After some more grey hair, I believe I talked the Local Weather package into working with live METAR data such that it is competitive with the default system. In some areas it performs worse (especially getting denser coverage of convective clouds right is a bit of a problem, it doesn't do time interpolation if a METAR station updates), in others better (it has a vertical model of the visibility and aloft winds, lateral interpolation of weather parameters, gets closer to the real sky appearance in comparison with webcam images,...). So - I am working towards a new version v1.0 soon.
In that context, I have two questions: 1) What is the best texture format for what I want to do? I've noticed that hires cloud textures take a long time to load and drain performance quite a bit. It seems Flightgear is loading a constant rate of texture pixels / time, which roughly says that I should not migrate to 2048x2048 cloud textures (although they look *really* impressive in tests) since the time to load a sky will increase by a factor four. In my current experience, loading new clouds is already a significant performance issue. What I have been wondering is the following: Currently I am using *.rgb textures. I have noticed that the filesize can be reduced by a factor 2 or so by going to *.png textures. However, what is the format which would most efficiently into the scenery? If *.png saves filespace at the expense of time, then there's no point in converting, but if png also loads a factor 2 faster, I would convert all texture sheets. I could of course run my own performance tests, but maybe someone simply knows? 2) What are the rules for loading live METAR? The context of this question is that I have the impression that if I would fly transatlantic (I have never tried, since I don't like the ocean view so much...) the METAR string would not change for a long time, and hence the weather would not change. That's not very realistic. On the other hand, I have a rather well-developed and plausible offline weather system, so I imagine that the controller switches from METAR to the offline system when the station is too far away and back when another station comes into range. Switching to the offline system while keeping all weather parameters plausible is not an issue - you just select an appropriate tile when the last METAR station has reached a distance d. But switching back to live weather is - because the offline system can't possibly guess correctly what the weather is on arrival when it switches over the Atlantic - so the matching has to be done carefully. To think this through, I'd like to understand how the weather fetching works - does it always pick the nearest station, even if that is 3000 miles away, or is there a distance cut, or some other criterion? Any help is appreciated! Thanks in advance, * Thorsten ------------------------------------------------------------------------------ Free Software Download: Index, Search & Analyze Logs and other IT data in Real-Time with Splunk. Collect, index and harness all the fast moving IT data generated by your applications, servers and devices whether physical, virtual or in the cloud. Deliver compliance at lower cost and gain new business insights. http://p.sf.net/sfu/splunk-dev2dev _______________________________________________ Flightgear-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/flightgear-devel
