I am working on a team-based shooter where you mainly control a single PlayerAgent, which is a subclass of Agent. AI, localplayers and networkplayers all go though this inherited scene(object). However there is also an RTS mode that may be a part of the final game where you control many units. (it will still help with AI debugging) The controlled player can interact with the teams buildings, vehicles, deployables etc.

Favouring composition over inheritance tells me that rather then "Selectable", "Interactable" in a class hierarchy, I make them as child nodes of each object.

I have an interactable component that detects a raycast collision. The controlled player is near a building, it hits, I walk up the tree to find a common interface of objects. But one doesn't exist due to flat composition. I then guess I should set an internal signal of each object to find its "interactable" and "selectable" components, to be able to have the player to activate (select) a particular selectable. And then in RTS mode, I could then exploit this to have multiple objects selected at a time. This still seems wild to have many of the same invidual signals local inside each object, to broadcast to the "building" or "vehicle" scene root, "I am selected", then modulate some colour.

I am trying to get my head around the godot way. I feel as though there is a little argument to be made for a minor level of inheritance. Surely

- GameObject - Selectable (interface) - Building class (uses interface) - composition components - Vehicle class (uses interface) - composition components. 

Here there is some inherited tree structure to allow my game objects to use a common interface and to know where they sit in the pecking order, or am I looking at this completely wrong?

Maybe the signal doesn't go up to the individual classes but past them into the map/level root and into some higher level object which manages whats selected? that way single/multiple selection exists? Are there any RTS godot games that I can peak into