Light shafts

In my holidays I'm trying new techniques for my terrain engine. Unfortunately, in my screen space terrain implementations, the well-known artifact of "vertex swimming" appears and it's very noticiable :|

I think that I can reuse the technique in order to code a cool screen space water effect in the near future.

For now, I'd been added the "Game Programming Gems 6" terrain technique (very simple, pretty fast, and without any pre-calculation), light shafts (but the effect needs a radial blur), and particle billboards for cloud rendering.