I have made good progress with the lighting. I have not really worked on day/night cycle or any of the other features you would want for a full fledged “Sky system.” I feel like that is pretty game specific, and I was hoping to get this out as one shader, more of a starting point than something that is trying to do too much.
For example, the side by side below is one simple tweek to the blending in the shader and yields very different results. Neither of these have phase applied either. Some games combine the phase function at several different eccentricities to get forward scatter light to get a certain look. I think this might be better to comment in the shader, but not apply. It really depends on the game.
So at this point, the lighting model is pretty much done. I am finishing up intercloud shadows now but as expected the performance is not great (like 55ms per frame not great). The results look pretty good to me though, so I would like to ask for suggestions/help with optimization, as there may be some things I can do pretty easily in jMonkey.
In one of the documents I linked, they mention building a full frame over several frames. I believe they use two render targets for this and flip them as they build the full view, but I am not 100% sure on that. The video I linked appears to render the screen in segments for performance. This I would assume was done with a compute shader. Does anyone have input or a suggestion for what might be able to be done without a compute shader? I am leaning towards the render target.