Is it possible to reveal a layer using a mask ?

Hi guys,

I was wondering if it is possible to display only a part of a layer based on other layer content - I mean, the second layer would play the role of a mask - like in Flash if you know it. Is it possible ? I ask for this with no idea how to achieve that - may be the concept of mask exists but it is not related to layers. When I make search about mask I only found answer about LayerMask but this is not the same thing.

Thank you

 

I think I have found out an answer in the forum :

http://forum.unity3d.com/threads/181605-Alpha-Mask-shader-Help