Spring Joint 2D（可能）导致 transform.position 错误

Posted 2023-04-12

【中文标题】Spring Joint 2D（可能）导致 transform.position 错误

【英文标题】：Spring Joint 2D (maybe) causing transform.position errors

【发布时间】：2020-06-20 13:18:33

【问题描述】：

在您看到问题所在后，我知道标题可能会产生误导，但我真的不知道如何命名这个问题。 第一张图显示问题。

白线表示玩家与名为 hook 的游戏对象之间的距离。靠近钩子的蓝色精灵球体是 SpringJoint2D.connectedBody。

它们（白线和蓝色精灵）都使用相同的值：hook.transform.position。

这是我认为引起问题或至少揭示最多的代码 sn-ps：

SpringJoint2D sn-p：

if (Input.GetMouseButtonDown(0))
        
            hook = FindClosestObject(radius, "Hook");
            if(hook != null)
            
                joint.enabled = true;
                joint.connectedBody = hook;
                joint.connectedAnchor = hook.transform.position;
                Debug.Log("Click.");
                Debug.Log(hook);
            
            
        
        if (Input.GetMouseButtonUp(0))
        
            joint.enabled = false;
            joint.connectedBody = null;
        

Debug.DrawLine sn-p:

if (hook != null)
        
            joint.distance = Vector3.Distance(hook.transform.position, transform.position) / 2;
            Debug.DrawLine(transform.position, hook.transform.position);
        

这是完整的代码：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PlayerScript : MonoBehaviour

    
    public float radius;

    private SpringJoint2D joint;
    private Rigidbody2D hook = new Rigidbody2D();


    // Start is called before the first frame update
    void Start()
    
        joint = GetComponent<SpringJoint2D>();
    

    // Update is called once per frame
    void Update()
    
        //touch.phase == TouchPhase.Began
        if (Input.GetMouseButtonDown(0))
        
            hook = FindClosestObject(radius, "Hook");
            if(hook != null)
            
                joint.enabled = true;
                joint.connectedBody = hook;
                joint.connectedAnchor = hook.transform.position;
                Debug.Log("Click.");
                Debug.Log(hook);
            
            
        
        if (Input.GetMouseButtonUp(0))
        
            joint.enabled = false;
            joint.connectedBody = null;
        
        //foreach (Touch touch in Input.touches)
        //

        //
        if (hook != null)
        
            joint.distance = Vector3.Distance(hook.transform.position, transform.position) / 2;
            Debug.DrawLine(transform.position, hook.transform.position);
        

        
    

    private void OnDrawGizmos()
    
        Gizmos.color = Color.green;
        Gizmos.DrawWireSphere(transform.position, radius);
        if (hook != null) 
            Gizmos.DrawLine(transform.position, hook.transform.position);
    

    public Rigidbody2D FindClosestObject(float radius, string tag)
    
        GameObject[] gos;
        gos = GameObject.FindGameObjectsWithTag(tag);
        Rigidbody2D closest = null;
        float distance = radius;
        Vector3 position = transform.position;
        foreach (GameObject go in gos)
        
            Vector3 diff = go.transform.position - position;
            float curDistance = diff.sqrMagnitude;
            if (curDistance < distance)
            
                closest = go.GetComponent<Rigidbody2D>();
                distance = curDistance;
            
        
        return closest;
    

【参考方案1】：

啊，我只是愚蠢。

如果您还分配了 connectedRigidbody2D，则无需分配 connectedAnchor connectedAnchor 是相对于 connectedRigidbody2D 位置的偏移量...