koobas.hobune.stream
Getting a Raycast rope to follow its object
Hey all! So I have been working on a 2D game for a few months now. It is a platformer using a grappling hook to swing from object to object. As a basis I went with this: https://www.raywenderlich.com/348-make-a-2d-grappling-hook-game-in-unity-part-1 to get started. From then I have ironed out a bunch of bugs, etc. And it works great! But I have hit a blockade that I have no idea how to fix. And I was wondering if you wonderful people would be able to help. So I have a point where you attach to a moving grapple point to get through a level. But once the grapple hits, it does not follow the object as it is not really attached, it just takes the point of the raycast it hits. Is there a way to fix this as to possibly make it so the attached rope will follow the raycasted object? This one has me stumped so any help means the world! Thanks!
public class RopeSystem : MonoBehaviour
{
public LineRenderer ropeRenderer;
public LayerMask ropeLayerMask;
public float climbSpeed = 3f;
public GameObject ropeHingeAnchor;
public DistanceJoint2D ropeJoint;
public Transform crosshair;
public SpriteRenderer crosshairSprite;
public PlayerMovement playerMovement;
private bool ropeAttached;
private Vector2 playerPosition;
private List<Vector2> ropePositions = new List<Vector2>();
public float ropeMaxCastDistance = 10f;
private Rigidbody2D ropeHingeAnchorRb;
private bool distanceSet;
private bool isColliding;
private Dictionary<Vector2, int> wrapPointsLookup = new Dictionary<Vector2, int>();
private SpriteRenderer ropeHingeAnchorSprite;
private bool touchingBarrier;
void Awake ()
{
ropeJoint.enabled = false;
playerPosition = transform.position;
ropeHingeAnchorRb = ropeHingeAnchor.GetComponent<Rigidbody2D>();
ropeHingeAnchorSprite = ropeHingeAnchor.GetComponent<SpriteRenderer>();
}
/// <summary>
/// Figures out the closest Polygon collider vertex to a specified Raycast2D hit point in order to assist in 'rope wrapping'
/// </summary>
/// <param name="hit">The raycast2d hit</param>
/// <param name="polyCollider">the reference polygon collider 2D</param>
/// <returns></returns>
private Vector2 GetClosestColliderPointFromRaycastHit(RaycastHit2D hit, PolygonCollider2D polyCollider)
{
// Transform polygoncolliderpoints to world space (default is local)
var distanceDictionary = polyCollider.points.ToDictionary<Vector2, float, Vector2>(
position => Vector2.Distance(hit.point, polyCollider.transform.TransformPoint(position)),
position => polyCollider.transform.TransformPoint(position));
var orderedDictionary = distanceDictionary.OrderBy(e => e.Key);
return orderedDictionary.Any() ? orderedDictionary.First().Value : Vector2.zero;
}
// Update is called once per frame
void Update ()
{
var worldMousePosition = Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, 0f));
var facingDirection = worldMousePosition - transform.position;
var aimAngle = Mathf.Atan2(facingDirection.y, facingDirection.x);
if (aimAngle < 0f)
{
aimAngle = Mathf.PI * 2 + aimAngle;
}
var aimDirection = Quaternion.Euler(0, 0, aimAngle * Mathf.Rad2Deg) * Vector2.right;
playerPosition = transform.position;
if (!ropeAttached)
{
SetCrosshairPosition(aimAngle);
playerMovement.isSwinging = false;
}
else
{
playerMovement.isSwinging = true;
playerMovement.ropeHook = ropePositions.Last();
crosshairSprite.enabled = false;
// Wrap rope around points of colliders if there are raycast collisions between player position and their closest current wrap around collider / angle point.
if (ropePositions.Count > 0)
{
var lastRopePoint = ropePositions.Last();
var playerToCurrentNextHit = Physics2D.Raycast(playerPosition, (lastRopePoint - playerPosition).normalized, Vector2.Distance(playerPosition, lastRopePoint) - 0.1f, ropeLayerMask);
if (playerToCurrentNextHit)
{
var colliderWithVertices = playerToCurrentNextHit.collider as PolygonCollider2D;
if (colliderWithVertices != null)
{
var closestPointToHit = GetClosestColliderPointFromRaycastHit(playerToCurrentNextHit, colliderWithVertices);
if (wrapPointsLookup.ContainsKey(closestPointToHit))
{
// Reset the rope if it wraps around an 'already wrapped' position.
