Cannot implicitly convert type `UnityEngine.Vector2' to `UnityEngine.Ray2D'

Question

I am new with Unity and I need rays to work in 2d, so I am trying to use Ray2D, but I got this weird error:

 Cannot implicitly convert type `UnityEngine.Vector2' to `UnityEngine.Ray2D'

Here is the code line which causes error:

 Ray2D ray = new Vector2 (Camera.main.ScreenToWorldPoint(Input.mousePosition).x, Camera.main.ScreenToWorldPoint(Input.mousePosition).y);

And here is whole function that causes error:

 void touching2D (Vector3 touchPosition, int touchNumber)
     {
 
         Ray2D ray = new Vector2 (Camera.main.ScreenToWorldPoint(Input.mousePosition).x, Camera.main.ScreenToWorldPoint(Input.mousePosition).y);
         RaycastHit hit = new RaycastHit();
         
         if(Physics2D.Raycast(ray, out hit,130))
         {
             hit.collider.SendMessage("pressed");
             touchedSomething = "Yes!";
         }
     }

Answer 1

Answer by robertbu · Jan 10, 2014 at 03:52 PM

A Vector2 is a direction. A Ray is a position (origin) and a direction. It looks to me like you want to cast a ray from the current position of the object this script is attached to in the direction of the mouse cursor. Assuming an orthographic camera, this should work to construct your ray:

 Vector2 v = Camera.main.ScreenToWorldPoint(Input.mousePosition) - transform.position;
 Ray2D ray = new Ray(transform.position, v);

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Norax · Aug 04, 2014 at 11:20 AM 0

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Looks like that solution doesn't work anymore. You need the variable v to be a Vector3. So I guess this should be the fix:

 Vector3 v = Camera.main.ScreenToWorldPoint(Input.mousePosition) - transform.position;
 Ray2D ray = new Ray(transform.position, v);

What I dont really get is, why do you substract transform.position?

robertbu · Aug 04, 2014 at 01:58 PM 0

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You subtract 'transform.position' to create a vector that has the direction from your objects position towards the mouse position. If you did not subtract transform.position, v would be from the origin. If your character is fixed at the origin, then you would not need to subtract transform.position.

Norax · Aug 04, 2014 at 02:16 PM 0

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Oh, got it. Thanks :)

By the way, shouldn't be the constructor Ray2D? Like this:

 Vector3 v = Camera.main.ScreenToWorldPoint(Input.mousePosition) - transform.position;
 Ray2D ray = new Ray2D(new Vector2(transform.position.x,transform.position.y),new Vector2(v.x,v.y));

Cannot implicitly convert type `UnityEngine.Vector2' to `UnityEngine.Ray2D'

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