如何获得预制件的统一地位？

Question

I want to rotate tank face to moving enemy direction, and I need position of enemy .

enemy.transform.position; works when enemy is in the Hierarchy, but my enemy is in the Prefabs and following code not work. please help :)

using UnityEngine;
using System.Collections;

public class RotateTank : MonoBehaviour {
public GameObject enemy;

void Update () {
    faceTank ();
}

void faceTank(){

    Vector3 enemyPosition;

    enemyPosition = enemy.transform.position;


    Vector2 direction = new Vector2 (
                             enemyPosition.x - transform.position.x,
                             enemyPosition.y - transform.position.y

                         );

    transform.up = direction;
}
}

Answer 1

A prefab does not exist in the game world. Prefabs are "templates" that can be instantiated. If what you want to do is make your tank rotate towards any enemy that exists in the game world, you'll need to reference those GameObjects in your RotateTank script. You could do this a number of ways, such as adding an 'Enemy' tag to your enemy prefab and using GameObject.FindGameObjectsWithTag to find spawned Enemies. You could also have a static List<GameObject> in your RotateTank script that holds references to existing enemies, and add them to that list when they spawn and remove them when they die.