A friend asked me for help with getting the sample here: http://www.mat.ucsb.edu/a.forbes/blog/?p=245 to work on the iPhone.
Since I had no experience with OpenGL ES 2 shaders, I thought it would be a good chance to get my hands dirty and learn something about it. I am still not an expert (far from it), so take it all with healthy skepticism.
This is an interim report, just to let you know the basics are working and provide with the sample code.
So the code is available here: http://iroth.net/prog/PingPong.zip
In addition to the article that was the inspiration of this, I could have not made this work without the help of the great tutorials of Ray Wenderlich and in particular this series of two:
One more thing - there seems to be some black triangle artifact in the upper left corner I still was unable to understand. If any of you find out - please comment below...
And while at it, here are some books that really help me get up to speed on iPhone game programming: