slab3d is a real-time virtual acoustic environment.
The smallest header-only GUI library(4 KLOC) for all platforms
Real-time interactive 3D graphics API for scientific simulations
Tao3D is a programming language for real-time interactive 3D
C/C++ library to add light and intuitive GUI to OpenGL and DX programs
A Lua and XML Graphical User Interface
A lightweight GUI library