RE: [Flightgear-devel] If everybody had an ocean...

[Curtis L. O. <cu...@fl...>]

David Megginson writes:
> Since roads are much longer than runways, they'll have to be segmented
> fairly frequently, especially for US scenery using the DEM-3 data.
> Even a 1km segment of straight road might go up and down a couple of
> hills, and some segments can be 10 or 20km or more.  Knowing something
> about the underlying DEM might help

We might be able to come up with a length that works reasonably well
in most situations.  I'm guess that roads that go through complex
terrain would generally be curvier and thus have more segmentation
built in automatically.

> That won't matter anyway.  Like airports, roads (etc.) would have to
> be saved as separate objects, with holes passed to the regular polygon
> clipping routines.  The holes shouldn't get any LOD nodes in the first
> place.

Yup ...

> As with the airports, the other polygons would be clipped against the
> holes left for the roads, while the roads would be loaded from
> separate files.

Yup ...

> This would be done earlier, during the prep stage (as with airports),
> and the objects would simply be copied during the scenery-generation
> stage.
> 
> Thanks for volunteering.  The nice part of this approach would be the
> ability to use aligned textures for roads and railroads (i.e. pavement
> with a yellow line in the middle and gravel shoulders rather than just
> grey rectangles).  I don't think I want to write the code, though.

Give me a couple years and I'll get to it. :-)

Curt.
-- 
Curtis Olson   Human Factors Research Lab       FlightGear Project
Twin Cities    cu...@hf...                cu...@fl...
Minnesota      http://www.menet.umn.edu/~curt   http://www.flightgear.org