程式碼(Trigger吃子彈).txt

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


public class OfflineBullet : MonoBehaviour
{
    public GameObject LittleCrack;
    public GameObject Explosion;
    public GameObject AttackHotExplose;
    public GameObject BulletDestory;

    public float BulletSpeed;
    private float StartTime;
    private float FlyTime;

    public bool HasStop = false;//子彈狀態：0.射出未撞牆  1.子彈撞牆過，反彈中
    public bool isOnCollider = false;
    private bool HasFirstEnterCollider = false;

    private Vector3 LastForce;
    private Vector3 ReflectVector;

    private void OnCollisionEnter(Collision collision)
    {
        
        
        if (!HasFirstEnterCollider)
        {
            HasFirstEnterCollider = true;
            //只執行一次ColliderEnetr(可能一次碰到多個Collider)


            print("collidre");


            Vector3 point = collision.GetContact(0).point;

            /*switch (ColliderObject.tag)
            {
                case "BattleField":
                    if (!HasStop)
                    {
                        HasStop = true;


                        /*Vector3 thisForward = this.transform.forward;//導好thisForward才不用一直寫
                        Vector3 BulletToContact = collision.GetContact(0).point - this.transform.position;//導好BulletToContact才不用一直寫
                        RaycastHit hit;
                        if(Physics.Raycast(this.transform.position, BulletToContact, out hit))
                            ReflectVector = hit.normal;//設定ReflectVector(第一個碰到點的法線)//不用collision.GetContact(0).normal是因為這是get"把子彈推出去的方向"，和get表面的normal不一樣

                        print(ReflectVector);

                        float ContactDistance = BulletToContact.magnitude;
                        float ContactAngle = Vector3.Angle(ReflectVector, BulletToContact);//髮線與觸控點到子彈線的夾角

                        float VertialDistance = ContactDistance * Mathf.Cos(Mathf.Deg2Rad * ContactAngle);//下陷垂直距離(Deg2Rad是/180 * pi的結果)

                        float RealAngle = Vector3.Angle(ReflectVector, -thisForward);//髮線與子彈forward的夾角
                        float RealForwardDistance = VertialDistance / Mathf.Cos(Mathf.Deg2Rad * RealAngle);//真正下陷距離
                        
                        this.transform.position = this.transform.position - thisForward * (RealForwardDistance + 0.1f);//吃子彈修正完成
                    }
                    

                   


                    //newBullet.GetComponent<OfflineBullet>().DetactBulletOverFly();//確認卡子彈調整後是否不在牆上了


                    
                    //反彈後子彈打牆處理
                    {

                        this.GetComponent<Rigidbody>().AddForce(-LastForce);//先停止在施力，比較符合彈射的感覺


                        LastForce = Vector3.Reflect(LastForce, ReflectVector);
                        this.GetComponent<Rigidbody>().AddForce(LastForce);
                        //子彈被打到從牆壁反彈模擬
                    }


                    break;
                case "AttackStuff"://空中相遇(進入Trigger不會執行)
                    if (FlyTime <= ColliderObject.GetComponent<OfflineBullet>().FlyTime)
                        Destroy(this.gameObject);
                    //後發射者毀滅(或一出來就碰到者，用於反彈時Collider沒碰，生出的Trigger碰時)

                    ColliderObject.GetComponent<Rigidbody>().AddForce(this.transform.forward * 2000f * 2f);
                    break;
                case "Player"://打到玩家
                    ColliderObject.GetComponent<BeHit>().HasBeHit();
                    Destroy(this.gameObject);
                    break;
            }
            //子彈碰撞處理(Collider)    */     
        }     
    }


    private void OnTriggerEnter(Collider other)//不用isKinematic + OnColliderEnter來做無碰撞偵測原因 : 1.不用collision.GetContact(0).normal了 2.continuous speculative仍有可能tunneling(雖然旋轉時不會，但快速移動會，不符合目的)，isKinematic只能用speculative
    {

        print("hit");


        if (!HasFirstEnterCollider)
        {
            HasFirstEnterCollider = true;
            //只執行一次ColliderEnetr(可能一次碰到多個Collider)


            switch (other.tag)
            {
                case "BattleField":
                    if (!HasStop)
                        BulletInWallFixed(other);                      

                    break;
                case "AttackStuff":
                    if (!HasStop)
                        Destroy(this.gameObject);
                    else
                    {
                        LastForce = Vector3.Reflect(other.transform.forward, ReflectVector) * 1000f;
                        this.GetComponent<Rigidbody>().AddForce(LastForce);
                        this.GetComponent<Collider>().isTrigger = false;
                        //子彈被打到從牆壁反彈模擬 
                    }

                    break;

