[HELP] Fog of War

Is there a way to create fog of war? Not just darkening the invisible area, but to see objects that were there at the moment you've seen them?

Thought about ImageManipulator, but then what if i have 2 sprites on a tile, like enemy and item. Create masks above them for each sprite?

I would say to try using the canvas object.

There are some examples of ways to do fog of war in this topic: http://www.scirra.com/forum/viewtopic.php?f=3&t=6674&p

I mean FOW like in the strategies. For ex. - i saw enemy's building, but when i don't see this place, i still can see the building, even if it already destructed. And when i see this place again i see that there's nothing left.

I'm working on this model of fov right now combining LOS and Canvas, still some problems. Maybe anyone already implemented this, and can donate a prototype?

Added:

Here's my FOW implementation prototype http://www.box.net/shared/9tzdjybr3c

Inverted shadowcaster can be very useful, is it implemented?

A layer effect could easily achieve that. It wouldn't affect collisions though, and I don't even know if there are collisions for that object.