I am trying to create an app that allows the user to reveal a photo by rubbing off a masked photo layer with their finger (similar to the rub-off tickets you get in a gas station). I want to stack 2 images on top of each other with the top one completely hidden (masked) at start. Here is a basic diagram of what I am trying to accomplish:
I have been wading thru the GLPaint example code for the drawing portion, just not sure how to make the drawing view become a mask for an image below it.
Looking forward to the iPhone class in Denver in Jan. Thanks in advance for your help!