Directory structure issues

[emackey]

I think some of the recent merges have created problems.

$ ./generate-index.py
WARNING: no model files found for DirectionalLight
WARNING: no screenshot found for SheenDamask
WARNING: no screenshot found for XmpMetadataRoundedCube

[DRx3D]

I checked DirectionalLight and did find a model file. How/what/where is generate-index.py looking for model files?

SheenDamask and XmpMetadataRoundedCube do not have files called screenshot/screenshot.[jpg|png]. I'll push up the missing screenshots.

[javagl]

The DirectionalLight issue was most likely due to the directory names being gltf and gltf-Binary instead of glTF and glTF-Binary. Fix in #397

[DRx3D]

Screenshots and binary (for XMP...) files were created. Please review @emackey .

[emackey]

Looks good. No warnings from generate-index.py.