Main sections
X_SETTEXTUREOFFSET
X_SETTEXTUREOFFSET dx#, dy#
Shifts the texture for all following polygons by dx#, dy#. Once an object has been drawn with a DRAW/X_DRAW command its texture is set and changes to X_SETTEXTUREOFFSET will have no affect on it.
With this tool you can simulate flowing water or moving clouds in the sky without changing the 3D objects, just shifting their textures each frame.