How to manage input state in Unity3D?

Question

In Unity3D how do I manage input among many components, especially in relation to "blocking" input messages to certain components?

To make my question clear, an example:

Component 1: Input Manager

Manages a list of components that require input. They do this via a Register method, which adds the component to a List. Each registered component can poll input via this method:

public static bool GetKeyUpAndActive(KeyCode keyCode, MonoBehaviour entity) {
    return Input.GetKeyUp(keyCode) && List.Contains(entity);
}

This feels clunky, as each entity needs to pass itself to the manager, and the manager has to keep a list of registered input events.

Component 2: Script Manager

Manages scripts such as "Open Dialogue Box, say "Hello", play SFX, add Item x to inventory. Script manager responds to input, for example, if over component, and Input.Action is pressed, run this script.

Component 3: Dialogue Manager

Manages the dialogue box, pretty stock standard stuff. It also responds to input, pressing Input.Action will cycle through the dialogue boxes, until it reaches the end, then returns back to the game.

The main issue I am facing is that the script manager and the dialogue manager are responding to the Input.Action during their own updates. So Script 001 responds to Input.Action which triggers an open dialogue box, but because dialogue manager also responds, it has already cycled through to the next dialogue box.

I think the Input Manager is breaking encapsulation. I also feel like I'm missing an obvious component here, maybe I need a stronger subscriber pattern to follow, or should there be a separate state manager, and if so, should the input manager only send events/provide methods to components in the correct state, or should components check the state machine themselves?

Answer 1

Hey I will try to give you a starting point. Your problem of handling the input in more than one method could be solved by creating your own small messaging system:

• Create a class InputMessage, this class contains the original Input action and a bool handled.

• Your Input handler is the only class to access the original Unity Input, whenever a input occurs it generates a new InputMessage, encapsuling the original action.

• Components can register to the input manager (just like you already handle it), maybe with the extend to provide a priority, indicating how 'early' it should be processed.

• When a new InputMessage is created the input manager pass it to every component in the list, into a function InputMessage TakeInput(InputMessage im)

• This function will handle input logic nd then return the original message, or an altered one, this new message is then passed to the next component, unless it got handled set to true

So in your problem you would just set handled to true in the script manager and return the message. Your InputManager would see this and break the loop. You could even use this system to change input messages in your components, if you ever need to do so.

Logic in InputManager could look somehow like this:

InputMessage im=new InputMessage(originalAction,false);
foreach(InputComponent ic in list){
  im=ic.TakeInput(im);
  if(im.Handled)
    break;
}

InputComponent would we an interface or abstract class adding the Takeinput function to your class signature.

Hope this gets you started, feel free to comment, if you got any questions