RenderDoc is a stand-alone graphics debugging tool
Display, convert, and edit raster image and vector image files
3D Engine c++
GLScene Engine for Delphi & C++Builder VCL Windows 32/64
Lightweight and modular C++11 graphics middleware for data and games
Character animation system for games and simulations.
High performance image processing library in C++
PixelLight is a cross-platform application framework