@Bighead: just uploaded a new version can you please test that textures with custom mips work as intended?
@embrez: for the error message it seems that you are on the wrong folder, you should download the files, enter the folder of the repository create a build folder enter that folder and then execute that command.
@embrez: for the error message it seems that you are on the wrong folder, you should download the files, enter the folder of the repository create a build folder enter that folder and then execute that command.