Creating top down 2D whip mechanic - unity3d

Question

What Whip should look like
I'm trying to create a whip that can extend in any direction the mouse is facing after pressing a certain button. If there are "grabbable" objects in the way such as an enemy or box, it should latch onto those objects and pull them around to collide with other objects for a certain amount of time.
I know that I need the different sprite shots of the whip extending and latching for animation, but I have no idea how to implement this in code and how to get the whip to stop short if it detects a "grabbable" object.

Answer 1

Attach this script to your player, this should get the job done:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Player : MonoBehaviour
{
public Transform player = null;
public float speed = 30f;
public string grabbableTag = "grabbable";
private LineRenderer line = null;
private float timer = 0f;
private bool grabbing = false;
private bool reached = false;
private Vector2 from = Vector2.zero;
private Vector2 to = Vector2.zero;
private Vector2 target = Vector2.zero;
private Transform grabbable = null;
private void Start()
{
player = transform;
line = new GameObject("Line").AddComponent<LineRenderer>();
line.startColor = Color.red;
line.endColor = Color.red;
// Assign a material
line.gameObject.SetActive(false);
reached = false;
grabbing = false;
}
private void Update()
{
if(grabbing)
{
Grabbing();
}
else
{
if (Input.GetMouseButtonDown(0))
{
Grab();
}
}
}
private void Grab()
{
Vector3 mousePosition = Input.mousePosition;
mousePosition.z = Vector3.Distance(player.position, Camera.main.transform.position);
to = Camera.main.ScreenToWorldPoint(mousePosition);
from = player.position;
Vector2 direction = (to - from).normalized;
float distance = Vector2.Distance(from, to);
RaycastHit2D[] hits = Physics2D.RaycastAll(from, direction, distance);
grabbable = null;
for (int i = 0; i < hits.Length; i++)
{
if (hits[i].transform.tag == grabbableTag)
{
grabbable = hits[i].transform;
break;
}
}
if (grabbable != null)
{
distance = Vector2.Distance(player.position, grabbable.position);
to = from + direction * distance;
}
grabbing = true;
reached = false;
target = from;
timer = 0;
line.gameObject.SetActive(true);
line.positionCount = 2;
line.SetPosition(0, from);
line.SetPosition(1, from);
}
private void Grabbing()
{
if (reached)
{
target = Vector2.Lerp(target, from, speed * Time.deltaTime);
if (target == from)
{
GrabDone(grabbable);
grabbing = false;
line.gameObject.SetActive(false);
}
}
else
{
target = Vector2.Lerp(target, to, speed * Time.deltaTime);
if(target == to)
{
reached = true;
}
}
line.SetPosition(1, target);
if (reached && grabbable != null)
{
grabbable.position = target;
}
}
private void GrabDone(Transform grabbed)
{
if(grabbed != null)
{
// Do somthing ...
Destroy(grabbed.gameObject);
}
}
}