ResetRope();
return;
}
ropePositions.Add(closestPointToHit);
wrapPointsLookup.Add(closestPointToHit, 0);
distanceSet = false;
}
}
}
}
UpdateRopePositions();
HandleRopeLength();
HandleInput(aimDirection);
HandleRopeUnwrap();
}
/// <summary>
/// Handles input within the RopeSystem component
/// </summary>
/// <param name="aimDirection">The current direction for aiming based on mouse position</param>
private void HandleInput(Vector2 aimDirection)
{
if (Input.GetMouseButton(0))
{
if (ropeAttached) return;
ropeRenderer.enabled = true;
var hit = Physics2D.Raycast(playerPosition, aimDirection, ropeMaxCastDistance, ropeLayerMask);
if (hit.collider != null)
{
ropeAttached = true;
if (!ropePositions.Contains(hit.point) && hit.transform.gameObject.layer == 12)
{
ropeRenderer.enabled = false;
ropeAttached = false;
ropeJoint.enabled = false;
}
else if (!ropePositions.Contains(hit.point))
{
// Jump slightly to distance the player a little from the ground after grappling to something.
transform.GetComponent<Rigidbody2D>().AddForce(new Vector2(0f, 2f), ForceMode2D.Impulse);
ropePositions.Add(hit.point);
wrapPointsLookup.Add(hit.point, 0);
ropeJoint.distance = Vector2.Distance(playerPosition, hit.point);
ropeJoint.enabled = true;
ropeHingeAnchorSprite.enabled = true;
}
}
else
{
ropeRenderer.enabled = false;
ropeAttached = false;
ropeJoint.enabled = false;
}
}
if (Input.GetMouseButton(1))
{
ResetRope();
}
}
/// <summary>
/// Resets the rope in terms of gameplay, visual, and supporting variable values.
/// </summary>
private void ResetRope()
{
ropeJoint.enabled = false;
ropeAttached = false;
playerMovement.isSwinging = false;
ropeRenderer.positionCount = 2;
ropeRenderer.SetPosition(0, transform.position);
ropeRenderer.SetPosition(1, transform.position);
ropePositions.Clear();
wrapPointsLookup.Clear();
ropeHingeAnchorSprite.enabled = false;
}
/// <summary>
/// Move the aiming crosshair based on aim angle
/// </summary>
/// <param name="aimAngle">The mouse aiming angle</param>
private void SetCrosshairPosition(float aimAngle)
{
if (!crosshairSprite.enabled)
{
crosshairSprite.enabled = true;
}
}
/// <summary>
/// Retracts or extends the 'rope'
/// </summary>
private void HandleRopeLength()
{
if (Input.GetAxis("Vertical") >= 1f && ropeAttached && !isColliding)
{
ropeJoint.distance -= Time.deltaTime * climbSpeed;
}
else if (Input.GetAxis("Vertical") < 0f && ropeAttached && ropeJoint.distance <= ropeMaxCastDistance && touchingBarrier == false)
{
ropeJoint.distance += Time.deltaTime * climbSpeed;
}
}
/// <summary>
/// Handles updating of the rope hinge and anchor points based on objects the rope can wrap around. These must be PolygonCollider2D physics objects.
