c# - Unity 如何执行它的方法？

Question

我在 Unity3D 中只有很少的经验，但我注意到派生自 MonoBehaviour 的类可能包含具有预定义签名的函数，这些函数将以特殊方式调用。例如，如果我写:

void Update()
{
  //some code
}

此方法将在每一帧调用。

我想在 Unity 内部有某种无限循环，它会在场景中的每个对象的每一帧调用 Update 方法。但是它怎么知道这个对象实际上提供了Update方法的实现呢？如果 Update 是 MonoBehaviour 类中的方法的重写，那将是很清楚的，但是从语法判断(以及您可以使用任何访问权限实现此类方法的事实修饰符)不是。那里有反射魔法吗？

Answer 1

http://blogs.unity3d.com/2015/12/23/1k-update-calls/

No, Unity doesn’t use System.Reflection to find a magic method every time it needs to call one.

Instead, the first time a MonoBehaviour of a given type is accessed the underlying script is inspected through scripting runtime (either Mono or IL2CPP) whether it has any magic methods defined and this information is cached. If a MonoBehaviour has a specific method it is added to a proper list, for example if a script has Update method defined it is added to a list of scripts which need to be updated every frame.

During the game Unity just iterates through these lists and executes methods from it — that simple. Also, this is why it doesn’t matter if your Update method is public or private.