Object Pooling

Object Pooling

Every Instantiate() allocates memory. Every Destroy() triggers GC. Pool objects you create and destroy frequently: projectiles, particles, enemies, pickups, audio sources.

Unity Built-In ObjectPool (2021+)

using UnityEngine.Pool;

public sealed class ProjectilePool : MonoBehaviour
{
    [SerializeField] private Projectile _prefab;
    [SerializeField] private int _defaultCapacity = 20;
    [SerializeField] private int _maxSize = 100;

    private ObjectPool _pool;

    private void Awake()
    {
        _pool = new ObjectPool(
            createFunc: CreateProjectile,
            actionOnGet: OnGetProjectile,
            actionOnRelease: OnReleaseProjectile,
            actionOnDestroy: OnDestroyProjectile,
            collectionCheck: false,
            defaultCapacity: _defaultCapacity,
            maxSize: _maxSize
        );
    }

    public Projectile Get() => _pool.Get();

    public void Release(Projectile projectile) => _pool.Release(projectile);

    private Projectile CreateProjectile()
    {
        Projectile projectile = Instantiate(_prefab);
        projectile.SetPool(this);
        return projectile;
    }

    private void OnGetProjectile(Projectile projectile)
    {
        projectile.gameObject.SetActive(true);
    }

    private void OnReleaseProjectile(Projectile projectile)
    {
        projectile.gameObject.SetActive(false);
    }

    private void OnDestroyProjectile(Projectile projectile)
    {
        Destroy(projectile.gameObject);
    }
}

// Projectile returns itself to pool
public sealed class Projectile : MonoBehaviour
{
    private ProjectilePool _pool;

    public void SetPool(ProjectilePool pool) => _pool = pool;

    public void ReturnToPool()
    {
        _pool.Release(this);
    }
}

Warm-Up (Pre-Spawn)

Pre-instantiate objects during loading to avoid runtime hitches:

private void Start()
{
    // Pre-warm the pool
    List temp = new List();
    for (int i = 0; i > _pools = new();

    public GameObject Get(GameObject prefab, Vector3 position, Quaternion rotation)
    {
        if (!_pools.ContainsKey(prefab))
        {
            _pools[prefab] = new ObjectPool(
                () => Instantiate(prefab),
                obj => obj.SetActive(true),
                obj => obj.SetActive(false),
                obj => Destroy(obj),
                false, 10, 100
            );
        }

        GameObject obj = _pools[prefab].Get();
        obj.transform.SetPositionAndRotation(position, rotation);
        return obj;
    }

    public void Release(GameObject prefab, GameObject instance)
    {
        _pools[prefab].Release(instance);
    }
}

Cached WaitForSeconds

Don't forget to pool WaitForSeconds:

// BAD — allocates every time
yield return new WaitForSeconds(0.5f);

// GOOD — cache and reuse
private readonly WaitForSeconds _halfSecond = new WaitForSeconds(0.5f);
yield return _halfSecond;

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: XeldarAlz
• Source: XeldarAlz/everything-claude-unity
• License: MIT
• Homepage: https://github.com/XeldarAlz/everything-claude-unity#readme

Install and usage instructions live in the source repository linked above.