On 24/01/2005 at 21:17 Durk Talsma wrote: > >What I am really looking for is a hint where I can find the code in >FlightGear
Hi Durk, I obtain ground elevation for taxiing AI traffic in AILocalTraffic.cxx, lines 1569 - 1602 (or thereabouts). Note that this is not a cheap operation, and you should only do it for traffic in a location which already has a tile loaded - otherwise it triggers tile loading, resets the scenery cache to the wrong location, and probably has other undesirable side effects as well. I'm still not entirely sure how all this works, but when I dug into it once it seems that the way I do it can mess with the tile cache unless I'm not determining elevation for the tile currently at the center of the cache (or something like that). FG could really do with a clear, unambiguous, documentated elevation API of the GetGroundElevation(lat, lon) type that would not mess with the tile cache, and not bother giving accurate elevations for unloaded tiles. Until then, a lot of subsystem writers have / will spend a significant amount of time figuring out how to get a ground elev, and wondering what they're breaking whilst doing it. As Curt says, regardless of the above, ground elev will always be expensive - if the airport has a node arc layout you could dynamically cache lookups for following traffic, interpolate between reasonable differences, etc, etc. Cheers - Dave This message has been checked for viruses but the contents of an attachment may still contain software viruses, which could damage your computer system: you are advised to perform your own checks. Email communications with the University of Nottingham may be monitored as permitted by UK legislation. _______________________________________________ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
