> This feels like a moderately large issue to me, because out of the box, > we select basic weather, and hence we're going to get bug reports about > clouds not appearing. We could make basic weather drive the real > visibility based on altitude, but then we're moving away from 'basic > weather does what you set'. We could give basic weather sea-level and > altitude visibility and interpolate between them, which I guess is what > advanced weather does?
Well, the problem arises because a number of issues have so far been handled in a peculiar way: * Basic Weather 'out of the box' assumes, when driven with METAR, that the reported visibility has no altitude dependence (I think) - which isn't particularly realistic in the first place * clouds, unlike practically all other objects, do not really respect visibility the same way as other objects (they are fogged in the default rendering scheme at twice the nominal visibility, so a similar issue exists outside Atmospheric Light Scattering and clouds disappear before their rendering cutoff hits... * ... but Atmospheric Light scattering, unlike the default scheme, gives you always a rather clear skydome once you clear the ground haze layer as long as no extra high-altitude haze is declared, so in essence the visibility above the lowest layer certainly looks visually very high (this is intended since it gives you a realistic appearance of very clear air high up and the illusion of having several hundred km visibility) One could fix either of those: Changing aloft visibility in Basic Weather leads to memory issues. Not fading clouds leads to bad behaviour in low visibility. And fogging the skydome to agree with the set visibility leads to a completely unrealistic visual impression at high altitudes - 10 km forward visibility at airliner cruise altitude outside of cloud layers simply do not occur. So I'm not quite sure what the intended behaviour should be. Obviously, if you expect to see objects 70 km away with 10 km visibility set, there's something fishy with your expectation as well. And saying that you want to use visibility for memory management but otherwise have a realistic visual impression of objects 100 km away is also not quite a honest base expectation... > Suggestion: > rename cloud 'visibility' distance to 'draw distance' (since it's in > the rendering dialog anyway), to make it clear it's nothing to do with > weather / environment Sounds good to me - make that perhaps 'max. draw distance'. > in basic weather, have clouds ignore environment/visibility, and simply > > use draw distance (as before) > in advanced weather, cloud use the minimum of both, and get fogged, > with nice results in low vis situations. That's in essence asking to code a dependence on the active weather system into the shader, and that's something which imo smells like bad design. The shader shouldn't have to care how the properties which drive it are created. Can a Basic Weather user perhaps test if there is a substantial problem at all, i.e. if 3d clouds disappear as compared with expectations when running Basic Weather and Atmospheric Light Scattering? Maybe we're trying to come up with a fix for a rather theoretical issue... * Thorsten ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_feb _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
