Custom extensions?

Hi, this is a wonderful project, thank you!

Is there any way I can add my own glTF extensions from a client app, without modifying the library itself?

For example if I wanted a particular node to have an extension AGI_testing with a value "itWorks" : true in my exported glTF, can I do that without modifying SharpGLTF? Or what’s the smallest mod I would need to make?

[vpenades]

It’s something I have planned, but I’ve never tested it. Mostly because extensions usually imply changing things in the code… and data only extensions can easily be simulated with the extras.

Nevertherless, the way to make the library aware of an extension is by registering it here.

Notice the ExtensionsFactory class is still internal, so you’ll have to call it by reflection, or fork the library and make it public.

The extension classes are usually generated from the schemas using the builder tool in the project, but it’s also possible to write a class by hand.

About the class itself, I would suggest you to look into the KHR_materials_unlit class, which is the closest thing you can look for.

You have to remember to inherit from ExtraProperties class, add the appropiate contructor (even if it’s empty, it’s called by the deserializer), and add the appropiate read/write serialization methods.

Assuming you’ve been able to do all that, you can just call UseExtension<AGI_Testing_Extension>() on the object you want it to use the given extension.

[emackey]

This is excellent advice, thank you.

I’ve confirmed that the recent commit to master (along with the internal constructor) fixes the original issue here, so I’ll close this.