plz let me know how to use sprite mask?

I want This image ->http://imgur.com/a/Q9sUC

masking(cutoff) like this ->http://imgur.com/a/yrdQC

both images are based on Sprite renderer with material. and It will make prefab.

I dont wanna use UI Canvas.. but unity mask component is based Canvas renderer. (As far as i know.)

http://u3d.as/bzJ How you think this asset? It is useful?

plz help me T_T