/// </summary>
private void UpdateRopePositions()
{
if (ropeAttached)
{
ropeRenderer.positionCount = ropePositions.Count + 1;
for (var i = ropeRenderer.positionCount - 1; i >= 0; i--)
{
if (i != ropeRenderer.positionCount - 1) // if not the Last point of line renderer
{
ropeRenderer.SetPosition(i, ropePositions[i]);
// Set the rope anchor to the 2nd to last rope position (where the current hinge/anchor should be) or if only 1 rope position then set that one to anchor point
if (i == ropePositions.Count - 1 || ropePositions.Count == 1)
{
if (ropePositions.Count == 1)
{
var ropePosition = ropePositions[ropePositions.Count - 1];
ropeHingeAnchorRb.transform.position = ropePosition;
if (!distanceSet)
{
ropeJoint.distance = Vector2.Distance(transform.position, ropePosition);
distanceSet = true;
}
}
else
{
var ropePosition = ropePositions[ropePositions.Count - 1];
ropeHingeAnchorRb.transform.position = ropePosition;
if (!distanceSet)
{
ropeJoint.distance = Vector2.Distance(transform.position, ropePosition);
distanceSet = true;
}
}
}
else if (i - 1 == ropePositions.IndexOf(ropePositions.Last()))
{
// if the line renderer position we're on is meant for the current anchor/hinge point...
var ropePosition = ropePositions.Last();
ropeHingeAnchorRb.transform.position = ropePosition;
if (!distanceSet)
{
ropeJoint.distance = Vector2.Distance(transform.position, ropePosition);
distanceSet = true;
}
}
}
else
{
// Player position
ropeRenderer.SetPosition(i, transform.position);
}
}
}
}
void OnTriggerStay2D(Collider2D colliderStay)
{
isColliding = true;
}
private void OnTriggerExit2D(Collider2D colliderOnExit)
{
isColliding = false;
}
private void OnCollisionEnter2D(Collision2D Barrier)
{
touchingBarrier = true;
Debug.Log("Touching");
}
private void OnCollisionExit2D(Collision2D Barrier)
{
touchingBarrier = false;
Debug.Log("Not Touching");
}
private void HandleRopeUnwrap()
{
if (ropePositions.Count <= 1)
{
return;
}
// Hinge = next point up from the player position
// Anchor = next point up from the Hinge
// Hinge Angle = Angle between anchor and hinge
// Player Angle = Angle between anchor and player
// 1
var anchorIndex = ropePositions.Count - 2;
// 2
var hingeIndex = ropePositions.Count - 1;
// 3
var anchorPosition = ropePositions[anchorIndex];
// 4
var hingePosition = ropePositions[hingeIndex];
// 5
var hingeDir = hingePosition - anchorPosition;
// 6
var hingeAngle = Vector2.Angle(anchorPosition, hingeDir);
// 7
var playerDir = playerPosition - anchorPosition;
// 8
var playerAngle = Vector2.Angle(anchorPosition, playerDir);
if (!wrapPointsLookup.ContainsKey(hingePosition))
{
Debug.LogError("We were not tracking hingePosition (" + hingePosition + ") in the look up dictionary.");
return;
}
if (playerAngle < hingeAngle)
{
// 1
if (wrapPointsLookup[hingePosition] == 1)
{
UnwrapRopePosition(anchorIndex, hingeIndex);
return;
}
// 2
wrapPointsLookup[hingePosition] = -1;
}
else
{
// 3
if (wrapPointsLookup[hingePosition] == -1)
{
UnwrapRopePosition(anchorIndex, hingeIndex);
return;
}
// 4
wrapPointsLookup[hingePosition] = 1;
}
}
private void UnwrapRopePosition(int anchorIndex, int hingeIndex)
{
// 1
var newAnchorPosition = ropePositions[anchorIndex];
wrapPointsLookup.Remove(ropePositions[hingeIndex]);
ropePositions.RemoveAt(hingeIndex);
// 2
ropeHingeAnchorRb.transform.position = newAnchorPosition;
distanceSet = false;
// Set new rope distance joint distance for anchor position if not yet set.
if (distanceSet)
{
return;
}
ropeJoint.distance = Vector2.Distance(transform.position, newAnchorPosition);
distanceSet = true;
}
}
