Abe nous apporta ses lumieres ainsi en ce 2004/04/17 23:29... :

> Continuing with the idea of shading a 2D texture to appear 3D.
>
> The trick seems to be to pick a point and march along a ray on the sky 
> plane toward the sun, sampling the 2D cloud texture along the way. 
> Based  on the samples collected, the point is assigned a degree of 
> "illumination" or brightness.
>
> I have a lot of fun with the idea, but so far my implementation is no 
> where near as elegant as I think it could be. Come to think of it, 
> writing it as a shader for POVman might be smoother.
>
> What's here is a set of layered textures which have the following 
> tasks (in order): sky color, sun and sun glow, base cloud color, cloud 
> illumination, haze, flare.
>
> What's not here is any attempt at implementing pronounced forward 
> scattering or multiple scattering effects. There is also no 
> comprehensive model which steers the different colors - they are all 
> set individually through trial and error (and will probably still be 
> off when I get a chance to look at them on a CRT!).
>
> Abe
>
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The big one look like an actual photo, I've seen real clouds loking the 
same. Very realistic. I'm using a CTR.

Alain

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