Add a way to add extra functionality to built-in classes using GDExtension

[peachey2k2]

Describe the project you are working on

TL;DR: The built-in tween system doesn't work for me and I want to implement my own into every class. I tinkered with it a bit, but it didn't go anywhere.

First of all, I'm not very experienced with C++ nor GDExtension. There might be a way to do this. If so, sorry.

I'm working on some sort of a video editor plugin. Basically, the idea is that instead of separate video files, the user can use built-in nodes in Godot. I also want to make it so each node can decide when to do what, using a tween-like system. I can't use the built-in tween system for reasons such as:

1. They're one-time use, meaning the preview panel would be super buggy.
2. They aren't customizable enough for my purposes.
3. They aren't very efficient in mass quantities.

This isn't a problem for me, I had already made a tween system in the past for another project. The problem is I couldn't figure out a way to add it to the engine. I basically want to add a function into the Object class, so that it can be inherited by any other class. I then would have a class with access to that object, along with everything exposed within it. To do this however, I messed around with it quite a lot, mainly with #include_next, but couldn't get it to work in any way.

Describe the problem or limitation you are having in your project

I want to add a new function into the built-in Object class, so that it can be used in any other class. I recall doing something similar in C#, but couldn't find a way in here.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

As opposed to C#, there is no partial keyword in C++ (thanks Bjarne Stroustrup). I can't really think of a way to get through that. Perhaps a way to bind methods to any class would work.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

Like how we bind methods like how we do it right now, but for any class. I don't really have an idea how that'd work in code though.

If this enhancement will not be used often, can it be worked around with a few lines of script?

No as far as I know.

Is there a reason why this should be core and not an add-on in the asset library?

Yes, there could be a lot of use cases for something like this.

[Zireael07]

Another use case would be extending the built in Geometry or Astar, to better handle graphs

[AThousandShips]

Related:

• Allow users to modify pre-existing classes (nodes) without recompiling the engine #7068
• Allow modification of engine's types via scripts on runtime #1167