简单的对象池分三步走:

• 建立对象池
• 拿到对象
• 回收对象

Test为对象池,Obj为自动回收的物体

Test.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Test : MonoBehaviour {
    //要复制的对象
    public GameObject mCube;
    //静态
    public static Test instance; 
    //存储复制体,利用栈先进后出的机制
    private Stack<GameObject> mStack = new Stack<GameObject>(); 
    //初始化
    private void Init(int count)
    {
        print("Init");
        for (int i = 0; i < count; i++)
        {
            GameObject obj = Instantiate(mCube);
            obj.gameObject.SetActive(false);
            mStack.Push(obj);
        }
        print("GameObject"+mStack.Count);
    }
    //拿物体
    public GameObject GetObj(Vector3 pos ,Quaternion rot)
    {
        print("get");
        if(mStack.Count < 2)
        {
            Init(10);
        }
        GameObject g = mStack.Pop();
        g.gameObject.SetActive(true);
        g.transform.position = pos;
        g.transform.rotation = rot;
        return g;
    }
    //回收物体
    public void Recycle(GameObject obj)
    {
        obj.gameObject.SetActive(false);
        mStack.Push(obj);
    }

    void Start() {
        instance = this;
        Init(15);
    }

    void Update()
    {
        if (Input.GetKeyDown(KeyCode.Space))
        {
            print("Space");
            Test.instance.GetObj(this.transform.position, Quaternion.identity);
        }
    }
}

Obj.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Obj : MonoBehaviour {
    private float mTime = 3f;

    void Update () {
        this.transform.position += Vector3.forward;
        
        if (mTime > 0)
        {
            mTime -= Time.deltaTime;
            if (mTime < 0)
            {
                Test.instance.Recycle(this.gameObject);
                mTime = 3f;
            }
        }
    }
}