How do you remove health of multiple enemies? - unity3d

Question

using System.Collections;
public class TowerAttack : MonoBehaviour {
public float timeBetweenAttacks = 0.5f;
public int attackDamage = 10;
GameObject player;
PlayerHealth playerHealth;
bool playerInRange;
float timer;
void Awake()
{
player = GameObject.FindGameObjectWithTag ("Player");
playerHealth = player.GetComponent<PlayerHealth> ();
}
void OnTriggerEnter(Collider other)
{
print (other);
if (other.gameObject == player)
playerInRange = true;
}
void OnTriggerExit(Collider other)
{
if (other.gameObject == player)
playerInRange = false;
}
// Update is called once per frame
void Update () {
timer += Time.deltaTime;
if (timer >= timeBetweenAttacks && playerInRange)
Attack ();
if (playerHealth.currentHealth <= 0)
print ("Player's dead");
}
void Attack()
{
timer = 0f;
print (playerHealth);
if (playerHealth.currentHealth > 0)
playerHealth.TakeDamage (attackDamage);
}
}
I am using this code on an object called tower and it has box collider with istrigger active. There are multiple objects spawn on the field with "PlayerHealth" script attached and tagged as "Player". However only the first "Player" which enter the box collider get its health remove and the rest of the "Player" objects stay healthy.

Answer 1

There are multiple objects spawn on the field with "PlayerHealth"
script attached and tagged as "Player". However only the first
"Player" which enter the box collider get its health remove and the
rest of the "Player" objects stay healthy.
The playerHealth = player.GetComponent<PlayerHealth> (); line of code will only get the PlayerHealth from one object only.
To remove health from multiple enemies, you need to perform other.GetComponent<PlayerHealth> () each time OnTriggerEnter is called.
void OnTriggerEnter(Collider other)
{
print(other);
//Remove health only if the Object is tagged as Player
if (other.CompareTag("Player"))
{
other.GetComponent<PlayerHealth>().TakeDamage(attackDamage);
playerInRange = true;
}
}

Answer 2

player = GameObject.FindGameObjectWithTag ("Player");
This is for setting one player. If there are multiple player, one of players is set to the variable. playerHealth = player.GetComponent<PlayerHealth> (); is also only the player. You should do like below.
using System.Collections;
public class TowerAttack : MonoBehaviour
{
public float timeBetweenAttacks = 0.5f;
public int attackDamage = 10;
GameObject[] players;
bool playerInRange;
float timer;
void Awake()
{
players = GameObject.FindGameObjectsWithTag ("Player");
// FindGameObjectWithTag => FindGameObjectsWithTag
}
void OnTriggerEnter(Collider other)
{
print (other);
if (other.tag == "Player")
playerInRange = true;
}
void OnTriggerExit(Collider other)
{
if (other.tag == "Player")
playerInRange = false;
}
void Update ()
{
timer += Time.deltaTime;
if (timer >= timeBetweenAttacks && playerInRange)
Attack ();
for (int i = 0; i < players.Length; i++)
{
if (players [i].GetComponent<PlayerHealth> ().currentHealth <= 0)
print ("Player's dead")
}
}
void Attack()
{
timer = 0f;
print (playerHealth);
if (playerHealth.currentHealth > 0)
playerHealth.TakeDamage (attackDamage);
}
}
If you want to make the TowerAttack Attack() all players in range at the same time, you can apply the code above. But, if you want to attack players one after another, move the function in Update() to OnTrigger* methods. Then you may need this method OnTriggerStay.