grapplinghook.cs

using UnityEngine;

//makes sure object has this componentes
[RequireComponent(typeof(Rigidbody2D),typeof(SpringJoint2D),typeof(LineRenderer))]
public class grapplinghook : MonoBehaviour {

	SpringJoint2D joint;
	LineRenderer lr;

	[SerializeField]
	float step = .1f;


	//tells whether or not rope is active
	bool state=false;


	Vector3 anchorPos;

	void Start () {

		//Sets Conponents and their parameters
		lr = GetComponent<LineRenderer> ();
		lr.numPositions=2;
		lr.startWidth = .1f;
		lr.endWidth = .1f;

		joint = GetComponent<SpringJoint2D> ();
		joint.frequency = 1000000;
	}
	
	// Update is called once per frame
	void Update () {

		//Create Rope
		if (Input.GetMouseButtonDown (0)) {
			Grapple (true);

		}
	else if (Input.GetMouseButtonUp(0))
		{
			//Delete Rope
			Grapple(false);

		}
	

		//If E is pressed rope shrinks
		if (Input.GetKey (KeyCode.E)) {
			joint.distance -= step;
		}
		else if (Input.GetKeyUp (KeyCode.E)) {

			//delete rope
			Grapple (false);

			}


		//if rope is active, it updates rope position
		if (state) {

			lr.SetPosition (0, transform.position);
			lr.SetPosition (1, anchorPos);

		}

	}
		
	void Grapple(bool state)
	{
		
		//enables/disables components
		joint.enabled = state;
		lr.enabled = state;


		//if rope is active sets its anchor point
		if (state==true) {
			
			anchorPos = Input.mousePosition;
			anchorPos.z = 10;
			anchorPos = Camera.main.ScreenToWorldPoint (anchorPos);

			joint.connectedAnchor = anchorPos;

		}
	}
}