]

Description

This PR fixes issue #12596 by updating the Voxel spec data to use the array format for contentAvailability as required by the latest 3D Tiles 1.1 specification.

The change make sure that test files follow the current specification while maintaining backward compatibility with the existing code that handles both formats.

I verified the changes by running the affected tests, which all passed successfully.

Issue number and link

#12596

Testing plan

Author checklist

• I have submitted a Contributor License Agreement
• I have added my name to CONTRIBUTORS.md
• I have updated CHANGES.md with a short summary of my change
• I have added or updated unit tests to ensure consistent code coverage
• I have updated the inline documentation, and included code examples where relevant
• I have performed a self-review of my code

[github-actions]

Thank you for the pull request, @Vamonosraza!

✅ We can confirm we have a CLA on file for you.

[Vamonosraza]

What am I missing?

[javagl]

There's not necessarily something missing in terms of the checklist. It may take a moment until a PR is reviewed and merged, though.

• The changes that you have done in Update CONTRIBUTORS.md #12667 can also be done in this PR (meaning that the other one could become obsolete).
• I think that the glsl code block in the CHANGES.md is not necessary. (In fact, one could argue whether this should be mentioned in the CHANGES.md at all)

More importantly, regarding the fix itself: I've seen that you updated the quadtreeJson that was defined in the Implicit3DTileContentSpec.js. That makes sense, and should probably be part of this PR.

But the issue actually referred to the JSON files that are loaded as part of the specs, namely the files

• https://github.com/CesiumGS/cesium/blob/4dfda79c33b7f743f0661109ad86decf7a1edd0b/Specs/Data/Cesium3DTiles/Voxel/VoxelBox3DTiles/subtrees/0/0/0/0.json
• https://github.com/CesiumGS/cesium/blob/4dfda79c33b7f743f0661109ad86decf7a1edd0b/Specs/Data/Cesium3DTiles/Voxel/VoxelCylinder3DTiles/subtrees/0/0/0/0.json
• https://github.com/CesiumGS/cesium/blob/4dfda79c33b7f743f0661109ad86decf7a1edd0b/Specs/Data/Cesium3DTiles/Voxel/VoxelEllipsoid3DTiles/subtrees/0/0/0/0.json

[ggetz]

@Vamonosraza Any update here? Can you please move the CONTRIBUTORS.md change to this PR and update CHANGES.md to match the next release on August 1?

[mzschwartz5]

Hi @Vamonosraza, I'm going to close this PR since we haven't seen any activity in a little while - but if you come back to it, please feel free to reopen the PR and continue the discussion. Thanks!