Physics2D.Raycast

Physics2DRaycast.cs

using UnityEngine;
using System.Collections;

public class Test : MonoBehaviour {

	public LayerMask targetLayer;
	
	Vector3 prevPos;

	void Start () {
	}
	
	void Update () 
	{
		// to mouse point
		Ray mousePos = Camera.main.ScreenPointToRay(Input.mousePosition);
		RaycastHit2D hit = Physics2D.Raycast(mousePos.origin, mousePos.direction,Mathf.Infinity, targetLayer);
		if (hit.collider != null) 
		{
			Destroy(hit.transform.gameObject);
		}
		
		// from point to point
		Vector3 mousePos = Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x,Input.mousePosition.y,10));
		hit = Physics2D.Linecast(prevPos, mousePos);
		if (hit.collider != null) 
		{
			Debug.Log("collided at:"+hit.point);
		}
		prevPos = mousePos;
	}
}