using UnityEngine;
using System.Collections;

namespace Thousandto.Cinematic
{
    /// <summary>
    /// 振动效果
    /// </summary>
    public class CinematicShake : MonoBehaviour
    {
        //持续时间
        private float _duration = 2f;
        //振动强度，值越大，频率越小
        private float _strenth = 3f;
        //每一帧位置偏移
        private Vector3 _deltaPos = Vector3.zero;
        //保存之前的位置
        private Vector3 _oldPosition;
        //开始振动标记
        private bool _startShake = false;
        // Use this for initialization
        void Start()
        {

        }

        public void StartShake(float duration = 2f, float strenth = 3f)
        {
            _duration = duration;
            _strenth = strenth;
            if (strenth <= 0)
                _strenth = 0.1f;

            _oldPosition = transform.localPosition;
            _deltaPos = Vector3.zero;
            _startShake = true;
            this.enabled = true;
        }

        private void OnShakeEnd()
        {
            transform.localPosition = _oldPosition;
            this.enabled = false;
        }

        // Update is called once per frame
        void Update()
        {
            if (!_startShake) return;

            if (_duration > 0)
            {
                _duration -= Time.deltaTime;
                transform.localPosition -= _deltaPos;
                _deltaPos = UnityEngine.Random.insideUnitSphere / _strenth;
                transform.localPosition += _deltaPos;
            }
            else
            {
                _duration = 0;
                _startShake = false;
                OnShakeEnd();
            }
        }
    }

}