On Saturday 15 October 2005 20:54, [EMAIL PROTECTED] wrote:
> You know, I'd be happy to help do some of the taxiway work if a new format
> becomes available.  I've been trying to work with Taxidraw, but it's kind
> of difficult to work in because of the underlying format (I have no
> problems with Taxidraw itself.)  I find I spend a lot of time making sure
> the areas are in the correct place, all to make a curve that could've been
> described more easily with multiple points.
>
> I know there was some talk of extracting taxiways from the FAA's PDFs, but
> until that becomes available, a 'starter set' of airports in the new
> format might be a good idea.


I thought about the taxiway structure/format a while back.
I came to the conclusion that a raw polygon editor is about the only way 
you're going to be able to create taxiways properly.
One can use rectangular or bent taxiway sections but when you get to all the 
weird and wonderful taxiway layouts it's impossible to do with a generic 
taxiway structure. This is very apparent where taxiways intersect other 
taxiways, runways or aprons.

The only thing that made sense to me was a 2D CAD type app like TaxiDraw which 
can draw polygons of any shape and size. The tessellation stage can be done 
when building the scenery.
The only major problem I ran into was how does one handle markings and lines?
Having offset or floating polygon lines is a major trick with regards to 
z-buffer fighting. Texture based lines that are part of the taxiway textures 
need to be generated on the fly and consume huge amounts of VRAM due to their 
uniqueness so that's not a very good solution either.
Also cutting the lines into the taxiway polygons pushes the polygon count up 
horrendously.
I think we need to pick a solution that is going to work in the sim before we 
try to figure out what storage mechanism or format we are going to use.

Paul

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