How to make (or event fake) ripple animation on iPhone, iPad by UIView!

I'm doing an app on iPad, and I wanna make a ripple effect in a background image, just the ripple animation for surface of water. Flash can solve t开发者_StackOverflowhis issue easily, but it's not available on iPad. Does anyone know something about this?

With iOS 5, Apple now has a sample project called GLCameraRipple that lets you tap/draw on the screen to create animated water ripples over incoming video from the camera... a nice example of using OpenGL ES 2.0 and GLKit.