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How to set Object pooling correctly in 2D game?

I have a couple of problems with object pooling in Unity with my 2D game, cannon balls don't want to stop when there is a collision with the wall, and 1 of them bursts shoot and the other 9 shoot together connected with each other, my cannon is static object on scene. Can someone help or give me some hint about it.
Here is my code, 3 scripts:
ObjectPooling.cs
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class ObjectPooling : MonoBehaviour
{
public static ObjectPooling instance;
[SerializeField] public GameObject objectToPool;
private List<GameObject> cannonBalls = new List<GameObject>();
private int numberOfObjects = 20;
private void Awake()
{
instance = this;
}
// Start is called before the first frame update
void Start()
{
for (int i = 0; i < numberOfObjects; i++)
{
GameObject gameObject = Instantiate(objectToPool);
gameObject.SetActive(false);
cannonBalls.Add(gameObject);
}
}
// Update is called once per frame
void Update()
{
}
public GameObject GetCannonBallObject()
{
for (int i = 0; i < cannonBalls.Count; i++)
{
if (!cannonBalls[i].activeInHierarchy)
{
return cannonBalls[i];
}
}
return null;
}
}
Cannon.cs
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Cannon : MonoBehaviour
{
[SerializeField] private Rigidbody2D rb;
[SerializeField] private GameObject cannonBall;
[SerializeField] private Transform cannonBallPosition;
void Start()
{
}
private void Update()
{
Fire();
}
private void Fire()
{
cannonBall = ObjectPooling.instance.GetCannonBallObject();
if(cannonBall != null)
{
cannonBall.transform.position = cannonBallPosition.position;
cannonBall.SetActive(true);
}
}
}
CannonBall.cs
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class CannonBall : MonoBehaviour
{
private float speed = 10f;
[SerializeField] private Rigidbody2D rb;
// Start is called before the first frame update
void Start()
{
}
// Update is called once per frame
void Update()
{
rb.velocity = Vector2.left * speed;
}
private void OnCollisionEnter2D(Collision2D collision)
{
if (collision.gameObject.CompareTag("FloorAndWall"))
{
// Destroy(this.gameObject);
gameObject.SetActive(false);
}
}
}

Why is you cannonball static? Have your tried not having it marked as static? Also, this problem has nothing to do with object pooling. Make sure that when your objects are enabled, all the components are active. Finally, when working with rigidbodies, you should handle them inside FixedUpdate(), and not inside Update().

Why does my enemy one hit me when I have 3 lives

I am in the process of making a game in Unity and I have run into a problem. I created a heart system UI + script and and enemy + script. In my game, I have 3 lives but when I made the enemy attack me, he one hits me. Is there a way that I can have a delay between each attack.
Here are the scripts.
Enemy Script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Enemy : MonoBehaviour
{
public Transform attackPoint;
public float attackrange = 0.5f;
public LayerMask playerlayers;
public float speed = 3f;
private Transform target;
IEnumerator Cooldown()
{
yield return new WaitForSeconds(3);
}
private void Update()
{
if (target != null)
{
float step = speed * Time.deltaTime;
transform.position = Vector2.MoveTowards(transform.position, target.position, step);
Collider2D[] hitplayers = Physics2D.OverlapCircleAll(attackPoint.position, attackrange, playerlayers);
foreach (Collider2D player in hitplayers)
{
player.GetComponent<HeartSystem>().TakeDamage(1);
StartCoroutine(Cooldown());
}
}
}
private void OnTriggerEnter2D(Collider2D other)
{
if (other.gameObject.tag == "Player")
{
target = other.transform;
}
}
private void OnTriggerExit2D(Collider2D other)
{
if (other.gameObject.tag == "Player")
{
target = null;
}
}
void OnDrawGizmosSelected()
{
if (attackPoint == null)
return;
Gizmos.DrawWireSphere(attackPoint.position, attackrange);
}
}
And here is my health system script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;
public class HeartSystem : MonoBehaviour
{
public GameObject[] hearts;
public int life;
void Update()
{
if (life < 1)
{
Destroy(hearts[0].gameObject);
SceneManager.LoadScene(SceneManager.GetActiveScene().buildIndex + 1);
}
else if (life < 2)
{
Destroy(hearts[1].gameObject);
}
else if (life < 3)
{
Destroy(hearts[2].gameObject);
}
}
public void TakeDamage(int d)
{
life -= d;
}
}
I hope we can find a solution.

