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Functions

Any Kotlin, Java, or Scala function can be registered as long as its parameters and return type can be converted to a Variant. To register a function annotate it with @RegisterFunction.

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@RegisterClass
class RotatingCube : Node3D() {
    @RegisterFunction
    override fun _ready() {
        println("I am ready!")
    }
}

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@RegisterClass
public class RotatingCube extends Node3D {
    @RegisterFunction
    @Override
    public void _ready() {
        System.out.println("I am ready!");
    }
}

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@RegisterClass
class RotatingCube extends Node3D {
  @RegisterFunction
  override def _ready(): Unit = {
    println("I am ready!")
  }
}

Naming

Function names should follow the usual style of the language you use. For consistency with Godot's style, your functions are actually registered as snake_case. Therefore, a function called doSomething() is usable in GDScript as do_something().

Virtual functions

Virtual functions (like _ready, _process and _physics_process) are declared as overridable functions. The default implementation throws a NotImplementedException, so you have to override it if you plan to expose a virtual function to Godot. Remember, just overriding is not enough to use that function - you have to explicitly register it as well with @RegisterFunction.

Arguments count

Godot limits the allowed argument count of functions to 16. Thus, this binding also has this limitation. If you want to pass more than 16 parameters in a function, you need to wrap them in a container (like a custom container class or a VariantArray or Dictionary).

Customization

You can customize to some extent how your functions should be registered in Godot. The @RegisterFunction annotation takes one argument:

  • rpcMode: Default: RPCMode.DISABLED