[SOLVED] How to Launch An Object?

Unity Engine
1

I’m trying to make an object that you drag back, then launch it upon release, like a slingshot, but also have a linecast that shows the pullback line. I’ve looked at the Unity live training session here (starts at about 35:15) and am trying to do it that way, but it’s not launching the ball AND no line is being rendered.

My code:

using UnityEngine;
using System.Collections;

public class ballControl : MonoBehaviour
{
    public float maxStretch = 2f;
    public LineRenderer catapultLineFront;
    public LineRenderer catapultLineBack;

    private SpringJoint2D spring;
    private Transform catapult;
    private Ray rayToMouse;
    private Ray leftCatapultToProjectile;
    private float maxStretchSqr;
    private float circleRadius;
    private bool clickedOn;
    private Vector2 preVelocity;
    private Rigidbody2D rigidBody;
    private CircleCollider2D circle;

    void Awake ()
    {
        spring = GetComponent<SpringJoint2D> ();
        rigidBody = GetComponent<Rigidbody2D> ();
        circle = GetComponent<CircleCollider2D> ();

        catapult = spring.connectedBody.transform;
    }

    void Start ()
    {
        LineRendererSetup ();
       
        rayToMouse = new Ray (catapult.position, Vector3.zero);
        leftCatapultToProjectile = new Ray (catapultLineFront.transform.position, Vector3.zero);
        maxStretchSqr = maxStretch * maxStretch;
        circleRadius = circle.radius;
    }
   
    void Update ()
    {
        if (clickedOn)
        {
            Dragging ();
       
            if (spring != null)
            {
                if (!rigidBody.isKinematic && preVelocity.sqrMagnitude > rigidBody.velocity.sqrMagnitude)
                {
                    Destroy (spring);
                    rigidBody.velocity = preVelocity;
                }
            }
        }
       
        if (!clickedOn)
        {   
            preVelocity = rigidBody.velocity;
            LineRendererUpdate ();
        }
        else
        {
            catapultLineFront.enabled = false;
            catapultLineBack.enabled = false;
        }
    }

    void LineRendererSetup ()
    {
        catapultLineFront.SetPosition (0, catapultLineFront.transform.position);
        catapultLineBack.SetPosition (0, catapultLineBack.transform.position);

        catapultLineFront.sortingLayerName="Foreground";
        catapultLineBack.sortingLayerName="Foreground";

        catapultLineFront.sortingOrder = 3;
        catapultLineBack.sortingOrder = 1;
    }

    void OnMouseDown ()
    {
        spring.enabled = false;
        clickedOn = true;
    }

    void OnMouseUp ()
    {
        spring.enabled = true;
        rigidBody.isKinematic = false;
        clickedOn = false;

    }

    void Dragging ()
    {
        Vector3 mouseWorldPoint = Camera.main.ScreenToWorldPoint (Input.mousePosition);
        Vector2 catapultToMouse = mouseWorldPoint - catapult.position;
       
        if (catapultToMouse.sqrMagnitude > maxStretchSqr)
        {
            rayToMouse.direction = catapultToMouse;
            mouseWorldPoint = rayToMouse.GetPoint (maxStretch);
        }

        mouseWorldPoint.z = 0f;
        transform.position = mouseWorldPoint;
    }

    void LineRendererUpdate ()
    {
        Vector2 catapultToProjectile = transform.position - catapultLineFront.transform.position;

        leftCatapultToProjectile.direction = catapultToProjectile;

        Vector3 holdPoint=leftCatapultToProjectile.GetPoint(catapultToProjectile.magnitude+circleRadius);

        catapultLineFront.SetPosition (1, holdPoint);
        catapultLineBack.SetPosition (1, holdPoint);
    }
}

Any help would be greatly appreciated!

– Chris

2

I can’t continue the game until I have this figured out so this is really frustrating!