[incr Tcl] is the most widely used O-O system for Tcl. The name is a play on C++, and [incr Tcl] provides a similar object model, including multiple inheritence and public and private classes and variables. Repos now http://core.tcl.tk/itcl and itk
TX Library is a tiny graphics library for Win32 written in C++.
TX Library is a tiny graphics library for Win32 written in C++. It is a small sandbox for the very beginners to help them to learn basic programming principles. The documentation is currently in Russian. More info here: http://storage.ded32.net.ru/Lib/TX/TXUpdate/Doc/HTML.ru, http://ded32.net.ru/news/2011-04-03-58, http://ded32.net.ru.
G3D is a commercial-grade C++ 3D engine. It is used in commercial games, research papers, military simulators, and university courses. G3D supports real-time rendering, off-line rendering like ray tracing, and general purpose computation on GPUs. As of January 16, 2018, SourceForge is again the home of the active repository for G3D.
A fast, unobtrusive and modern cross-platform GUI toolkit. Agar fully exploits hardware acceleration where available, but also supports simple frame-buffer interfaces. Agar is stand-alone and easily portable to new platforms and graphics systems.
Coin3D Windows GUI Library
SoWin is a library used with Coin3D Open Inventor for interfacing with the Win32 API on Microsoft Windows platforms.
GPU-accelerated image processing for java
blitz-image is a library to support extremely fast image processing in java, harnessing GPU acceleration via OpenCL. Although more features will be added in time, the initial focus is on very fast high-quality image resizing, including bicubic resizing (both upscale and downscale). The performance of a typical bicubic upscale operation is typically in the order of 10 times faster than via the standard AWT mechanism using RenderingHints.VALUE_INTERPOLATION_BICUBIC. The library depends on Aparapi (https://code.google.com/p/aparapi/). Any GPU supporting OpenCL should be supported (including low-end GPUs without double-precision fp support), and there is automatic fallback to pure java implementations for all operations in the event that there is no OpenCL support available. A high-level API allows for very easy use from AWT/Swing, whilst the low-level array-based API allows integration with any imaging framework (e.g. from Android or SWT).