Add component to actor in C++ (the final word!)

[Emaer]

@HappyHappyPlay

1. What are the required steps for runtime creation/attachment of components?

It depends on component type

2. If any of those above are optional, why and under which circumstances/for which types of components?

. If your component doesn’t need to “talk” to the
engine (rendering/collision/navigation/replication) then you don’t even need to register it.

Simply put, if a component inherits from USceneComponent then a call to RegisterComponent () is required.

If you want the actor’s transformation to affect the component as well, you need to use AttachTo* function. (implicitly requires registration)

InstanceComponent…
From what I understand, InstanceComponent is just a convention, some standardization of access to “optional” components. Actor does not have to own such a component.

3. Is there any difference for components created in an actor’s constructor, other than creating the component using CreateDefaultSubobject<USceneComponent>("...");

In Actor constructor you can only use CreateDefaultSubobject. This creates a kind of “shape” of a Actor. Adds given component to related UClass, so any instance of this Actor have its ‘by default’. Unlike instanced components, which may only contain certain instances of a given actor.