Optimize hundreds of objects

Questions & Answers
1

How can i optimize hundreds of objects firing at each other? I’ve already got box colliders because they are the least memory usage by a long shot. everything is fine until i add this part:

void OnTriggerStay(Collider other)
	{
		if (other.tag == "Enemy" )
		{
			if (inTrigger && Time.time > lastFireTime)
			{
				lastFireTime = Time.time + delayTime;
				Fire(other.transform);
			}
		}
		else
			Physics.IgnoreCollision(collider, other.collider);
	}
void Fire(Transform currentTarget)
	{
		GameObject shot = Instantiate(bullet, transform.position, Quaternion.identity) as GameObject;
		shot.GetComponent<BulletPhysics>().target = currentTarget;
		Destroy((shot.gameObject), 2);
	}

basically i think the slowdown is coming from the way i’m doing my delay is there a better way? The profiler states 80k calls is being done in stay in a matter of seconds

2

Two things to keep in mind:

  1. Make sure that all your bullets are using only 1 Draw Call. Read about dynamic batching on Unity.

  2. Use Object Pooling. Search a bit about how to implement it, but the basic idea is to keep a Queue of the object you will be “creating” a lot (bullets). Instead of intantiate every single one (instantiate is slow), deactivate objects that you are no longer using and re-use them again when you need a new instance. For example:

    using System.Collections.Generic;
    
//Pool
private Queue<BulletPhysics> bulletPool = new Queue<BulletPhysics>();
    
public BulletPhysics GetBulletFromPool()
{
   BulletPhysics bullet = null;
    
   if (this.bulletPool .Count == 0)
   {
      bullet = Instantiate(this.bulletPrefab) as BulletPhysics;
   }
   else
   {
      bullet = this.bulletPool .Dequeue();
   }
    
    bullet.gameObject.SetActive(true);
    bullet.Init();
    return bullet;
}
    
public void ReturnBulletToPool(BulletPhysics bullet)
{
   bullet.ClearData();
   this.bulletPool.Enqueue(bullet);
}