For a long time, I’ve found ATI’s (now AMD’s) CubeMapGen library to be an indispensable tool for creating prefiltered environment maps (important for physically based shading). Many older GPUs (all the ones in current consoles) do not filter across cube faces. CubeMapGen solves this problem and others – details can be found in a GDC presentation and a SIGGRAPH sketch, both from 2005.

Support for CubeMapGen has been spotty for the last few years, and a while ago AMD officially declared its end of life. Since then I’ve been wondering when AMD would open-source this important tool – there is a good precedent in NVIDIA texture tools, which has been open source for several years now.

Speaking of NVIDIA texture tools, a comment on its Google Code website just let me know that AMD has released source to CubeMapGen. A link to the source for version 1.4 can be found on the bottom of the CubeMapGen page. Note that this does not include the DXT compression part of the edge fixup (which was a pretty nifty feature – hopefully someone will reimplement it now that the library is open source).

Looking at the license doc in the zip file, the license appears to be a modified BSD license. This is excellent news – tools like this are far more useful when source is available. Perhaps someone should host the code on Google Code or github, to make it easier to add future improvements – or maybe it could be folded into the nvidia_texture_tools code base (if the license allows).