            }



            /*if (other.tag == "AttackStuff")//開始反彈
            {
                LastForce = Vector3.Reflect(other.transform.forward, ReflectVector) * 1500;
                this.GetComponent<Rigidbody>().AddForce(LastForce);
                //子彈被打到從牆壁反彈模擬 

                if (FlyTime <= other.gameObject.GetComponent<OfflineBullet>().FlyTime)
                    Destroy(this.gameObject);
                //沒HasStop者毀滅(不知為何Collider進入Trigger會執行，所以要if)
            }*/
        }
        //主運算程式

        if(other.tag != "BattleField")//吃子彈特效會播，避免
            UseParticle(other);//粒子特效
    }


    private void OnTriggerStay(Collider other)
    {
        if (!HasStop)
            BulletInWallFixed(other);
    }


    private void OnTriggerExit(Collider other)
    {
        HasFirstEnterCollider = false;
    }
    //離開Collision回復HasFirstEnetrCollider



    private void Start()
    {
        StartTime = Time.time;
    }
    private void Update()
    {
        FlyTime = Time.time - StartTime;
        if (FlyTime > 5f)
        {
            if(HasStop)
                Destroy(this.gameObject);
        }
        if (Time.time - StartTime > 20f)
            Destroy(this.gameObject);
        //預防射向天空，要一直計算子彈，不會被消滅
    }
    //計算FlyigTime

    

    private void UseParticle(Collider other)
    {
        switch (other.tag)
        {
            case "BattleField":
                if (HasStop)
                {
                    Destroy(this.GetComponentsInChildren<Transform>()[1].gameObject);//取消拖曳線特效
                    GameObject NewLittleCrack = Instantiate(LittleCrack, this.transform.position, other.transform.rotation);
                    NewLittleCrack.GetComponent<Renderer>().material.color = other.GetComponent<Renderer>().material.color;
                    Destroy(NewLittleCrack, 0.8f);
                }
                break;
            case "Player":
                GameObject NewExplosion = Instantiate(Explosion, this.transform.position, Quaternion.identity);
                NewExplosion.GetComponentsInChildren<Transform>()[1].GetComponent<Renderer>().material.color = other.GetComponent<Renderer>().material.color;
                Destroy(NewExplosion, 0.8f);
                break;
            case "AttackStuff":
                GameObject NewAttackHitExplose = Instantiate(AttackHotExplose, (this.transform.position + other.transform.position) / 2, Quaternion.identity);
                Destroy(NewAttackHitExplose, 0.8f);
                break;
        }      
    }
    //粒子特效

    private void BulletInWallFixed(Collider other)
    {
        Vector3 thisForward = this.transform.forward;//導好thisForward才不用一直寫
        Vector3 thisPosition = this.transform.position;//導好thisPosition才不用一直寫
        float FrameDistance = BulletSpeed * Time.deltaTime;//子彈一幀前進距離

        Vector3 BeforeBulletPosition = thisPosition - 2 * thisForward * FrameDistance;//找兩幀前的位置(前兩幀: 未碰撞->前一幀:處理碰撞(Trigger沒有) + 確認Continuse(當兩幀到一幀間有東西，觸發碰撞)->此幀:OnTriggerEnter)，此為實驗結果，無查資料(Continous原理有查到)
        
        Debug.DrawLine(thisPosition, BeforeBulletPosition, Color.red, 10f);
        Debug.DrawLine(BeforeBulletPosition,BeforeBulletPosition + thisForward * (FrameDistance + 0.5f), Color.blue, 5f);
        
        RaycastHit hit;
        Ray ray = new Ray(BeforeBulletPosition, thisForward);

