Revolution Engine is the very First homebrew 3D Game Engine for Wii. It is directly based on GX without any GL wrapper or anything similar. Natively designed for the Wii, this engine is probably capable of generating the best homebrew graphics ever seen on this game console.

Release notes:

More than a year later, a new version is released. With this version, the engine has been completely re-written and ported from C to C++. For the first time, this version of the engine comes with precompiled demos with source code that will help people learn how to use it faster. This version of the engine has been designed with flexibility and extensibility in mind. Users can create their own model format loaders and renderers, they’re own materials etc…and they will be full compatible with the core engine.

http://wiibrew.org/wiki/Revolution_Engine