Problem With Unity Code

Unity Engine
,
1

Hi all, I am coding a pong game. The code below shows that it is supposed to respawn after waiting for 1 second, however after adding the yield return new Waitforseconds, for some reason it does not respawn! If I comment that line out, the ball respawns just fine. Does anyone know why?

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

public class OnScore : MonoBehaviour
{
    private int player1score;
    private int player2score;
    private Rigidbody2D rb;
    public BallMovement ballMovement;
    private void Start()
    {
        player1score = 0;
        player2score = 0;
        rb = GetComponent<Rigidbody2D>();
        ballMovement = GetComponent<BallMovement>();
    }
    private void OnCollisionEnter2D(Collision2D collision)
    {
        if (collision.gameObject.name == "WallLeft")
        {
            player1score += 1;
            Debug.Log("Player1:" + player1score);
            StartCoroutine(ResetBallPosition());
        }

        if (collision.gameObject.name == "WallRight")
        {
            player2score += 1;
            Debug.Log("Player2:" + player2score);
            StartCoroutine(ResetBallPosition());
        }
    }

    IEnumerator ResetBallPosition()
    {
        gameObject.SetActive(false);
        gameObject.transform.position = Vector3.zero;
        yield return new WaitForSeconds(1f); // the ball respawns at the centre if I delete this line, but after adding it it does not seem to work!
        gameObject.SetActive(true);
        rb.velocity = Vector2.right * ballMovement.speed;

        yield return null;
    }
}
2

I think it is because when you use WaitForSeconds, you need to have it being called for the entire time, like in Update or from a state machine. In your collision event, it occurs for a split second and will technically run the first 3 lines of the coroutine, but it wont reach a full second for the WaitForSeconds and will never execute the rest. I am not 100% but i have had issues with something similar to this as well.

My suggestion would be to change it away from a coroutine and make ResetBallPosition into 2 functions.
Have one to deactivate the gameobject and reset the position and then have another reactivate it and change the velocity. However, you need to call the 2nd function in the first one with an Invoke method.

void ResetBall()
{
    gameObject.SetActive(false);
    gameObject.transform.position = Vector3.zero;
    Invoke("ReactivateBall", 1f);
}

void ReactivateBall()
{
    gameObject.SetActive(true);
    rb.velocity = Vector2.right * ballMovement.speed;
}

Something like that should work. Then, in your collision event just call the ResetBall (or whatever you call it).