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

public class HeadMovement : MonoBehaviour
{
    ///目前暂时暴露成PUBLIC以方便调试
    public Transform kTargetLookAt = null;/*看向的目标*/
    public Transform kHeadTrs = null;/*头*/
    public Transform kRoot = null;/*PLAYER的根节点*/
    public float fEurlAngleRangeCheck = 80f;/*头部每次转向的最大角度(会分别检查头部3个轴的转向分量)*/
    public float fMaxDistance = 8f;/*距离目标超过这个距离，就不注视*/
    public float fMinDistance = 0.5f;/*距离目标超过小于这个距离，就不注视*/
    public float fLerpSpeed = 0.3f;/*头部转向运动的插值，建议在0.3左右*/

    //上一祯的头部旋转量（相对世界坐标）
    private Quaternion kLastFace2 = Quaternion.identity;
    void LateUpdate()
    {
        if (kTargetLookAt == null)
        {
            return;
        }
        if (kLastFace2.Equals(Quaternion.identity))
        {
            kLastFace2 = kHeadTrs.rotation;
        }
        Vector3 _vecDirDst =
            (kTargetLookAt.transform.position - kHeadTrs.position).normalized;
        float _fDistance =
            Vector3.Distance(kRoot.position, kTargetLookAt.position);
        Quaternion _kSrcDstQuDlt = Quaternion.FromToRotation(kRoot.forward, _vecDirDst);
        if (this._checkFloatEurlRange(_kSrcDstQuDlt.eulerAngles, fEurlAngleRangeCheck) == false || _fDistance > fMaxDistance || _fDistance < fMinDistance)
        {///处于越界状态，这个时候，头要往正常地转
            _vecDirDst = kRoot.forward;
        }
        Quaternion _quSrc = kRoot.rotation;
        kRoot.forward = _vecDirDst;
        Quaternion _quChild = Quaternion.Lerp(kLastFace2, kHeadTrs.rotation, fLerpSpeed);
        kRoot.rotation = _quSrc;
        kHeadTrs.rotation = _quChild;
        kLastFace2 = _quChild;
    }

    ///对3个角度分量进行检查，如果超过_fRangeAbs
    bool _checkFloatEurlRange(Vector3 _vecSrc, float _fRangeAbs)
    {
        float _fRangeAbs_ = Mathf.Abs(_fRangeAbs);
        float[] _fTempArr = new float[] { _vecSrc.x, _vecSrc.y, _vecSrc.z };
        for (int _iCounter = 0;_iCounter < _fTempArr.Length;++_iCounter)
        {
            _fTempArr[_iCounter] = Mathf.Abs(_fTempArr[_iCounter]);
            if (_fTempArr[_iCounter] >= 0f && _fTempArr[_iCounter] < _fRangeAbs_)
            {
                continue;
            }
            if (_fTempArr[_iCounter] >= 360f - _fRangeAbs_ && _fTempArr[_iCounter] < 360f)
            {
                continue;
            }
            return false;
        }
        return true;
    }


}