On Sunday, July 13, 2003, at 08:25 pm, David Megginson wrote:
A new bridge, the famoust, is in CVS : http://perso.wanadoo.fr/frbouvi/flightsim/fgfs-golden-gate-01.png
Gorgeous! I've been waiting for this one for a long time -- Marin County looked so lonely sitting there with no link to SF.
Yes, it looks great. However, it has unearthed a *serious* (ahem) issue with the collision detection logic.
You can't fly under the bridge. I tried it once, in the airbus, and figured i'd clipped the tail on the road deck, but I just tried again with the 747, and was definitely well clear this time.
Now, I know it's not terribly vital for serious flying that this work, but doesn't this also imply, for example, that we can't taxi into a hangar or under part of a terminal building? No doubt there are other legitimate, necessary cases where we need world geometry and aircraft geometry to interact like this (passenger jetway bridges? aircraft carrier lifts?)
Another thing to consider is the flip-side - being able to taxi *on* bridges, like the taxiway at Amsterdam Schipol which crosses a motorway, it's very strange looking out the passenger window and seeing cars passing underneath.
I don't know how much collision detection SSG handles, but the way I'd (naiively) imagine this working is to do polygon-accurate collision checking with every static object who's bounding sphere intersects that of the aircraft model (with some margin to be safe). That should keep the cost very low, since such close interactions will occur very infrequently, but give full, geometry level accuracy of collision response for stunt flying, ground taxiing and StupidBehaviour(TM) of the kind I just attempted under the bridge.
Anyway, that's enough nit-picking. Keep up the fantastic work, Frederic.
H&H James
-- That which does not kill me has poor aim
_______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
