Filament incompatible with sanctioned glb models

[tellypresence]

As mentioned on khronos site, the kenney models "tower defense kit" fail to load due to filament error, e.g. for towerRound_sampleF.glb:

 E/Filament: Unable to parse glb file.

with throwable CompletionException:

java.lang.IllegalStateException: Failed to load gltf

[romainguy]

I can reproduce the issue. Would you mind filing an issue here please: https://github.com/google/filament/issues? The root cause seems to be that cgltf (the glTF parser we use) itself is having issues. We've made contributions to cgltf before so we can fix this ourselves.

CC @prideout

[prideout]

This asset is non-conformant because the scene is defined by a non-root node. According to the spec:

All nodes listed in scene.nodes array must be root nodes 

cgltf checks for this violation and bails. (it checks for this incgltf_fixup_pointers)

[tellypresence]

Done: https://github.com/google/filament/issues/2443