_xiaofang/xiaofang/Assets/Obi/Samples/RopeAndRod/SampleResources/Scripts/TangledPeg.cs

using System.Collections;
using UnityEngine;
using Obi;

[RequireComponent(typeof(Rigidbody))]
public class TangledPeg : MonoBehaviour
{
    public TangledPegSlot currentSlot;
    public Collider floorCollider;
    public ObiRope attachedRope;

    [Header("Movement")]
    public float stiffness = 200;
    public float damping = 20;
    public float maxAccel = 50;
    public float minDistance = 0.05f;


    public Rigidbody rb { get; private set; }
    public ObiRigidbody orb { get; private set; }

    void Awake()
    {
        rb = GetComponent<Rigidbody>();
        orb = GetComponent<ObiRigidbody>();

        // Ignore collisions with the floor:
        Physics.IgnoreCollision(GetComponent<Collider>(), floorCollider);

        // Initialize the peg's current slot, if any:
        if (currentSlot != null)
        {
            currentSlot.currentPeg = this;
            transform.position = currentSlot.transform.position;
        }
    }

    public float MoveTowards(Vector3 position)
    {
        Vector3 vector = position - transform.position;
        float distance = Vector3.Magnitude(vector);

        // simple damped spring: F = -kx - vu
        Vector3 accel = stiffness * vector - damping * rb.velocity;

        // clamp spring acceleration:
        accel = Vector3.ClampMagnitude(accel, maxAccel);

        rb.AddForce(accel, ForceMode.Acceleration);

        return distance;
    }

    public void DockInSlot(TangledPegSlot slot)
    {
        StopAllCoroutines();
        StartCoroutine(MoveTowardsSlot(slot));
    }

    public void UndockFromCurrentSlot()
    {
        if (currentSlot != null)
        {
            currentSlot.currentPeg = null;
            rb.isKinematic = false;
        }
    }

    private IEnumerator MoveTowardsSlot(TangledPegSlot slot)
    {
        float distance = float.MaxValue;
        orb.kinematicForParticles = true;

        while (distance > minDistance)
        {
            distance = MoveTowards(slot.transform.position);
            yield return 0;
        }

        currentSlot = slot;
        currentSlot.currentPeg = this;
        transform.position = currentSlot.transform.position;
        rb.isKinematic = true;
        orb.kinematicForParticles = false;
    }
}