ColDet 3D Collision Detection Library is a library that provides collision detection for generic polyhedra. Its purpose is mainly for 3D games where accurate detection is needed between two non-simple objects. It also includes a fast multi-object system that quickly prunes the space of pairs to be checked, and additional support functions such as tests for ray picking.
coastal-qt is a small collection of Qt 4/5 desktop applications built around a small Qt extension library. The library mostly focuses on missing features and services like OSD desktop notifications (with DBUS bindings) and offers some convenience classes for Qt. The current applications include a GUI man page viewer, a search tool, and a desktop user notification service daemon with multicast chat.
fuzzylite is a fuzzy logic control library. Its goal is to allow you to easily create fuzzy logic controllers in a few steps utilizing object-oriented programming without requiring any third-party libraries. qtfuzzylite is a Qt-based GUI for fuzzylite. Its goal is to allow you to visually design your fuzzylite controllers and interact with them in real time.