So from what i understood from your code: the enemy targets the player on collision and once the player is targeted it receives damage on update.
The problem may be caused by the fact that the update method runs more than once until the collision ends. That would mean that your cooldown is not working.
I don't understand the way your timer works but I can tell you how i usually do.
Let's say the cooldown is 1sec. After attacking the player the first time you get the current time, add 1 second to it and store it like "nextAttackTime". Next time the enemy tries to attack it will check if the current time is equal or higher to the "nextAttackTime".
Your way of doing the cooldown looks very elegant but if it really isn't working you can consider trying it the way i described. it may not be as elegant but it is reliable.
-----EDIT-----
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Enemy : MonoBehaviour
{
public Transform attackPoint;
public float attackrange = 0.5f;
public LayerMask playerlayers;
public float speed = 3f;
private Transform target;
//First we will need a variable to store the time when the next attack will be possible, it starts with 0. We'll also create a public variable to define the cooldown duration
private float nextAttackTime = 0f;
public float attackCoolDown = 3f;
IEnumerator Cooldown()
{
yield return new WaitForSeconds(3);
}
private void Update()
{
if (target != null)
{
float step = speed * Time.deltaTime;
transform.position = Vector2.MoveTowards(transform.position, target.position, step);
Collider2D[] hitplayers = Physics2D.OverlapCircleAll(attackPoint.position, attackrange, playerlayers);
foreach (Collider2D player in hitplayers)
{
//then before dealing the damage we check if it is already time to attack again
if(Time.time >= nextAttackTime){
player.GetComponent<HeartSystem>().TakeDamage(1);
//After dealing damage we reset the time for the next attack. The Time.time should return the time in seconds that the game has been running and we'll add 3 seconds to that to define the time for the next attack.
nextAttackTime = (Time.time + attackCoolDown);
//StartCoroutine(Cooldown());
}
}
}
}
So this is the editted code with the changes I suggested. I edited it right here in StackOverflow with no help of a code editor so there could be some typos.

