A brief foray into the Sketchfab API for the mixing of 2 textures.
Default method uses the 'Emit' channel.
This is faster, but emit map needs to be loaded and set at 0.01 in SketchFab
Second (original) method uses a hidden canvas to mix textures.
Lo fi texture used while sliding. (may require 'disable local-file restrictions')
Additional comments in source.
More yet to be done. Chip in on Github