Setting the Type of a variable at runtime

Unity Engine
1

I have a class called BossMovement that I’m using as a universal movement script for multiple bosses. Each boss has it’s own real movement script/class which is named after itself. I have a variable in the BossMovement class that needs to hold a reference to the real movement class for the specific boss that it’s attached to. The problem is that each of the different real movement classes is just that, a different class, thus they each have a different type. I tried to set the reference variable as a MonoBehaviour, but ran into the typecasting problem of not knowing or having a way to hold onto the type of class that’s being set. Here’s an example,

// Universal Movement script
public class BossMovement : MonoBehaviour {
      MonoBehaviour referenceScript;

      public void Setup(MonoBehaviour script)
      {
            referenceScript = script;
      }
}
// Boss 1's Real Movement script
public class BossOneMovement : MonoBehaviour {
      void Start()
      {
            ((BossMovement)gameObject.GetComponent("BossMovement")).Setup(this);
      }
}
// Boss 2's Real Movement script
public class BossTwoMovement : MonoBehaviour {
      void Start()
      {
            ((BossMovement)gameObject.GetComponent("BossMovement")).Setup(this);
      }
}

Boss1 has his own GameObject with BossOneMovement and BossMovement as components and Boss2 has his own GameObject with BossTwoMovement and BossMovement as components.

Is there a working/better way for the BossMovement class to reference the movement script of the Boss it’s currently attached to (without having a switch statement with a string of that boss’s name, each time I need to make a reference)?

2

Use class inheritance; make your BossXMovement scripts extend BossMovement.

If B extends A, and you do this on an object with a B attached:

var anAObject = GetComponent(A);

You’ll get a reference but it will try to call B’s versions of functions before A’s.

3

So, are you saying not to have BossMovement on the objects at all? That returns to the original problem of external scripts not having a Universal script to call. Right now I have multiple external scripts getting the gameObject and then calling BossMovement to either slow or stop the boss. If I have different movement scripts for each boss, this same problem will occur inside each of the external scripts instead of just BossMovement.

4

No, he said you should use inheritance.

public abstract class BossMovement : MonoBehaviour {
    public abstract void Move(Vector3 position); // no method body because it's abstract
}

public class BossAMovement : BossMovement {
    public override void Move(Vector3 position) {
        // add your code for Boss A movement
    }
}

public class BossBMovement : BossMovement {
    public override void Move(Vector3 position) {
        // add your code for Boss B movement
    }
}


BossMovement boss = GetComponent<BossMovement>(); // you don't have to know if it's BossAMovement or BossBMovement type, BossMovement abstract class makes sure that Move method is always implemented

boss.Move(new Vector3(10, 20, 30)); // Move the boss to the position x=10, y= 20 z=30
5

Something like this, then?

class BossMovement {
  static function Setup( boss : BossMover ) {
    // do stuff
  }
}

class BossMover extends MonoBehaviour {
  function Start() { Init(); }
  function Init() { BossMovement.Setup( this ); }
}

class Boss1Mover extends BossMover {
  function Init() {
    super.Init(); // calls BossMover.Init()
    // do other stuff
  }
}

class Boss2Mover extends BossMover {
  function Init() {
    super.Init();
    // do different other stuff
  }
}