Nfy VS assimp

For me, the answer is a generic multicast notification system. It utilizes a template based approach that allows you to define prototype messages using a class-based interface that you wish to send to another library. For example, your input library might respond to things like a button down / up, mouse clicks, etc, etc. So you'd create an interface that defines all your input notifications as functions. I won't go into detail, because it's well documented in that link.

In my own code, I make use a generic notification system which allows high-level systems to register themselves with lower-level libraries to help invert dependencies. An example of this is how my game engine's UI library can register itself with the Input library, so it can receive mouse, keyboard, and gamepad events, necessary for manipulating UI controls. But the Game itself also needs to register for some UI events itself, not to mention debug functionality like ImGui for debug windows, etc. So I use this notification system to ensure the low-level Input library can push events out to multiple subscribers without needing to know about them.

See if this is close to what you're looking for: https://github.com/JamesBoer/Nfy

If you use something like libassimp https://github.com/assimp/assimp it will allow you to import these and access the data to generate your Vertex Array Objects then render to a frame buffer object.

If you just want to load other data in a relatively simple fashion, assimp https://www.assimp.org supports loading a bunch of different formats and is pretty easy to use.

The emscripten interface for the assimp library. It runs entirely in the browser, and allows you to import 40+ 3D file formats and access the result in JSON or glTF format. This is not a full port of assimp, but an easy to use interface to access it's functionality.

I ran into what sounds like a similar problem a few months ago. It turns out this was an assimp bug: https://github.com/assimp/assimp/issues/1974

You could give assimp a go (there is a python version) i've used it for 3DS before then you can export to something else. https://github.com/assimp/assimp/blob/master/port/PyAssimp/README.md

I have checked the source code for GLTF for this and it is not handled by Assimp. I created an issue as in their Github.

Assimp is your friend

Have you read the license? It's quite permissive. https://github.com/assimp/assimp/blob/master/LICENSE

There is probably some library more specific to your use case, but you can use assimp to load 3d models in C++.