A conversion and compression tool for the KTX image format. See more here http://www.khronos.org/opengles/sdk/tools/KTX/file_format_spec/
It supports PPM input format without any external dependency. But also TIFF, PNG and JPG as a standalone implementations. It also has an ImageMagick implementation (that suppports all major file formats).
If you want to use imagemagick set the cmake option WITH-IMAGEMAGICK to true like this:
cmake ./ -DWITH-IMAGEMAGICK=true
Be aware that this will disable all other "WITH" options as imagemagick already implement those formats and they're not needed.
To enable multithreading set WITH-TBB to true like this:
cmake ./ -DWITH-TBB=true
With this the compression is reduced by the number of your CPU cores. Is recommended to have this enabled but it's not required.
To generate a cube map texture type this command ktxtool face1.jpg,face2.jpg,face3.jpg,face4.jpg,face5.jpg,face6.jpg
Only RGB8 and RGBA8 is supported either raw or compressed, as for compression goes only ETC1 is implemented. I made this tool for mobile development so even if this tool is far from complete it could be used for production already if your usage match mine.
PNG and JPG input formats are expected before v0.2.0
S3TC compression is expected before v0.2.0