Unity 2D 两圆对撞机

Question

I am new to Unity and trying to write a 2D programm where I have multiple circles on a screen and make them change direction everytime they collide with another circle or a margin.

Here is the code I wrote for when a circle collides with a margin, in the Update method:

transform.Translate(direction * speed * Time.deltaTime);
if (transform.position.y < GameManager.bottomLeft.y + radius && direction.y < 0)
{
    direction.y = -direction.y;
}
if(transform.position.y > GameManager.topRight.y - radius && direction.y > 0)
{
    direction.y = -direction.y;
}
if(transform.position.x < GameManager.bottomLeft.x + radius && direction.x < 0)
{
    direction.x = -direction.x;
}
if(transform.position.x > GameManager.topRight.x - radius && direction.x > 0)
{
    direction.x = -direction.x;
}

direction is defined as new Vector2(Random.value, Random.value) in Start method. Now I read on the internet that if two circles meet, I can implement the behaviour in

private void OnTriggerEnter2D(Collider2D collision)
{
    if(collision.tag == "Ball")
    {
    }  
}

How can I write the code so that two circles change directions when colliding?

Answer 1

I'm not sure how you defined direction but this changes both objects direction upon a collision if the collider is tagged as Ball , however if you are trying to do something more like a mirrored movement you may want to change something with rotation.

private void OnTriggerEnter2D(Collider2D collision)
{
    if(collision.tag == "Ball")
    {
        GameObject CollidedObject = collision.gameObject;
        CollidedObject.direction.x = -CollidedObject.direction.x;
        CollidedObject.direction.y = -CollidedObject.direction.y;
        this.direction.x = -this.direction.x;
        this.direction.y = -this.direction.y;
    }  
}