        

        bool CanStop = true;
        
        
        if (Physics.Raycast(ray, out hit, FrameDistance + 0.25f))//兩幀前位置(未碰撞才能確保沒有陷入牆中)往前(1個FrameDistance+子彈半徑)有東西(記得把queries hit triggers關掉，不然raycast會打到子彈)
        {
            this.transform.position = hit.point;//這就是吃子彈修正(前一幀射出的Raycast打到的點)
            ReflectVector = hit.normal;//之後要用
        }
        else//沒有陷進去
        {
            Vector3 SimlarContactPoint = other.ClosestPoint(BeforeBulletPosition);//以兩幀前子彈位置(確認必在尖端後端)找最近點最接近碰撞點，確認找到第一處控面的點(不在兩幀前最近點可在另一面)(前方沒東西時。我們能確定1幀前沒有在collider裡面)
            Vector3 BeforeBulletToSimlarPoint = SimlarContactPoint - BeforeBulletPosition;//get ReflectVector用

            Debug.DrawRay(BeforeBulletPosition, BeforeBulletToSimlarPoint, Color.green, 7f);
            ray = new Ray(BeforeBulletPosition, BeforeBulletToSimlarPoint);
            if (Physics.Raycast(ray, out hit))
                ReflectVector = hit.normal;//不用collision.GetContact(0).normal是因為這是get"把子彈推出去的方向"，和get表面的normal不一樣
            else
                ReflectVector = new Vector3(0f, 0f, 0f);//其實一定打的到，只是編譯器不知道，所以隨便給值
             //得到ReflectVector

            ray = new Ray(BeforeBulletPosition + thisForward * (FrameDistance + 0.5f), -ReflectVector);//以一幀+子彈直徑前位置(確認必在尖端前端)為始向下找地板
            Debug.DrawRay(BeforeBulletPosition + thisForward * (FrameDistance + 0.5f), -ReflectVector, Color.black, 10f);
            if (!Physics.Raycast(ray,out hit) || hit.normal == ReflectVector)//地板與other是同一平面，就不會是碰邊邊，會是沒陷太深，再執行一次
            {
                print("a");
                HasFirstEnterCollider = false;//讓程式可以再跑一次
                CanStop = false;
            }
            else//碰邊邊
            {
                Vector3 BulletToSimlarPoint = SimlarContactPoint - thisPosition;//主要計算用
                             
                float SimlarAngle = Vector3.Angle(BulletToSimlarPoint, ReflectVector);
                float SimlarDistance = BulletToSimlarPoint.magnitude;

                float VertialDistance = SimlarDistance * Mathf.Cos(Mathf.Deg2Rad * SimlarAngle);//下陷垂直距離(Deg2Rad是/180 * pi的結果)

                float RealAngle = Vector3.Angle(ReflectVector, -thisForward);//髮線與子彈forward的夾角
                float RealForwardDistance = VertialDistance / Mathf.Cos(Mathf.Deg2Rad * RealAngle);//真正下陷距離

                Vector3 SimlarBullet = thisPosition - thisForward * RealForwardDistance;//找到平行尖端的點，確認頂一夏ClosestPoint必找到尖端


                SimlarContactPoint = other.ClosestPoint(SimlarBullet);//以SimlarBullet找最近點(原本為前兩幀)，確認找到尖端
                Vector3 CloestPointToBullet = thisPosition - SimlarContactPoint;//最近點到子彈向量

                Debug.DrawLine(thisPosition, SimlarContactPoint, Color.yellow, 10f);

                float CloestPointDistance = CloestPointToBullet.magnitude;

                float FixingAndle = Vector3.Angle(CloestPointToBullet, thisForward);//最近點到子彈向量與Forward的夾角
                float FixedForwardDistance = CloestPointDistance * Mathf.Cos(Mathf.Deg2Rad * FixingAndle);//返回距離

                this.transform.position = thisPosition - thisForward * FixedForwardDistance;//返回完成
                //返回到thisForward離最近點最近的位置
            }
        }

        if (CanStop)//可能沒陷進去不執行
        {
            HasStop = true;
            this.GetComponent<Rigidbody>().AddForce(-this.transform.forward * BulletSpeed, ForceMode.Impulse);//確認修正完成後才停止子彈
            UseParticle(other);//不確定何時做完修正，所以做完就播
        }
    }
    //吃子彈修正

    private void OnDestroy()
    {
        if (HasStop || !HasFirstEnterCollider)//在第一次碰撞時不撥放
        {
            GameObject NewBulletDestory = Instantiate(BulletDestory, this.transform.position, this.transform.rotation);
            NewBulletDestory.GetComponent<Renderer>().material.color = this.GetComponent<Renderer>().material.color;
            Destroy(NewBulletDestory, 0.8f);
        }
    }
}