BRL-CAD is a powerful constructive solid geometry solid modeling system that includes an interactive geometry editor, ray-tracing support for rendering and geometric analysis, path-tracing for realistic image synthesis, network distributed framebuffer support, and image and signal-processing tools.
BZFlag is a 3D, multiplayer, tank battle zone, capture the flag game that pits players against each other in a networked environment. It runs on Windows 95/98/NT/2000, Linux, MacOS 10.x, Irix, Solaris, and others. An OpenGL accelerator is highly recommended, but it is playable with 3D in software.
PLIB is a set of libraries to write games and other realtime interactive applications that are 100% portable across a wide range of hardware and operating systems. It's used by Majik3D, FlightGear, and others, and includes libraries for GUI widgets, sound replay, geometry, scene graph, joystick, and fonts/text.
libGlass is a scalable set of components that can be used by applications to perform distributed computing. Applications are built by reusing the available components as needed. One of the major goals of Glass is to be a user-friendly framework, not only suitable for new applications, but also for legacy code. This is an important feature, as most available solutions for distributed computing require a substantial amount of rewrite of legacy code.
The LibXDiff library implements basic and yet complete functionalities to create file differences/patches to both binary and text files. It uses memory files as file abstraction to achieve both performance and portability. For binary files, it implements both (with some modification) the algorithm described in "File System Support for Delta Compression" by Joshua P. MacDonald and the algorithm described in "Fingerprinting By Random Polynomials" by Michael O. Rabin. For text files, it follows directives described in "An O(ND) Difference Algorithm and Its Variations" by Eugene W. Myers. Memory files used by the library are basically a collection of buffers that store the file content.
OpenSG is an Open Source scenegraph system. Its design goals include high performance, multithread-safe data handling, high flexibility, extensibility, and portability to Irix, Linux, and Windows. A number of computer graphics research institutions are actively working on moving the system beyond the state of the art to include features like clustering, subdivision surfaces, occlusion culling, and more.