RenderDoc is a stand-alone graphics debugging tool
Everything you need to build and deploy scalable realtime 3D apps
Orx: Portable Game Engine
Delphi : VRCalc++ OOSL & + (Paged List, TextEditor, VRAstroVision ...)
Cinema Enters Game Console
ZED OS the clone of Windows XP
Build Cross-platform Applications
Highly customizable library for procedural world generation
3D .NET engine for Windows, Linux, Mac
C-Lesh is a game programming language for 2D games.
A cross-platform OpenGL based lightweight scenegraph library
A powerful cross-platform and open-source 3-D rendering engine.
Java based Open source Voxel Engine for RTS games