GameObjectPool

GameObjectPool.cs

#region [Copyright (c) 2015 Cristian Alexandru Geambasu]
//	Distributed under the terms of an MIT-style license:
//
//	The MIT License
//
//	Copyright (c) 2015 Cristian Alexandru Geambasu
//
//	Permission is hereby granted, free of charge, to any person obtaining a copy of this software 
//	and associated documentation files (the "Software"), to deal in the Software without restriction, 
//	including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, 
//	and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, 
//	subject to the following conditions:
//
//	The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
//
//	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
//	INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR 
//	PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE 
//	FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
//	ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#endregion
using UnityEngine;
using System.Collections.Generic;

namespace TeamUtility
{
	public class GameObjectPool : System.IDisposable
	{
		private const string ON_POOLED_INSTANCE_RESET = "OnPooledInstanceReset";
		private const string ON_POOLED_INSTANCE_INITIALIZE = "OnPooledInstanceInitialize";

		private Queue<GameObject> m_freeInstances;
		private HashSet<GameObject> m_activeInstances;
		private GameObject m_prefab;
		private int m_maxCapacity;
		private int m_currentCapacity;
		private bool m_isDisposed;

		public int Alive { get { return m_activeInstances.Count; } }

		public GameObjectPool(GameObject prefab, int maxCapacity = 100)
		{
			m_prefab = prefab;
			m_freeInstances = new Queue<GameObject>();
			m_activeInstances = new HashSet<GameObject>();
			m_maxCapacity = maxCapacity;
			m_currentCapacity = 0;
			m_isDisposed = false;
		}

		public GameObject Create()
		{
			if(m_isDisposed)
				return null;

			GameObject instance = null;
			if(m_freeInstances.Count > 0)
			{
				instance = m_freeInstances.Dequeue();
				instance.SetActive(true);
				instance.SendMessage(ON_POOLED_INSTANCE_INITIALIZE, SendMessageOptions.RequireReceiver);
			}
			else
			{
				if(m_currentCapacity < m_maxCapacity)
				{
					instance = GameObject.Instantiate<GameObject>(m_prefab);
					if(instance != null)
						instance.SendMessage(ON_POOLED_INSTANCE_INITIALIZE, SendMessageOptions.RequireReceiver);
					m_currentCapacity++;
				}
			}

			if(instance != null)
				m_activeInstances.Add(instance);

			return instance;
		}

		public void Free(GameObject gameObject)
		{
			if(m_isDisposed)
				return;

			if(m_activeInstances.Contains(gameObject))
			{
				gameObject.SendMessage(ON_POOLED_INSTANCE_RESET, SendMessageOptions.RequireReceiver);
				gameObject.SetActive(false);
				m_freeInstances.Enqueue(gameObject);
				m_activeInstances.Remove(gameObject);
			}
		}

		public void FreeAll()
		{
			if(m_isDisposed)
				return;

			foreach(var gameObject in m_activeInstances)
			{
				if(gameObject != null)
				{
					gameObject.SendMessage(ON_POOLED_INSTANCE_RESET, SendMessageOptions.RequireReceiver);
					gameObject.SetActive(false);
					m_freeInstances.Enqueue(gameObject);
				}
			}
			m_activeInstances.Clear();
		}

		public void Dispose()
		{
			if(!m_isDisposed)
			{
				FreeAll();
				while(m_freeInstances.Count > 0)
				{
					GameObject gameObject = m_freeInstances.Dequeue();
					GameObject.Destroy(gameObject);
				}
				m_isDisposed = true;
			}
		}
	}
}