Now I'll try to use an other technique with rings, and add a volumétric fog into it, with a clouds layer... Here is my first try of "cloudy rings":
I've used functions tree to clamp the clouds on Y axis... Two conditionnal scalars (-500 to infinite and 500 to infinite are multiplied) (I'm sure that there is a simplier solution, but I don't find it). I use the result to blend a rings image map. It's not bad, but not perfect, and I have several problems:
- Clouds calculating is really long, so I must reduce planet size (to 50000), that way the clouds depth is not too big.
- With 760 samples, my clouds softness isn't good. There is some noise. I don't knows why... So there is a problem somewhere, maybe the image map shader.
- My function tree just do black or white value. No grey value, so no gradient on altitude, and that's not good. Schematically I want white value (1) on y=0, black value (0) on y=1, and grey value (0.5) on y=0.5.
- If I can just use functions to draw my rings (by random seed), and delete the image map shader, it would be better. Is there a way to do that (radial gradient with function noise)?
So there is a lot of work yet. If somebody want to take a look,
the scene is here.
Another thing: Can we use blending (or fake blending) on an atmosphere? It would be cool, to do polar aurora (for example), or the magnetic fields of a sun.
Last time I've tried that I've simulated altitude gradient density with several clouds layers... Was good for a ground view... But at the scale of a planet, see from space... As there is already altitude gradient values in atmosphere shader, use it could be fun.
Or, maybe, I can use a gradient density function, as blending, on a clouds shader. But, I guess, the render time will be very long...
nb : Please excuse my english.
