TerraGear News and Updates

• January 5, 2005: Version 0.9.8 released.
  • World builder:
    • fixed a logical bug in the routine that strips out holes from a multi-contour polygon
  • Airport generator:
    • fixed a bug that caused threshold lighting to be omitted in some situations.
    • add airport surface bases for towers, windsocks, and beacons so these are never floating or buried.
    • much improved airport surface smoothing and fitting via a least squares nurbs approximation.
    • directly support Robin Peel's airport database format.
    • fix a bug that could put the same airport object in the final .stg file twice. This never affected rendering, but could significantly impact performance. This bug has been around for a while and we just noticed it now. Dohhh!

• July 30, 2004: Version 0.9.5 released.
  • World builder:
    • Added support for the FCC radio tower database.
    • Add support for SRTM terrain data
    • Split up many long edges to reduce artifacts in final scenery.
    • Much smarter/better/faster/higher quality terrain simplification algorithm.
    • Catch/fix/avoid a number of different degeneracies that could lead to odd artificants in the final scenery.
  • Airport generator:
    • Now handles displaced thresholds correctly.
    • *Much* better airport surface fitting to underlying terrain data. Employ a scheme that takes the average of critical surface points and produces a nurbs surface approximation to the original "noisy" terrain data.
    • Fixed "grassy" area in the middle of some runways.
    • Support for green taxiway centerline lighting.
    • Support for windsocks, towers, and rotating beacons.
    • Add support for Calvert-I/II approach lighting schemes.

• February 25, 2003: Version 0.0.5 released.
  • Added a tutorial for how to generate scenery.
  • Add support for UK OSBG36 coordinate systems (when calculating texture coordinates)
  • Updated dem libs to support z units of feet.
  • Added tguserdef, a utility for adding user-defined points, lines, and polygons to scenery. It uses the regular XML property format, which users can create easily in a text editor. See src/Prep/UserDef/sample.xml for examples.

  • Added support for generating accurate and correct runway and approach lighting.
  • Use wgs_84 math to layout runways and airports for increased accuracy. This also fixed problems with runway textures not matching up exactly.
  • Add a clearing around every runway so procedurally generated objects can't obstruct an approach

  • modified landcover code to borrow a cover type from an adjoining tile if it ends up as default -- this will help avoid resolution errors near rivers, urban areas, etc.
  • Fixed a bug in triangulating that was potentially overwriting other memory when creating the hole list to pass to the triangulator. This fixes a lot of glitches!
  • Don't generate a DEM tile when all elevations are zero. This should save about 70% worldwide with the GTOPO30 (less with the USGS DEM-3).

  • Added a utility to allow insertion of aerial photos into TerraGear scenery
  • libgpc.a renamed to libgenpolyclip.a to avoid a conflict with the gnu pascal compiler.
  • Updated/modernized automake/autoconf scripts
  • new library to support NIMA's Vector Product Format

  • Cygwin fixes
  • Irix fixes

• December 19, 2000: Version 0.0.4 released.
  • We now have a much more robust "point in a polygon" routine (i.e. finds a random point inside a polygon, but not inside a hole in that polygon.)
  • Removed the mat3.h dependencies.
  • Increased maximum area types to 128 for future expandability
  • Added road and railroad area types.
  • Added a new library for reading ArcInfo e00 files (DCW, GeoGratis).
  • Added a new prep util for creating textured polygons from e00 line data (i.e. for roads, railroads, streams, utility lines, etc.)
  • Added support for the USGS global land use / loand cover raster data base.
  • Better MSVC support.
  • Better Cygwin support.
  • Weight face normals by triangle area when calculating terrain node normals.
  • Screen for very small or degenerate triangles which could blow up our face normal calculations.
  • Fixed a bug which could cause a real mess in the scenery when an airport (or hole area) lay on top of a tile corner.
  • Clip all land use data to GSHHS land mask so that lower res data won't mess up our coast lines.
  • Add in support for GSHHS lakes, islands, and ponds.
  • Updated stats for parallel scenery build server.
  • Added a new option, "--cover", to fgfs-construct and fgfs-tools-client. The option takes an argument giving the location of the land-cover raster file; if it is not specified, land-cover is not built.
  • Increased max node count per tile to 4000.
  • Fixed a problem with dividing the tile up into land use areas (original scheme left really tiny slivers on the edges.)
  • Landcover/landuse changes by david megginson to group like chunks together into a single polygon.
  • Additional degeneracy and bad polygon screening.
  • Updates to ShapeDecode to handle NOAA landuse/cover shape files.
  • Tile constructor util will now accept an arbitrary list of directories to search for input data (so these don't have to be hardcoded.)
  • tracked down some "point in a contour" bugs. The terrain was stressing this code more that airports (which was where the code was developed.)
  • Built a generalized polygon tesselater out of Shewchuk's triangulator.
  • Added a routine to calculate the area of an arbitrary 3d triangle.
  • Bug fixes in the airport generator util.
  • Added a test program for the triangulator.
  • Added a print_tri_data() routine to dump complete triangulator data structure to screen.
  • Added a zero_triangulateio() routine to zero a struct before use.
  • Fixed a bug in Shewchuk's triangulator. This code does a lot of malloc()'ing of space, and in some cases blindly expects the results to be zero'd out, even though this may not be gauranteed. We now explicitely zero out these critical memory locations after it is malloc()'ed.
  • Added precision runway markings, switched how textures were applied (rotated them by 90 degrees.)
  • Updated runway texture layout in designator block.
  • Write out the AirportArea hole that has been segmented so it fits with the airport model that goes inside the hole in the terrain.
  • Handle too-short visual runways for now by converting them to simple runways.
  • Handle concrete textures as well as turf and dirt runways.
  • Added non-precision and visual runway markings.
  • Added code to chop up extra long line segments.

• April 6, 2000: Version 0.0.3 released.
  • Updated for SimGear-0.0.7 (or later)
  • Configuration and compilation fixes.

Last modified: 1/11/2005
Curtis L. Olson