Hey, thanks those are some useful resources.
I have seen the microsoft flight simulator pdf, but that's more for flying through the clouds, so I'm looking for a more 2D approach that renders a cloud layer. After a bit of investigating, I feel like I need to do more atmospheric scattering in the lighting, which should lead to an improvement in the look. I'm also familiar with the vterrain page.
Mostly looking for information on the lighting of the cloud layer, my previous shot was after an afternoons worth of work so there's much to improve!
My sky does have dynamic time of day (based on http://www.cs.utah.edu/~shirley/papers/sunsky/sunsky.pdf), using a procedural cube-map I generate each frame based on the sun position. And, although I think my sky looks nice enough, I think it's probably a little too much atm (performance is fine) it just feels like I could get a similar look with a 2D texture but I consider that part unimportant at the moment (I'm happy with the way it looks, but I think a simpler implementation may be better).
These days this is probably the best paper I've seen on sky rendering: http://www.hpi.uni-potsdam.de/fileadmin/hpi/FG_Doellner/publications/2012/MED12/paper_1056_cr.pdf
That's a nice pdf I haven't seen before thanks, my night cycle is poor atm so it will be nice to read through that.
I've been busy with the holiday season so haven't done too much on the clouds since, though I will be back on that soon. Currently writing a simple ray-trace so I can look at the cloud math without worrying on perforrmance too much, then see what I can translate back into shader code once I grasp it fully.
I'll put some screenshots here (again, the engine is mostly for research than any particular goal at the moment), just for fun there is a lot for me left to do.
Thanks again for the links I will look through them.