Unity Pooling System

Custom object pooling system for Unity.

Instead of constantly creating and destroying GameObjects, this system reuses inactive instances to improve runtime performance and reduce garbage collection spikes.

How to use

1. Create a Poolable Prefab

Attach PoolableObject to your prefab.

using ThornDuck.PoolingSystem;
using UnityEngine;

public class Bullet : PoolableObject
{
  private void Awake()
    => OnRetrieveFromPool += Reset;

  private void Reset()
  {
    // Reset state here
  }
}

2. Prewarm the Pool (Optional)

Prewarming creates inactive instances ahead of time to avoid runtime instantiation spikes.

PoolingSystem.Prewarm(bulletPrefab, 50);

3. Spawn Objects

PoolableObject bullet = PoolingSystem.TryGetInstance(
  bulletPrefab,
  spawnPosition,
  spawnRotation
);

If the pool is empty, the system automatically creates a new instance.

4. Return Objects to the Pool

Instead of destroying objects:

PoolingSystem.ReturnInstance(bullet);

The object becomes inactive and is reused later.

Example

public class Gun : MonoBehaviour
{
  [SerializeField] private PoolableObject bulletPrefab;

  private void Start()
    => PoolingSystem.Prewarm(bulletPrefab, 100);

  private void Shoot()
  {
    PoolableObject bullet = PoolingSystem.TryGetInstance(
      bulletPrefab,
      transform.position,
      transform.rotation
    );

    if (bullet == null)
      return;
  }
}

Notes

The system includes built-in safety limits (max number of pools, max number of instances and max instances per prefab). If limits are exceeded, the oldest unused pool is automatically removed and instance creation safely fails.

Warning

Never use Destroy() on pooled instances directly, use PoolingSystem.ReturnInstance() instead. However, if a pooled object is destroyed manually, the system automatically deregisters it safely.