需要幫助在c＃遊戲代碼

Question

我正在製作一個統一的塔防遊戲，但我卡住了。我希望我的槍或炮塔面對敵人，直到他們超出範圍，但每0.5秒後它會更新並面對其範圍內的另一個敵人，儘管第一個敵人也在範圍內。

這裏是我的代碼：

void Start() 
{ 
    InvokeRepeating("UpdateTarget", 0f , 0.5f); 
} 

void UpdateTarget() 
{ 
    GameObject[] enemies = GameObject.FindGameObjectsWithTag(enemyTag); 
    float shortestDistance = Mathf.Infinity; 
    GameObject nearestEnemy = null; 

    foreach (GameObject enemy in enemies) 
    { 
     float distanceToEnemy = Vector3.Distance(transform.position, enemy.transform.position); 
     if (distanceToEnemy < shortestDistance) 
     { 
      shortestDistance = distanceToEnemy; 
      nearestEnemy = enemy; 
     } 
    } 

    if (nearestEnemy != null && shortestDistance <= range) 
    { 
     target = nearestEnemy.transform;   
    } 
    else 
    { 
     target = null; 
    }   
} 

Answer 1

GameObject.FindGameObjectsWithTag對性能的影響更大，我會建議你創建一個圓撞機2D並將其設置爲觸發，當OnTriggerEnter2D被稱爲可以獲取敵人然後舉起一面旗幟，以便其他敵人在此之後不會被觸發，當對該敵人調用OnTriggerExit2D時，您可以開始尋找另一個敵人或選擇其中一個仍然在該碰撞者半徑內的敵人。

private bool _foundEnemy; 
private Enemy _currentEnemy; 

private void OnTriggerEnter2D(Collider2D collision) 
{ 
    if (_foundEnemy) return; 

    _currentEnemy = collision.GetComponent<Enemy>(); 
    // your code here 
    _foundEnemy = true; 
} 

private void OnTriggerExit2D(Collider2D collision) 
{ 
    if(_currentEnemy!=null && collision.GetComponent<Enemy>() == _currentEnemy) 
     _foundEnemy = false; 
} 

Answer 2

你必須包括在UpdateTarget一個測試，應先檢查，如果nearestEnemy仍然在範圍和在這種情況下退出該功能，否則尋找新的目標。

邏輯應該是這個樣子：

//keep old target? 
if(nearestEnemy != null) 
{ 
    //calculate distance of current target here.. 
    if(distance <= range) 
    return; //keep this enemy as target 
} 
//here comes your code for finding a new target... 

Answer 3

你是不是你想達到什麼樣的行爲完全清楚，但似乎是鎖定目標，直到它死了，然後才切換到另一個目標。這是你的代碼中的一個簡單的修復;但我發現了幾個其他問題：

1. 冗餘代碼，如塊和變量。
2. 非常多的例子如何失敗要遵循Single Responsibility Principle。
3. 您不需要「其中一個或另一個」方法，因爲其他答案正在顯示。你可以得到這兩個行爲與一個簡單的boolean flag作爲交換機。

這裏是一些註釋代碼佔所有這些東西，希望提供可以學習，從參考：

//Defines how to get and compare distance; used during sorting 
public class DistanceComparer<T> : IComparer<T> where T : GameObject { 
    public int Compare(T a, T b) { 
     return Vector3.Distance(a.transform.position, b.transform.position); 
    } 
} 

public var bool lockToTargetUntilDead = true; //Should lock to target till it's dead (true)? Or switch to nearest if the nearest changes (false)? 

//Finds nearest enemy 
GameObject FindNearestEnemy() { 
    var enemies = GameObject.FindGameObjectsWithTag(enemyTag); 
    if (enemies==null || enemies.Length==0) return null; //No enemies anywhere 
    Array.Sort(enemies, new DistanceComparer()); //Sort enemies by distance 
    return enemies[0]; //Return closest enemy 
} 

//Determines if enemy is within range (Note: If enemy is null, it's not in range =P) 
bool IsWithinRange(GameObject enemy) { 
    return enemy != null && Vector3.Distance(transform.position, enemy.transform.position) <= range; 
} 

//Updates target 
void UpdateTarget() { 
    var nearestEnemy = FindNearestEnemy(); 
    if(!IsWithinRange(nearestEnemy)) { //No enemies within range... 
     if(target != null) target = null; //Forget current target. 
     return; //Return-early. 
    } 
    if(lockToTargetUntilDead && target!=null) return; //If locking to current target and it ain't dead yet, return-early 
    target = nearestEnemy; //If not locking to target, or doesn't have a target, new target! 
} 

void Start() { 
    InvokeRepeating("UpdateTarget", 0f , 0.5f); 
}