OnCollisionEnter for only one object with same script-CodePudding

The problem is that - when two objects with the same scripts collide, I need to destroy them and create a new object. But they collide eachother and instead of one final object,i have 2 of them.

private void OnCollisionEnter2D(Collision2D collision)
{
    var drop = collision.gameObject.GetComponent<DropBase>();
    if (drop != null)
    {
        Destroy(collision.gameObject);
        Instantiate(_pile, transform.position, Quaternion.identity);
        Destroy(gameObject);
    }
}

I was trying give every of object lifetime,and the longer living object have rights to create new one,but i have situation where thay created at same time,and this method doesn't work.

CodePudding user response：

You can try to notify another object that the collision is already processed. It can be done in different ways, here is one of them:

public bool IsPileInstantiated { get; private set; } 

void Awake()
{
    IsPileInstantiated = false;
}

private void OnCollisionEnter2D(Collision2D collision)
{
    var drop = collision.gameObject.GetComponent<DropBase>();
    if (drop != null)
    {
        if(drop.IsPileInstantiated == false)
        {
            Instantiate(_pile, transform.position, Quaternion.identity);
            this.IsPileInstantiated = true;
        }
        Destroy(gameObject);
    }
}

Perhaps it even has the sense to move this logic out of your drop objects. For example, notify another object (some GameManager or something like that) about a collision, and that object will have events from both objects, can filter these events, destroy objects if needed and create a needed object if it is needed.

CodePudding user response：

You can deactive the two game objects before destroying them, then you can ignore the collision if one of the game object is inactive.

private void OnCollisionEnter2D(Collision2D collision)
{
    var incomingGameObject = collision.gameObject;
    if(!gameObject.activeSelf || !incomingGameObject.activeSelf)
        return;

    var drop = incomingGameObject.GetComponent<DropBase>();
    if (drop != null)
    {
        incomingGameObject.SetActive(false);
        Destroy(incomingGameObject);
        Instantiate(_pile, transform.position, Quaternion.identity);
        gameObject.SetActive(false);
        Destroy(gameObject);
    }
}