this is the web site:AntTweakBar is a small and easy-to-use C/C++ library that allows programmers to quickly add light and intuitive graphical user interface into OpenGL and DirectX based graphic programs to interactively tweak them.
Program variables can be linked to a graphical control that allows users to modify them. Thus, parameters exposed by programmers can be easily modified. They are displayed into the graphical application through one or more embeded windows called tweak bars.
http://www.antisphere.com/Wiki/tools:anttweakbar


It is released under the zlib/libpng license.