Stuck figuring out how to push a GameObject using mouse position angle

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1

Hi everybody, I’m fairly new to Unity and stuck trying to figure out some practice gameplay I’d like to script.

The gameplay is very simple. If I tap (or click) on an angle relative to the main character, he will bounce in the opposite direction. The player doesn’t necessarily have to touch the circle, I just want to consider the angle of the tap/click.

I made a few ugly drawings to explain better, hopefully they make sense:

And of course the same goes in every angle:

I’ve learned how to make a GameObject move towards the area I click:

    Vector3 dir = Input.mousePosition - newPosition;
    float angle = Mathf.Atan2 (dir.y, dir.x) * Mathf.Rad2Deg;

But I guess what i’m looking for is the inverse of this, and I can’t figure out how to do it :frowning: It’s a 2D game I and was thinking of using the RigidBody2D in order to use force. Thanks in advance!

2

Well it’s easy enough to invert the angle (just stick a “-” before Mathf.Atan2, or alternatively, swap tho order of the subtraction in line 2).

However you don’t actually need the angle to do what you’re wanting. You want to apply a force to the player, and a force is defined in terms of X and Y. You already have those in “dir” as of line 2. (Though what you have there is a vector that points towards the mouse position; you probably want to swap that subtraction, so it points away from the mouse, towards the player, instead.)

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3

Thank you very much Joe, that definitely did it. Also added drag so the GameObject slows down. I’m doing all this in the Update method though, perhaps since it’s a RigidBody, I should update in FixedUpdate.

Thanks again Joe.

        Vector3 dir = Vector3.zero;

        if (Input.GetMouseButton (0)) {
            rigidBody.AddForce (Vector2.zero);
            rigidBody.velocity = Vector2.zero;

            dir = Input.mousePosition - newPosition;
            float angle = Mathf.Atan2 (-dir.y, -dir.x) * Mathf.Rad2Deg;

            transform.rotation = Quaternion.AngleAxis (angle, Vector3.forward);        
        }
            
        dir.Normalize ();
      
        rigidBody.AddForce (-dir * 40.0f, ForceMode2D.Impulse);
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