EnemyAttack_Range.cs

using UnityEngine;
using System.Collections;

public class EnemyAttack_Range : MonoBehaviour 
{
	#region Field
	public float  ProjectileSpeed;
	public GameObject hero;
	private Vector3 selfPosition;
	private Vector3 heroPosition;
	private float tmpGetOne;
	#endregion
	
	// initialization
	void Start () {
		//hero = (Hero) GameObject.Find("Hero").GetComponent("Hero");
		hero = GameObject.FindWithTag("Player");
		//destry itself after some time
		StartCoroutine(DestroySelf());
		//when initializated, find self pos and hero pos to get projectile direction
		selfPosition = new Vector3 (transform.position.x, 0, transform.position.z);
		heroPosition = new Vector3 (hero.transform.position.x, 0, hero.transform.position.z);
		tmpGetOne = Mathf.Sqrt((hero.transform.position.x - transform.position.x) * (hero.transform.position.x - transform.position.x) + (hero.transform.position.z - transform.position.z) * (hero.transform.position.z - transform.position.z));


	
	}
	
	// Update is called once per frame
	void Update () 
	{
		float amtToMove = ProjectileSpeed * Time.deltaTime;
		transform.Translate((heroPosition - selfPosition) * amtToMove / tmpGetOne,Space.World );


	}
	//when hit player, call player gothit func
	void OnTriggerEnter(Collider otherObject)
	{
		//Debug.Log ("got hit");

		if (otherObject.tag == "Player")
		{
			otherObject.gameObject.SendMessage("heroGotHit",1);
		}
	}
	//helper function, disappear after some time
	IEnumerator DestroySelf()
	{
		yield return new WaitForSeconds(1.5f);
		Destroy(this.gameObject);
	}
}