Hi Mathias, Mathias Fröhlich schrieb am 02.01.2007 10:51: > Hi, > > Great to have that interface now used! > I will only respond to the ground cache part. > > On Monday 01 January 2007 11:14, Maik Justus wrote: > >> The file groundcache.cxx.diff is only for osg and independent of the >> gear patch. It is a workaround for osg-groundcache bugs. It does not fix >> the cause, but with it the groundcache reports the correct material and >> correct ground height. Please commit to osg/head. >> > I do not think that ignoring all unknown ground types is the way to go. > > Of course not. But there are "invalid" triangles in the osg groundcache and they have *this* signature. (I do not discard all triangles with unknown ground). Without this method, you can not land on water. Give the gear-patch a try and try to land on water/ or just taxi in the water with and without my groundcache patch. > In general I am more for fixing bugs where they are rather than installing a > workaround. > Of course, but the groundcache returns wrong height now. Therefore I vote for applying this path up the bug being fixed. > Having that Unknown enumeration is just to tell the user (the FDM is the user > in this case) that we do currently not know anything about the kind of ground > we have under our wheels. > That groundcache is just thought as a lookup mechanism into the (mechanical) > environment of the aircraft. Having too much automagically /fixed/ in some > magic way may bite us later. > > >> >From that point of view it is just possible that we do not know anything >> >about >> > the type of ground we have a triangle in our hands. It is not guaranteed that > every geometry we have in the scenegraph has some ground type in this sense. > The FDM or say the user of that lookup mechanism just has to cope with that. > > I would prefer to store the ground type for the particular contact point and > reus The main problem is not the unknown type. The problem is, that inside the groundcache sometimes triangles are missing and no triangle is found. But for this your actual patch should be a workaround (not tested). The other problem are invalid triangles in the groundcache (and they have no material information). With them you get invalid ground-height information (probably the only occur, if parts of the aircraft are below the ground/sea-level (e.g. if you land on water). > e the last known one if you get an Unknown type from the ground cache. > The reason is: the ground cache query does not know about the last query near > that current point of interest. It just gets a point and returns something > about the mechanical properties below that point. > In contrast the class that is asking the ground cache for that information > might get needlessly unsteady when it gets something wired in this case. > > I also do not know what happens when we just omit some triangles. I fear that > we then just fall through solid ground that is just Unknown to the way the > ground cache currently decides the ground type. > No, not all "unknown" triangels are discarded. I have tested this on scenery objects with "unknown" material. Save landing is pssible on them. > I have now installed a patch that returns the material type of the triangle > that is used for the croase agl level in case we do only know that one. > Maik, that is like we have discussed offlist. > Thanks. > Anyway, I am working on a faster and more flexible replacement of the > groundcache anyway. > > Very good! > Greetings > > Mathias > > Maik
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