Extension support is incomplete about unitygltf HOT 6 OPEN

Thanks for bringing this to my attention. Following the "Extensibility" section in the Readme.md, I was able to get an implementation of my extension easily enough. The extension support is looking really good now.

One thing that I didn't see in the documentation was that in order to read data, a user needs an implementation of a GLTF.Schema.ExtensionFactory and that impl needs to be registered in GLTF.Schema.GLTFProperty._extensionRegistry. I just put that registration in my GLTFImportPlugin.CreateInstance() - not sure if there's a better place to do that?

Another piece which was maybe a little strange was the user's ExtensionFactory.Deserialize() method is called for both the root glTF document, as well as the nodes which have the extension, so inside Deserialize(), I needed a heuristic to determine what to parse. Is there a more robust way to determine the what is being deserialized at that point?

Otherwise, it all looks great and I've been able to get the results I wanted. I reckon it's worthwhile adding a sample which shows the full process of extending the loader with some sort of trivial extension. Happy to help out here.

from unitygltf.

There is a new plugin system in the current version. Please take a look :) (Documentation stills lags a bit behind, but more samples are planned)
When you still missing some explicit usecases what do you want to archive, please post it here

from unitygltf.

@eoineoineoin by "to read data" you mean on import to read e.g. extensions on nodes in the GLTF json?

If yes then I don't think you need to register anything to this ExtensionFactory. Here's a snippet from the Needle Engine import plugin to read component data in case it helps:

public override void OnAfterImportNode(Node node, int nodeIndex, GameObject nodeObject)
{
	needleImportContext.Register("/nodes/" + nodeIndex, nodeObject);
	if (node.Extensions != null)
	{
		foreach (var kvp in node.Extensions)
		{
			if (kvp.Value is DefaultExtension defaultExtension)
			{
				var data = defaultExtension.ExtensionData;
				switch (kvp.Key)
				{
					case UnityGltf_NEEDLE_components_Extension.EXTENSION_NAME:
						var ext = data.Children().First() as JObject;
						NeedleComponentsImporter.OnImport(needleImportContext, nodeObject, nodeIndex, ext);
						break;
				}
			}
		}
	}
}

from unitygltf.

Interesting; I am reading extensions on nodes in the JSON. I didn't realise that there was a DefaultExtension which enabled access to the data like that. The reason I ended up with that opinion was from my reading of the Readme.md:

If your plugin reads/writes custom extension data, you need to also implement GLTF.Schema.IExtension for serialization and deserialization.

So I followed the breadcrumbs from there and made my own IExtension; then, the class responsible for instantiating my IExtension was the ExtensionFactory, and in order to get that to run, I needed to register it with the extension registry.

from unitygltf.

Can i close this issue? :)

from unitygltf.

I think a follow-up task here is to update the Readme and provide more complete examples for "how to make your own import and export extensions". If you make a follow-up issue for that and reference this issue here, this issue here can be closed.

from unitygltf.