Here are some results with GodRays, ported from
Full size: http://s14.directupload.net/images/140105/p9pmsgti.jpg
And here’s a screen how it works:
Full size: http://s14.directupload.net/images/140105/srby72aq.jpg
I’ll try to make a small demo app soon, but it’s difficult because it needs a derefered rendering pipeline with position reconstruction.