The OpenSceneGraph is an open source cross platform graphics toolkit
for the development of high performance graphics applications such as
flight simulators, games, virtual reality and scientific
visualization.  Based around the concept of a scene graph, it provides
an object oriented framework on top of OpenGL freeing the developer
from implementing and optimizing low level graphics calls, and
provides many additional utilities for rapid development of graphics
applications.

ffmpeg, gdal and gtkglext are optional dependencies.
