Version: 2021.2
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ObjectPool<T0>.Get

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Declaration

public T Get();

Returns

T A pooled object or a new instance if the pool is empty.

Description

Get an instance from the pool. If the pool is empty then a new instance will be created.

using System.Text;
using UnityEngine;
using UnityEngine.Pool;

// This component returns the particle system to the pool when the OnParticleSystemStopped event is received. [RequireComponent(typeof(ParticleSystem))] public class ReturnToPool : MonoBehaviour { public ParticleSystem system; public IObjectPool<ParticleSystem> pool;

void Start() { system = GetComponent<ParticleSystem>(); var main = system.main; main.stopAction = ParticleSystemStopAction.Callback; }

void OnParticleSystemStopped() { // Return to the pool pool.Release(system); } }

// This example spans a random number of ParticleSystems using a pool so that old systems can be reused. public class PoolExample : MonoBehaviour { public enum PoolType { Stack, LinkedList }

public PoolType poolType;

// Collection checks will throw errors if we try to release an item that is already in the pool. public bool collectionChecks = true; public int maxPoolSize = 10;

IObjectPool<ParticleSystem> m_Pool;

public IObjectPool<ParticleSystem> Pool { get { if (m_Pool == null) { if (poolType == PoolType.Stack) m_Pool = new ObjectPool<ParticleSystem>(CreatePooledItem, OnTakeFromPool, OnReturnedToPool, OnDestroyPoolObject, collectionChecks, 10, maxPoolSize); else m_Pool = new LinkedPool<ParticleSystem>(CreatePooledItem, OnTakeFromPool, OnReturnedToPool, OnDestroyPoolObject, collectionChecks, maxPoolSize); } return m_Pool; } }

ParticleSystem CreatePooledItem() { var go = new GameObject("Pooled Particle System"); var ps = go.AddComponent<ParticleSystem>(); ps.Stop(true, ParticleSystemStopBehavior.StopEmittingAndClear);

var main = ps.main; main.duration = 1; main.startLifetime = 1; main.loop = false;

// This is used to return ParticleSystems to the pool when they have stopped. var returnToPool = go.AddComponent<ReturnToPool>(); returnToPool.pool = Pool;

return ps; }

// Called when an item is returned to the pool using Release void OnReturnedToPool(ParticleSystem system) { system.gameObject.SetActive(false); }

// Called when an item is taken from the pool using Get void OnTakeFromPool(ParticleSystem system) { system.gameObject.SetActive(true); }

// If the pool capacity is reached then any items returned will be destroyed. // We can control what the destroy behavior does, here we destroy the GameObject. void OnDestroyPoolObject(ParticleSystem system) { Destroy(system.gameObject); }

void OnGUI() { GUILayout.Label("Pool size: " + Pool.CountInactive); if (GUILayout.Button("Create Particles")) { var amount = Random.Range(1, 10); for (int i = 0; i < amount; ++i) { var ps = Pool.Get(); ps.transform.position = Random.insideUnitSphere * 10; ps.Play(); } } } }

Declaration

public PooledObject<T> Get(out T v);

Parameters

v Out parameter that will contain a reference to an instance from the pool.

Returns

PooledObject<T> A PooledObject that will return the instance back to the pool when its Dispose method is called.

Description

Returns a PooledObject that will automatically return the instance to the pool when it is disposed.

using System.Text;
using UnityEngine;
using UnityEngine.Pool;

public class Example : MonoBehaviour { static ObjectPool<StringBuilder> stringBuilderPool = new ObjectPool<StringBuilder>( () => new StringBuilder(), (sb) => sb.Clear());

void Update() { StringBuilder stringBuilder;

// When the pooled object is disposed the string builder will be returned back to the pool using (stringBuilderPool.Get(out stringBuilder)) { stringBuilder.AppendLine("Some text"); Debug.Log(stringBuilder.ToString()); } } }