Asset is not unloaded even if GameObject destroyed

Questions & Answers
1

I believe that this question was discussed many times, but still.

Consider an example:
We have some kind of singleton class which exists all the time.
It has public GameObject MyGameObject;

We load scene1. And set MyGameObject = GameObject.Find(“Whatever”);
Then we load scene2.

Now Debug.Log(MyGameObject == null) will say “true”. I suppose somekind of wrapper still exists, which knows that this GameObject doesn’t exists anymore. We can’t even find it using FindObjectsOfTypeAll (and we can’t find source asset). So Unity knows that object was destroyed, but it still keeps texture alive! (after calling UnloadUnusedAssets of course).

So until we excatly set MyGameObject = null; we can’t get rid of texture it uses in our memory.

This is very simple example, in reality everything can be very unobvious. We can reference another class, which can refenrece gameobject which was destroyed and it’s component can has delegate in which closure still exists local variable of another gameobject and etc…
I understand that this is our problem and we should keep eyes on our code, but I’m really interested in reasonable explanation why is it so?

2

Unity doesn’t unload textures from memory if objects using them are destroyed. It was mentioned in some of the talks from Unite’12. To get rid of them you

  1. either have to call Resources.UnloadUnusedAssets
  2. or change level

In your case you sya that you use Resources.UnloadUnusedAssets and load another level. So you use both of them and textures are not unloaded.

First of all why are you sure that textures are still there?
Are you sure that this gameobject doesn’t have don’t destroy when loading another scene flag set?
Are you sure that it is not referenced by any behavior with such flag?

Otherwise it looks like a bug.