static void CreateInstance()
{
// If scripts are recompiled the the static variable will be lost.
// Some users recompile scripts in play mode and then reload the scene (https://forum.arongranberg.com/t/rts-game-pathfinding/6623/48?u=aron_granberg)
// which makes this a requirement
instance = FindObjectOfType <BatchedEvents>();
if (instance == null)
{
var go = new UnityEngine.GameObject("Batch Helper");
instance = go.AddComponent <BatchedEvents>();
go.hideFlags = UnityEngine.HideFlags.HideAndDontSave;
DontDestroyOnLoad(go);
}
}
void OnEnable()
{
if (instance == null)
{
instance = this;
}
if (instance != this)
{
// We cannot destroy the object while it is being enabled, so we need to delay it a bit
#if UNITY_EDITOR
// This is only important in the editor to avoid a build-up of old managers.
// In an actual game at most 1 (though in practice zero) old managers will be laying around.
// It would be nice to use a coroutine for this instead, but unfortunately they do not work for objects marked with HideAndDontSave.
UnityEditor.EditorApplication.update += DelayedDestroy;
#endif
return;
}
}
static void CreateInstance()
{
// If scripts are recompiled the the static variable will be lost.
// Some users recompile scripts in play mode and then reload the scene (https://forum.arongranberg.com/t/rts-game-pathfinding/6623/48?u=aron_granberg)
// which makes handling this a requirement.
// Here one might try to look for existing instances of the class that haven't yet been enabled.
// However, this turns out to be tricky.
// Resources.FindObjectsOfTypeAll<T>() is the only call that includes HideInInspector GameObjects.
// But it is hard to distinguish between objects that are internal ones which will never be enabled and objects that will be enabled.
// Checking .gameObject.scene.isLoaded doesn't work reliably (object may be enabled and working even if isLoaded is false)
// Checking .gameObject.scene.isValid doesn't work reliably (object may be enabled and working even if isValid is false)
// So instead we just always create a new instance. This is not a particularly heavy operation and it only happens once per game, so why not.
// The OnEnable call will clean up duplicate managers if there are any.
var go = new GameObject("Batch Helper")
{
hideFlags = HideFlags.DontSave | HideFlags.NotEditable | HideFlags.HideInInspector | HideFlags.HideInHierarchy
};
instance = go.AddComponent <BatchedEvents>();
DontDestroyOnLoad(go);
}