The Spawned enemy only moves, but not shoots in unity

I am new to unity. Recently, I have started making a survival fps game, there, I have 1 enemy, when I kill him, it will spawn more enemies. However, the spawned only move, but not shoot. Although, I have attached a script to it. here are all my code.
prefab_shooting-
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class prefab_shooting : MonoBehaviour
{
public float damage = 1f;
public float range = 100f;
public GameObject player;
public GameObject enemy;
private void Start()
{
player = GameObject.FindWithTag("Player");
enemy = GameObject.FindWithTag("PBR");
}
private void Update()
{
if (Vector3.Distance(transform.position, player.transform.position) < 25.0f)
{
Debug.Log(damage);
}
}
void Shoot()
{
RaycastHit hit;
if (Physics.Raycast(enemy.transform.position, enemy.transform.forward, out hit, range))
{
if (hit.transform.tag == "Player")
{
swat_death swat = hit.transform.GetComponent<swat_death>();
// Debug.Log(damage);
}
}
}
}
PBR_shooting (the enemy shooting)-
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PBR_shooting : MonoBehaviour
{
public float damage = 1f;
public float range = 100f;
public GameObject player;
public GameObject enemy;
private void Start()
{
player = GameObject.FindWithTag("Player");
enemy = GameObject.FindWithTag("PBR");
}
private void Update()
{
if (Vector3.Distance(transform.position, player.transform.position) < 25.0f)
{
Shoot();
}
}
void Shoot()
{
RaycastHit hit;
if(Physics.Raycast(enemy.transform.position, enemy.transform.forward, out hit, range))
{
if(hit.transform.tag == "Player")
{
swat_death swat = hit.transform.GetComponent<swat_death>();
// Debug.Log(swat.health);
swat.TakeDamage(damage);
}
}
}
Swat_death (player_death) -
using UnityEngine;
using UnityEngine.SceneManagement;
public class swat_death : MonoBehaviour
{
static float health = 250f;
public GameObject player;
public void TakeDamage(float amount)
{
health -= amount;
Debug.Log(health);
if (health <= 0f)
{
Debug.Log("STOP");
SceneManager.LoadScene("death_scene");
}
}
void Die()
{
}
private void OnCollisionEnter(Collision collision)
{
if(collision.transform.tag == "enemy_bullet")
{
//SceneManager.LoadScene("death_scene");
}
}
}
And the PBR_Death (from where the spawning starts) -
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PBR_death : MonoBehaviour
{
public GameObject player;
Animator anim;
public int XPos;
public int ZPos;
public GameObject TheEnemy;
public int enemyCount = 0;
public int points = 1;
public GameObject enemyGameObject;
void Start()
{
anim = GetComponent<Animator>();
enemyGameObject = GameObject.FindWithTag("PBR");
}
// Update is called once per frame
void OnCollisionEnter(Collision collision)
{
if (collision.transform.tag == "bullet")
{
anim.SetTrigger("isDying");
enemy_movement enemy = GetComponent<enemy_movement>();
enemy.enabled = false;
PBR_shooting shoot = GetComponent<PBR_shooting>();
shoot.enabled = false;
scoreManager.score += points;
GameObject go = Instantiate(enemyGameObject, new Vector3(Random.Range(34, 0), Random.Range(34, 0), 0), Quaternion.identity) as GameObject;
go.AddComponent<prefab_movement>();
go.AddComponent<prefab_death>();
go.AddComponent<prefab_shooting>();
// StartCoroutine(EnemySpawner());
Destroy(collision.gameObject);
}
}
Pls help me, I am stuck in this for almost 3 days..

You didn't call the function
In your first script (prefab_shooting-) You didn't call the Shoot() function.

Having problems with "OnCollisionEnter2D" in Unity2D

I'm using this code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;
public class CollisionPlayer : MonoBehaviour
{
public bool alreadyDied = false;
public GameObject player;
public float timeDeath;
public ParticleSystem particles;
public GameObject explosionGO;
private SpriteRenderer sr;
private BoxCollider2D bc;
private PlayerController walkScript;
void Start()
{
sr = GetComponent<SpriteRenderer>();
bc = GetComponent<BoxCollider2D>();
walkScript = GetComponent<PlayerController>();
}
void OnCollisionEnter2D (Collision2D collide)
{
if (collide.gameObject.CompareTag("Dead"))
{
Instantiate(particles, player.transform.position, Quaternion.identity);
Instantiate(explosionGO, player.transform.position, Quaternion.identity);
CinemachineShake.Instance.ShakeCamera(30f, .1f);
alreadyDied = true;
}
}
void Update()
{
if(alreadyDied == true)
{
timeDeath -= Time.deltaTime;
sr.enabled = false;
bc.enabled = false;
walkScript.enabled = false;
}
if(timeDeath <= 0)
{
SceneManager.LoadScene(SceneManager.GetActiveScene().buildIndex);
}
}
}
This is the bullet's code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class LeftBulletScript : MonoBehaviour
{
// Start is called before the first frame update
public float speed;
public float destructionLeftTime;
public ParticleSystem particles;
private GameObject thisGameObject;
void Start()
{
thisGameObject = this.gameObject;
Destroy(gameObject, destructionLeftTime);
}
void Update()
{
transform.Translate(Vector2.left * speed * Time.deltaTime);
if(destructionLeftTime > 0.05f)
{
destructionLeftTime -= Time.deltaTime;
}
else
{
Instantiate(particles, thisGameObject.transform.position, Quaternion.identity);
}
}
}
This code should spawn some particles and a sound effect when the player gets hit by something with tag "Dead". But that does not happen. I have a box collider 2D on both the bullet (that should kill me) and the player. My Rigidbody2D is dynamic on the player with z freezed. The bullet does not have a rigidbody. I made sure that the bullet actually has the tag "Dead", spelled the exact same way as the way I wrote on the script. The weirdest thing is that I used this code on another game and nothing changed (just the name of a script). Both the player and the bullet are on the same layer. Anyone could tell me what could have happened?

