After making some ground observations yesterday, I've been thinking about how to render haze-like, rather structureless clouds - like in the following pics:
http://www.clouds-online.com/cloud_atlas/cirrostratus/images/cirrostratus_nebulosus.htm http://www.clouds-online.com/cloud_atlas/altostratus/images/altostratus_translucidus_4.htm In reality, these are very extended layers of very low density - basically several hundred meters of faint haze. That means it's not very realistic to treat them with a 2d layer. It's also very difficult to find a 3d approach for them, as the individual cloudlets would need to be huge to get the thick layer structure with finite rendering time, and faint translucent clouds are not easily done as models in any case. But I've been thinking that the combination of sky dome and default terrain shader does a very good job in simulating low visibility, i.e. ground haze. So, might not the sky dome alone (since you'd usually look up into the cloud no need to modify terrain) do an equally good job in simulating sky haze? Basically, what I have in mind is an additional property which allows to specify the amount of high altitude haze (i.e. the 'target whiteness' of the sky directly above) in addition to the visibility. The cloud model for such nebulous cirrostratus would then simply adjust target whiteness and visibility in a (yet to determine) way as one increases altitude that the sky above is haze from below, then as the cloud is reached the horizontal visibility deteriorates somewhat but they sky becomes more blue, and finally above the cloud the original sky color given altitude is recovered. I have the feeling that this just might work to render clouds which really are no well-defined objects, but rather a very diffuse high altitude haze. Would it be difficult to insert such an option into the sky dome code, maybe as with the light saturation? I think that worked out very well to simulate the darkening in heavy rain... * Thorsten ------------------------------------------------------------------------------ WhatsUp Gold - Download Free Network Management Software The most intuitive, comprehensive, and cost-effective network management toolset available today. Delivers lowest initial acquisition cost and overall TCO of any competing solution. http://p.sf.net/sfu/whatsupgold-sd _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
