Seminar_Cable_Joints_Unity/Assets/RollerProperties.cs

using TMPro;
using UnityEngine;
using UnityEngine.Serialization;

[System.Serializable]
public class RollerProperties : MonoBehaviour {
    //settings
    [SerializeField] public bool start = false;
    [SerializeField] public bool clockwise = false;
    [SerializeField] public GameObject linkTo = null;
    [SerializeField] public RotationType movement = RotationType.Fixed;
    [FormerlySerializedAs("fixedAttachmentPoint")] [SerializeField] public bool useFixedAttachmentPoint = false;
    [SerializeField] public Vector2 attachmentPoint = new Vector2(0, 0);

    //references
    protected internal GameObject text;
    protected internal DistanceJoint2D distanceJoint2D = null;

    //simulation properties
    protected internal float actualDistance;

    public (float?, float?) updateDistanceJoints() {
        Vector2? left = null, right = null;

        if (linkTo != null) {
            if (useFixedAttachmentPoint && !linkTo.GetComponent<RollerProperties>().useFixedAttachmentPoint) {
                //left = attachmentPoint;
                right = CableJointsAlgorithm.TangentPointCircle(gameObject, linkTo);
            }
            else if (!useFixedAttachmentPoint && linkTo.GetComponent<RollerProperties>().useFixedAttachmentPoint) {
                left = CableJointsAlgorithm.TangentPointCircle(linkTo,gameObject);
                //right = linkTo.GetComponent<RollerProperties>().attachmentPoint;
            }
            else if (!useFixedAttachmentPoint && !linkTo.GetComponent<RollerProperties>().useFixedAttachmentPoint) {
                (left, right) = CableJointsAlgorithm.TangentCircleCircle(gameObject, linkTo);
            }
            /*
            else {
                left = attachmentPoint;
                right = linkTo.GetComponent<RollerProperties>().attachmentPoint;
            }*/
        }

        
        //TODO: assumes circles are flat for sufficiently small timesteps
        float? leftSurfaceDist = null, rightSurfaceDist = null;
        if (left.HasValue) {
            
            leftSurfaceDist = CableJointsAlgorithm.CirclePointDistance(gameObject.transform.TransformPoint(distanceJoint2D.anchor), gameObject.transform.TransformPoint(left.Value), gameObject);

            // leftSurfaceDist = (gameObject.transform.TransformPoint(distanceJoint2D.anchor) - gameObject.transform.TransformPoint(left.Value)).magnitude;

            distanceJoint2D.anchor = left.Value;
        }
        if (right.HasValue) {
            rightSurfaceDist = CableJointsAlgorithm.CirclePointDistance(linkTo.transform.TransformPoint(distanceJoint2D.connectedAnchor) , linkTo.transform.TransformPoint(right.Value), linkTo);

            // rightSurfaceDist = (linkTo.transform.TransformPoint(distanceJoint2D.connectedAnchor) - linkTo.transform.TransformPoint(right.Value)).magnitude;
            
            distanceJoint2D.connectedAnchor = right.Value;
        }

        return (leftSurfaceDist, rightSurfaceDist);
    }

    /* VISUALS */
    private void Update() {
        if (text != null) {
            text.transform.position = transform.position;
            //text.transform.rotation = transform.rotation;
            text.GetComponent<TextMeshPro>().text = 
                gameObject.name + "\n" +
                (clockwise ? "cw" : "ccw") + " - " + movement + "\n" +
                " Mass: "+GetComponent<Rigidbody2D>().mass.ToString("0.00") + 
                " Dist: " + (distanceJoint2D == null ? " - "
                    : distanceJoint2D.distance.ToString("0.00") + "\n"+
                      "Slack: "+(distanceJoint2D.distance-actualDistance).ToString("0.00"));
                
        }
    }

    // Update is called once per frame
    void OnDrawGizmos() {
        foreach (var distanceJoint in gameObject.GetComponents<DistanceJoint2D>()) {
            Gizmos.color = new Color(1, .3f, 0);
            var cableStart = transform.TransformPoint(distanceJoint.anchor);
            var cableEnd = distanceJoint.connectedBody.transform.TransformPoint(distanceJoint.connectedAnchor);
            Gizmos.DrawLine(cableStart, cableEnd);
            Gizmos.color = Color.yellow;
            Gizmos.DrawCube(cableStart, new Vector3(0.1f, 0.1f, 0.1f));
            Gizmos.color = Color.red;
            Gizmos.DrawCube(cableEnd, new Vector3(0.1f, 0.1f, 0.1f));
        }
    }

    public enum RotationType {
        Fixed,
        Rotatable,
        Powered,
        Free
    }
}