Curtis L. Olson writes:
>
> Stewart Andreason wrote:
>
> > Jim Wilson wrote:
> >
> >> There are a couple bugs or at least they were there a week or so
> >> ago. One is
> >> just a mapping typo where latitude goes into both latitude and
> >> altitude. The
> >> other is under linux the fg-root and fg-scenery parameters don't get
> >> saved and
> >> passed on to fgfs (no prefs.set done) unless you hit previous to display
> >> page[0] (the function that processes page[0] saves those strings).
> >
> >
> > Ah, is this why fgfs get stuck in a freezing loop, when I give
> > latitude and longitude parameters at the command line?
> >
> > (Tries a few more runs)
> > Ah! that's it. If I give a --lat that is less than the ground
> > elevation, it freezes in a loop. and ignores the --altitude parameter.
> >
> > I believe I reported this Jan.11, but had not figured out the exact
> > conditions that triggered it.
> > Thanks Jim.
> >
> > A serious bug.
>
>
> I can explain the bug to you. If you specify a lon/lat that lies on the
> *exact* border between two tiles (i.e. --lat=90 --lon=45) then at
> startup the ground intersection code can fail. This means that the
> scenery subsystem never returns a valid groud elevation. Now the
> problem is that the flight dynamics model *needs* to know the ground
> elevation before it can position the aircraft. Complicating the matter
> is that when the FDM is first initialized the tiled scenery loader may
> not have the current tile loaded yet. So the FDM doesn't know if it's
> in a dead lock state or if it just needs to wait a bit longer for the
> threaded tile loader to catch up.
>
> The solution would be to make the ground intersection code more robust
> to this boundary condition, but I believe that might be burried deep in
> plib.
This might help
hitlist.cxx
inline static bool IN_RANGE( sgdVec3 v, double radius ) {
- return ( sgdScalarProductVec3(v, v) < (radius*radius) );
+ return ( sgdScalarProductVec3(v, v) <= ((radius*radius) +FLT_EPSILON) );
}
but I don't see where setting the lat less then the ground elevation
has any bearing on this < this sounds more like a parsing error >
Norman
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