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Next Generation Scenery

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Note  Some of these ideas are being already worked on, see Terragear roadmap, some other could be surpassed.


These are some ideas for new scenery and new scenery engine for FlightGear.

Status 2016

The idea is that we move away from vectoried landclasses and encode the information on landclasses in a raster-image (in my terminology a meta-texture). This has a couple of advantages:

  1. Generating an image seems to be much easier than vectorizing complex data structures
  2. By avoiding any mesh subdivisions due to landclasses, the mesh vertex count can be cut (drastically?)
  3. We get full control over how the transitions between landclasses look like
  4. We can easily fit man-made landclasses into the rest of the scenery in a plausible way
  5. Landclass editing by the end user can then be made with graphics software, no terragear runs are required[1]

Why?

We would like to show more detailed scenery that's visible farther away, for a better VFR experience all around. Specifically, more detail makes the near-ground experience more realistic, especially for helicopter or VFR flight; scenery that truly extends to the visible horizon would make high-altitude flight more interesting. In addition, it's fun to fly around a richly detailed world.

Disclaimer

Most of these items have been collected from various places without reasonable evaluation. Thus, they might simply represent peoples random ideas without any warranty about a) making sense in the given context nor b) aligning with the plans of those who are actually driving FlightGear's Scenery development. So, read this with a grain of salt ....

Ideas

  • Ability to dynamically enable/disable certain scenery features ([1])
  • Provide the foundation to eventually facilitate runtime-based creation of airport features (i.e. runways and taxiways), so that changes to the underlying data files (apt.dat.gz) could be immediately honored at runtime without having to recompile scenery tiles
  • Ability to cut in polygon models of airports. [2]
  • Ability to page terrain / textures so continuous flights around the world are still possible.
  • Ability to populate the world with arbitrary additional 3d objects. Note that our current ability to populate the world with random objects would not work with the new scheme. We'd need to completely overhaul that functionality to work in a photo texture draped, LOD terrain world.
  • Care should be taken with object vertical placement so the terrain LOD doesn't move the 3d objects up and down noticeable. And also so it doesn't noticeably bury objects or float objects when the terrain LOD changes.
  • I assume all the current 2d polygon data would go away since this would be better represented by the photo texture overlay anyway.
  • LOD algorithm/system (with adjustable radius for high and low end users) The current irregular grid mesh works but it's not very efficient and we could get much better framerates with a nice LOD system. Alternatively much higher elevation resolution with similar frame rates.
  • Texture overlays - FG scenery engine does the chopping and texture coord generation. (I won't go into details but this would greatly simplify LOD algorithms)
  • The ability to drape the textures at differing resolutions at different locations in the scenery. (ie. higher res data immediately adjacent to airports where the pilot is generally closer to the ground and to give good definition on final approach).
  • Some sort of fix or workaround for the stretched-textures-on-cliff faces problem that draped textures suffer from in mountainous regions - possibly the ability to cut in textured polygons on steep faces.
  • Ability to deform objects upon impact[3]

Data sources

Here is a list of possible data sources for better scenery.

Elevation data

  • http://www.viewfinderpanoramas.org/dem3.html
  • SRTM Data - 30m resolution for North America, 90m for most other world. Data goes up to about 60 degrees north and 56 degrees south. Commercial/GPL use is restricted.
  • ASTER GDEM Aster data, 30m resolution for the whole world, from 83 degrees north to 83 degrees south. License is limited, might be able to get the data and use, but redistribute with non-GPL license.
  • Mountain data Personal work of Jonathan for filling&fixing SRTM data for mountain areas. There can even data be found for regions not covered by SRTM or ASTER, like Antarctica. Mostly 90m resolution, but some areas are 30m. Also has some data for north eurasia not available in SRTM. Data should be free to use, but not sure about the GPL compatibility, this might depend on the original data sources.

Shapefile data

Some sources for shapefiles, some of these are already available, the ones with links might not be yet.

Photo data

1rightarrow.png See Photoscenery for the main article about this subject.

To be defined, so this section is reserved for acquiring free high resolution images for it. See also the article on Brest photorealistic scenery.

Related mailing list discussions

Related Projects/Efforts

  • Thorsten Renk  (Jun 3rd, 2016).  [Flightgear-devel] Experimental new scenery format - help required .