Re: [Plib-users] BGL Loader

[John <ndc...@mx...>]

Steve Baker wrote:

> John wrote:
> >
> > Steve Baker wrote:
> >
> > > John wrote:
> > > >
> > > > Do we have any BGL loader project running now?
> > >
> > > What is BGL?  It's not a TLA that I'm familiar with...which
> > > means that there almost certainly isn't a BGL loader in the
> > > works right now.
> > >
> >
> > M$FS 3D scenery usually use .bgl files to present buildings.
>
> Ah - OK.
>
> > I am also a FGFS user. If we can have a BGL file loader in ppe, we
> > can convert M$SFS secnery to objects that FG accepts. One problem I
> > am not sure is that how thousands of BGL objects be rendered in FG.
>
> They would need to be referenced by the terrain files I would think.
>
> Generally, there are three kinds of features you need to think about:
>
>   1) Scattered objects - like trees, farmhouses, barns.
>      The models are generic and would be scattered randomly but
>      in 'typical' densities depending on what part of the world
>      you are in, the slope and nature of the terrain, etc.
>      (The scattering could either be in realtime - or performed
>      by the offline tools).
>
>   2) Generic features like bridges, radio towers and such that are
>      placed at very specific 'real world' locations by your tools.
>      You may also need to pick the right version of the library model
>      for the span of a bridge (to make it fit the width of the river
>      it's crossing) or the exact height of a radio tower.
>
>   3) Specifically modelled landmarks...things like the Eiffel Tower of
>      which there is uniquely only on on the planet and hence cannot
>      reasonably be pre-loaded into the simulator - but instead need to
>      be pulled in along with the terrain tile they belong to.
>
> Airport buildings tend to be type (2) or type (3).
>
> Anyway - the exact mechanism to implement this placement would be
> a question for Curt (who listens to this list).
>
> EIther way, having a PLIB BGL loader (and writer) would be an excellent
> starting point.

    After talking to some MSFS developer, they told me there maybe already
a scasm->dxf conveter (otherwise it's "dxf->scasm" converter instead of
"scasm->dxf") and  possiblely in Window$ only. Too bad I don't have a
Window$.
    However they told me that only about a dozen out of 200 BGL commands
are involved in polygon drawing. I think this is expected because(?) BGL
files might contain more information about "positioning" those buildings
than the 3D models of those buildings.
    Anyway, I need to run the Window$ program without using Window$, and
figure out how to extract positioning information from BGLs'. Does this
sounds right?

John Tsao