If you want to control UV offset or tiling, you can do that before the VectorToRadial, and (if I remember correctly) you can grab DDY/DDX after your multiply/add, but before the VTRV function. I’m trying to find the original post, but it was along the lines of “any kind of math applied to the tex coord is fine to do DDY/DDX off of” so things like Add and Multiply are fine.
I think the Frac, Sqrt, and custom atan2 in the mat function break that though
