Picking a 2D Box Collider with the mouse in Unity

Question

I have a scene with a bunch of 2D doors that have 2d Box Colliders (no trigger) on them and that live on a Canvas. I would like to be able to click on them with the mouse, but have had no luck.

Following this earlier topic: (2D) Detect mouse click on object with no script attached , I did the following:

    if (Input.GetMouseButtonDown(0))
    {
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit2D hit = Physics2D.Raycast (ray.origin, ray.direction, Mathf.Infinity);
        if (hit)
        {
            Debug.Log(hit.collider.gameObject.name);
        }
    }

However, (hit) is always null. I have no RigidBody2D objects in my scene, because I only need mouse selection, not any interaction between objects.

In the inspector I the green box collider but clicking within it in the scene (not the inspector, obviously) runs the MouseButtonDown() code but still no Raycast hit.

What else could I be missing?

To reduce this to its simplest, you can do the following:

• Create a new 2D scene with a canvas
• Add two 100x100 Images to the Canvas
• Add a Boxcolllider2D to each image
• Now what script is required to detect mouse clicks within them?

Answer 1

You should create Buttons instead of Images if you are working in Canvas. There you can assign image and events.

Answer 2

I am not sure what is wrong with your script as it seems fine, are you sure you have setup your images properly? I have the following setup in my inspector with the following code and it works.

void Update()
{
    if (Input.GetMouseButtonDown(0))
    {
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit2D hit = Physics2D.Raycast(ray.origin, ray.direction, Mathf.Infinity);
        if (hit)
        {
            Debug.Log(hit.collider.gameObject.name);
        }
    }
}

Another solution is to put a component on each door and inherit from IPointerClick\Down\UpHandler

Like this:

using UnityEngine;
using UnityEngine.EventSystems;

public class DoorViewController : MonoBehaviour, IPointerClickHandler
{
    public void OnPointerClick(PointerEventData eventData)
    {
        Debug.Log("Clicked on: " + gameObject.name);
    }
}

For more advanced things you might want to look at:

IPointerInputModule - I would link but the rules of this site are very draconian.

Answer 3

If you are open to having a script on the game object using the built in method OnMouseDown() works great to detect when clicked or tapped.

void OnMouseDown()
{
    // do stuff
}