I am an iOS developer but I'm new to cocos2d. I'm working on new game, I use Kobold2D, have cocos2d installed too, and I want to make this effect:
I know how is done with Flash, but can't make it with Kobold2D. There's 2 images with the same size: one is a low-res image for the background and the second is a hi-res over the first one. When the "reticle" mask moves, it reveals the second image inside the circle and the background is visible outside only. I googled with no success, saw some Ray Wenderlich projects they weren't helpful.