Huge performance hit when spawning prefab with AI

Questions & Answers
1

Hey guys, I’m working on a simple top-down shooting game, and I just started having some trouble when I began working on spawning zombies into the world. Basically I have an array of spawn points, and when I press a button a random point is picked and a zombie is spawned. The zombie prefab has a basic AI script attached to it (it just chases the player at this point). The problem I have is that as soon as the first zombie spawns, my game takes a huge performance hit (140 fps down to 11-13 when the zombie spawns). I can’t for the life of me figure out what’s happening with it, so any help is appreciated. The zombie AI script is as follows:

#pragma strict

private var target : Transform;
private var moveSpeed : float = 3.0;
private var turnSpeed : float = 3.0;

private var myTransform : Transform;

private var health : float = 100;

function Awake()
{
	myTransform = transform;
}

function Start()
{
	target = GameObject.FindWithTag("Player").transform;
}

function Update()
{
	myTransform.rotation = Quaternion.Slerp(myTransform.rotation, Quaternion.LookRotation(target.position - myTransform.position), turnSpeed * Time.deltaTime);
	myTransform.position += myTransform.forward * moveSpeed * Time.deltaTime;
}

I also have a GameController script attached to an empty GameObject in the world, and it controls the spawning of zombies:

#pragma strict

public var zomPrefab : GameObject;

private var roundNumber : int = 1;
private var Zombies : ArrayList;
private var spawnPoints : GameObject[];


function Start () 
{
	spawnPoints = GameObject.FindGameObjectsWithTag("SpawnPoint");

	Zombies = new ArrayList();
	// var newZom : GameObject = GameObject.Instantiate(zomPrefab, spawnPoints[0].transform.position, Quaternion.identity);
	// Zombies.Add(newZom.gameObject);

	// RenderSettings.ambientLight = new Color(.2, .2, .2, 1);
}

function OnGUI()
{
	GUI.Label(Rect(0, 0, 50, 100), "Round " + roundNumber);
	GUI.Label(Rect(0, 50, 100, 100), "Zombies: " + Zombies.Count);
	// GUI.Box(Rect(0, 0, 50, 100), roundNumber);
}

function Update () 
{
	if(Input.GetKeyDown("tab"))
	{
		NewRound();
	}
}

function NewRound()
{
	roundNumber++;
	SpawnZombie();
}

function SpawnZombie()
{
	var spawnPoint : int = Random.Range(0, spawnPoints.length);

	Debug.Log("Spawning zombie at point " + spawnPoint);

	var newZom : GameObject = GameObject.Instantiate(zomPrefab, spawnPoints[spawnPoint].transform.position, Quaternion.identity);
	Zombies.Add(newZom.gameObject);
}

I know that Instantiate() calls are expensive, but I figured that since I’m not using many that shouldn’t be a huge problem. Any thoughts?

Thanks!!

2

If you have Pro then your first step in diagnosing any performance problem should be to run the Profiler.