Support for validation of extension "EXT_structural_metadata"

[aneeq-ur-rehman4]

There is no support for 'EXT_structural_metadata' extension.

"issues": {
      "numErrors": 0,
      "numWarnings": 0,
      "numInfos": 2,
      "numHints": 0,
      "messages": [
          {
              "code": "UNSUPPORTED_EXTENSION",
              "message": "Cannot validate an extension as it is not supported by the validator: 'EXT_structural_metadata'.",
              "severity": 2,
              "pointer": "/extensionsUsed/0"
          },
          {
              "code": "UNUSED_OBJECT",
              "message": "This object may be unused.",
              "severity": 2,
              "pointer": "/bufferViews/4"
          }
      ],
      "truncated": false
  },

[javagl]

This extension is currently only defined in a pull request (meaning that it is not officially released, and certainly not ratified). It also has some complexities and open questions when it comes to how it should be validated. It is unlikely that support for this extension will be added here any time soon.

But... ... there is some support for validating this extension in the 3d-tiles-validator. This is actually intended for 3D Tiles, but that includes the validation of content files like glTF. The 3D Tiles Validator calls the glTF Validator for each content file. And it additionally performs a validation of the EXT_structural_metadata.

You can run this on a single glTF file with

npx 3d-tiles-validator -f example.glb

Note that the report will still contain the UNSUPPORTED_EXTENSION message. The task to filter out these messages is currently in progress.