Came across Cinder recently while doing other things.
Cinder is an open source C++ library which is useful when programming applications with requirements for graphics, audio, video, networking, image processing and computational geometry.
It is cross-platform and the same code should work across a variety of platforms including Mac OS X, Windows and hardware such as the iPhone and iPad. Cinder will also make use of the native capabilities of a platform and minimises the need for 3rd party libraries.
More details at
[Current version is v0.8.4 released on May 17, 2012]