GunSystem/Assets/Script/Menu/CaculateEularEngle.cs

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

public class CaculateEularEngle : MonoBehaviour {
    public GameObject self_;
    public GameObject otherHand;
    private Vector3 eularEngle;

	// Use this for initialization
	void Start () {
		
	}
	
	// Update is called once per frame
	void Update () {
        eularEngle = caculateEularEngle();
        otherHand.transform.localEulerAngles = eularEngle;
	}

    Vector3 caculateEularEngle()
    {
        float x = self_.transform.position.x - otherHand.transform.position.x;
        float y = self_.transform.position.y - otherHand.transform.position.y;
        float z = self_.transform.position.z - otherHand.transform.position.z;
        float engleX = 0.0f;
        float engleY = 0.0f;
        //float engleZ = 0.0f;
        if (x >= 0f)
        {
            engleY = -Mathf.Atan(z / x) * 180f / Mathf.PI - 90f;
        }
        else
        {
            engleY = 180.0f - Mathf.Atan(z / x) * 180f / Mathf.PI - 90f;
        }
        if (z >= 0f)
        {
            engleX = Mathf.Atan(y / z) * 180f / Mathf.PI;
        }
        else
        {
            engleX = -Mathf.Atan(y / z) * 180f / Mathf.PI;
        }
        //engleZ = leftHand.transform.eulerAngles.z;
        Vector3 eularEngle = new Vector3(-engleX, engleY + 180f, 0.0f);
        return eularEngle;
    }
}