null reference exception when accessing the variable from a prefab

I get the null reference exception error when trying to change the boolean to right (or left in that regard). My prefab should spawn at FirepointL.
My script does recognise the prefeb as it does not return a Null for finding the prefab (tested this).
I made sure my boolean was set to Public and i had dropped all the GameObjects to their designated places in the Inspector.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerMovement : MonoBehaviour
{
public GameObject bullet;
private Rigidbody2D myRigidbody;
private float speed = 15;
private bool facingRight;
private bool ground = false;
private float jump = 23;
// Start is called before the first frame update
void Start()
{
facingRight = true;
myRigidbody = GetComponent<Rigidbody2D>();
}
// Update is called once per frame
void FixedUpdate()
{
float horizontal = Input.GetAxis("Horizontal");
bullet = GameObject.FindGameObjectWithTag("Button");
Movement(horizontal);
Flip(horizontal);
if (Input.GetKey("w"))
{
if (ground)
{
GetComponent<Rigidbody2D>().velocity = new Vector2(GetComponent<Rigidbody2D>().velocity.x, jump);
}
}
// this is the part that returns the error
if (facingRight == true)
{
bullet.GetComponent<weapon>().right = true;
}
if (facingRight == false)
{
bullet.GetComponent<weapon>().right = false;
}
}
void OnTriggerEnter2D()
{
ground = true;
}
void OnTriggerExit2D()
{
ground = false;
}
private void Movement(float horizontal)
{
myRigidbody.velocity = new Vector2(horizontal * speed,myRigidbody.velocity.y);
}
private void Flip(float horizontal)
{
if (horizontal > 0 && !facingRight || horizontal < 0 && facingRight)
{
facingRight = !facingRight;
Vector3 theScale = transform.localScale;
theScale.x *= -1;
transform.localScale = theScale;
}
}
}
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class weapon : MonoBehaviour
{
// Start is called before the first frame update
public bool right;
public Transform firepointR;
public Transform firepointL;
public GameObject bulletPrefab;
// Update is called once per frame
void Update()
{
if (Input.GetKeyDown("space"))
{
Debug.Log("It's the space key");
Shoot();
}
}
void Shoot()
{
if (right == true)
{
Instantiate(bulletPrefab, firepointR.position, firepointR.rotation);
}
if(right == false)
{
Instantiate(bulletPrefab, firepointL.position, firepointL.rotation);
}
}
}
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class bullet : MonoBehaviour
{
public float speed = 20;
public Rigidbody2D rb;
// Start is called before the first frame update
void Start()
{
rb.velocity = transform.right * speed;
}
// Update is called once per frame
void Update()
{
}
}

Not sure if it's the exact issue, but there's a problem in PlayerMovement class. When you retrieve bullet you assume that an object with Button tag is present.
In my opinion, you should check for it with
// this is the part that returns the error
if (bullet && facingRight == true)
{
bullet.GetComponent<weapon>().right = true;
}
if (bullet && facingRight == false)
{
bullet.GetComponent<weapon>().right = false;
}

I think there is a problem with naming conventions. You are trying to find out a bullet whose name is "Button" but when you are instantiating the gameobject, it names it to something like Button(clone).
One solution that comes in my mind:
1st step:
Make a public static variable inside PlayerMovement script.
public static PlayerMovement Instance;
private void Awake()
{
Instance = this;
}
Set its value inside the awake function so that you can call it from anywhere.
2nd step:
I modified the shoot function.
void Shoot()
{
GameObject _firePosition = right == true ? firepointR : firepointL;
PlayerMovement.Instance.bullet = Instantiate(bulletPrefab, _firePosition.position, _firePosition.rotation); // we are setting the reference on runtime whenever we spawn a new bullet.
}
3rd Step:
Remove this line from PlayerMovement script as it is not needed now.
bullet = GameObject.FindGameObjectWithTag("Button");
PS: Code will not work if you don't follow step 3. Let me know if it helps. :)