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

public?class?Trajectory?:?MonoBehaviour
{

????//?Use?this?for?initialization??
????void?Start（）
????{
????????//?開始測試??
????????Vector3?end?=?transform.position;
????????end.x?=?end.x?*?-1;
????????Fire（transform.position?end）;
????}

????//?Update?is?called?once?per?fram??
????void?Update（）
????{
????????if?（_isFiring）
????????{
????????????UpdateArrow（）;
????????}
????}

????//?所有變量??
????public?float?rotateX?=?45;??????//?箭的最大X軸旋轉角度??
????public?float?speed?=?10;????????//?箭的速度??
????public?float?height?=?10;???????//?箭的最大高度???
????private?Vector3?_startPos?_stopPos?_curPos;????//?起始位置，目標位置，當前位置??
????private?float?_angleToStop;?????//?從起始點到目標點的角度??
????private?float?_startHeight?_stopHeight;?//?起始高度，結束高度??
????private?bool?_isFiring?=?false;?????//判斷箭是否正在移動??
????private?float?_totalDistance?_curDistance;??//?總距離，?當前距離??
????private?Vector3?_curRotation;?//?當前的旋轉角度??

????//?發射函數，你只要調用這一個函數就能發射箭了??
????public?void?Fire（Vector3?start?Vector3?stop）
????{
????????_startPos?=?start;
????????_stopPos?=?stop;
????????_angleToStop?=?GetAngleToStop（start?stop）;?//?計算?起始位置?到?目標位置的角度??
????????_startHeight?=?start.y;
????????_stopHeight?=?stop.y;
????????_curDistance?=?0;

????????//?計算總距離??
????????Vector3?v?=?_stopPos?-?_startPos;
????????_totalDistance?=?Mathf.Sqrt（v.x?*?v.x?+?v.z?*?v.z）;

????????//?設置當前位置??
????????transform.position?=?start;
????????_curPos?=?start;

????????//?設置當前X，Y軸的旋轉角度??
????????Vector3?rotation?=?transform.eulerAngles;
????????if?（rotateX?>?0）
????????{
????????????rotation.x?=?-rotateX;
????????}
????????rotation.y?=?_angleToStop;

????????transform.eulerAngles?=?rotation;
????????_curRotation?=?rotation;

????????//?設置判斷爲發射狀態，讓Update函數能夠更新??
????????_isFiring?=?true;
????}

????//?計算?起始位置?到?目標位置的角度??
????private?float?GetAngleToStop（Vector3?startPos?Vector3?stopPos）
????{
????????stopPos.x?-=?startPos.x;
????????stopPos.z?-=?startPos.z;

????????float?deltaAngle?=?0;
????????if?（stopPos.x?==?0?&&?stopPos.z?==?0）
????????{
????????????return?0;
????????}
????????else?if?（stopPos.x?>?0?&&?stopPos.z?>?0）
????????{
????????????deltaAngle?=?0;
????????}
????????else?if?（stopPos.x?>?0?&&?stopPos.z?==?