AutoGen scenery for FlightGear

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Autogen Scenery

Started in	11/2013
Description	Improved autogen support for FlightGear using OSM data
Contributor(s)	radi, vanosten, Soitanen, portreekid
Status	Under active development as of 02/2016
Topic branches:
$FG_SRC	https://gitlab.com/osm2city/osm2city/
fgdata	https://gitlab.com/osm2city/osm2city-data/

See also Random Buildings

Use the GNU GPL PixelCity project to create autogen scenery support for FlightGear, to dynamically create cities for populating the FlightGear scenery procedurally.

PixelCity is at the moment C++ code that uses pure OpenGL with a fixed rendering pipeline (i.e. no shaders).

There is a blog column providing in-depth details about the implementation of PixelCity: http://www.shamusyoung.com/twentysidedtale/?p=2940

To view a demo video of PixelCity, please see: http://www.youtube.com/watch?v=-d2-PtK4F6Y

A list of known issues is available at: http://code.google.com/p/pixelcity/updates/list

Opinions

• It is excellent not just in the rendering but the generation of the buildings, traffic effects etc. [1]
• This technique could make a hell of a difference in things like flight simulator programs, some of the manually built cities in them are just awful, this looks way better and is procedurally driven? any flightsim developer worth their nuts should be begging you for this code. [2]
• This should be added to FlightGear, an open source flight simulator. Only 50 hours in the making? I salute. [3]
• It really looks cool from the distance and close up.

Code

Official repositories:

• PixelCity at Google code
• PixelCity source code at github

Originally, PixelCity only built on Windows, but there are now a number of ports available:

• PixelCity (Linux)
• PixelCity port for Linux
• Another PixelCity Linux port

• PixelCity Mac OSX port
• Another Mac OSX port
• cmake based PixelCity build

Porting

• Implementing it into FlightGear requires porting the OpenGL calls to be OpenSceneGraph compatible, probably by implementing osgDrawable.
• The current implementation only shows night-time views, so this has to be tweaked, too.
• Another issue to take care of is interaction with existing scenery models, so the generated buildings do not interfere with our scenery models.
• The same is true for our landcover, roads and elevation data.
• Definitely worth some thinking. Probably as a google summer of code GSoC project?
• Perhaps something using blended cities?
• You could input a street map and it would only build buildings in the lots, not on the roads.
• Now, maybe combine that with open street map or something?
• Also, you could then just load it fairly normally into flightgear.
• Instead of downloading the building, it could be an option to download the files needed to make it and do it yourself.
• It would probably make sense to start an OSG port, so that the port is not FlightGear specific, but could be used by other OSG based projects (pretty much like OSGOcean, OSGTerrain etc)

With my python coding for OSM buildings in FG coming along nicely, I recently thought about creating semi-generic bridges. Is anyone else working on this? Or is anyone aware of an open source procedural bridge generator? Searching the net mostly turned out stuff for Houdini etc. —

Related content

Forum topics

• [Proposal] Autogen Cities using PixelCity topic on the forum (July 2010-May 2012)
• Re: Procedural buildings in OSM before part of Scenery post on the forum (September 2012)

Developer mailing list

• [Flightgear-devel] Upcoming Random Buildings changes (September 2013)