VTP Implementation - Other Potential Libraries

• it may make sense to build on many more libraries in the future, but they should be portable and at least free for non-commercial use, if not more open

Anti-aliased rendering

• Anti-Grain Geometry (AGG)
  • free license, portable, high-quality anti-aliasing
• Cairo: A Vector Graphics Library
  • possible alternative to AGG for rendering anti-aliased polygons?
• Malte Clasen blog post says: "If you just need vector graphics, use Cairo. If you need them fast and if you are willing to trade a high level interface and a good documentation for speed, go for Anti-Grain. Btw, I didn’t notice any difference in quality on the first sight, both produce very good looking images."

Image convolution

• ImageMagick
  • a huge amount of image functionality, reportedly including image convolution, which might free us from BExtractor's dependency on IPL

Reading ZIP files

• Info-ZIP's UnZip
  • totally portable, license freer than LGPL
  • tried to use it; unfortunately had great trouble getting it to build
• Minizip (Zip/UnZip) from Gilles Vollant
  • looks nice, but it's also already built into wxWindows, so it may make more sense just to use that one

Generating contours from a grid

• A C++ implementation of an improved contour plotting algorithm, by Jonathan de Halleux
  • it looks nice and simple to use, but the demo program that comes with it crashes on recalculation

Polygon triangulation

• see Triangulation of Simple Polygons

Other

• libjpeg-turbo
  • Claims to be 2-4x as fast as the regular libjpeg.  If JPEG read/write speed ever proves to be a bottleneck, this is worth investigating.
• GEOS
  • a C++ port of the Java Topology Suite (JTS)
  • includes all the OpenGIS "Simple Features for SQL" spatial predicate functions and spatial operators
  • the license "hasn't been decided yet" - likely GPL or LGPL
• GPS3D
  • a set of 100% free open-source utilities to access a GPS device from a Linux/Win32 box
  • "Tested with a Magellan GPS 315, and has never been tested with any other GPS devices out there. If you own a Garmin, you can either get it to spit NMEA compatible stuff, or change the code to handle it."
• VRPN - Virtual Reality Peripheral Network
  • a sort-of industry standard for virtual reality hardware support, including a wide variety of trackers
• OSSIM - Open Source Software Image Map
  • a Remote Sensing/Image Processing/GIS package
  • portable, and powerful, but quite huge - it would be a giant dependency to add, and it duplicates a great deal of what is already available in the VTP and existing dependencies, e.g. GDAL
• SDL - the Simple DirectMedia Layer
  • provides portable audio, video, events, threads, kb & mouse i/o, CDROM access, and reportedly works well with OpenGL
  • the VTP distro now includes an example (sdlSimple) of how SDL works together nicely with vtlib
• MAM/VRS
  • two open-source APIs (high-level/low-level) for building 3D visualization applications
  • reads formats: 3DS, BMP, JPEG, PNG, PPM, SGI
• SEDRIS Coordinate System API
  • SEDRIS is the Synthetic Environment Data Repository and Interchange Specification
  • currently used by the SRI digital earth group
  • might be faster or more robust than the other other options, i.e. GCTPC and PROJ.4
• XFrogLib - a library for constructing geometry from xfrog plant descriptions
  • depends on permission from Greenworks
• cal3d
  • a skeletal based 3D character animation library, C++, portable
  • could be used by vtlib for articulated people/animals
• CWXML
  • fast reader and writer for XML and GML, including BXML (binary XML)
• Carworld
  • open source example of Car Simulation, using the Open Dynamics Engine (ODE)

Libraries Evaluated, but not used:

• CDBFile
  • GPL C++ library for reading DBF files, an important part of ESRI Shape files
  • available from numerous locations e.g. cdbfile.zip at the Simtel archive
  • fortunately, doesn't seem to be needed, since other libraries like Shapelib which read Shape files, also provide support for the DBF files
• QT - portable GUI library
  • looked into as replacement for wxWidgets/MFC in the VTP apps, but it does not support free software under Win32 - the free version for non-commercial use is only for Linux
• PLIB - Steve's Portable Game Library
  • provides GUI widgets, sound, matrix/vector math, and the simple scene graph library (SSG)
  • unfortunately, despite a great deal of time spent attempting to port vtlib to SSG, it did not produce a usable port, and the author has been too busy to provide support
• CrystalSpace, Open Inventor
  • other open-source portable 3D APIs
  • CS was too large and complex to be a layer under vtlib, preventing a modular library design
  • Open Inventor did not support Win32
• squish - DXT Compression Library
  • tried version 1.2, with MSVC7.1.  Many problems were encountered.  Build warnings were flagged as errors. Using kColourClusterFit resulted in some textures taking forever to compress, debugger shows buggy values inside the library.  Using kColourRangeFit, debugger reports stack corruption.
  • Eventually got it compiled, and it remains an optional library
    Time in seconds to compress a tileset:

    	Hawaii2k/4x4/512/3	Oahu/9x9/512/3
    OpenGL:	2.0	10.3
    Squish fast:	2.9	19.9
    Squish slow:	17.0	124.2