Slope blur from Substance Designer

Slope Blur Documentation

Code
Performs an advanced, High Quality blur where the Anisotropy/Direction is driven by a Grayscale "Slope Map". Picture it as the Slope Blur effect following the slopes of your Slope Map as if it were a Heightmap, similar to Directional Warp (which it is based on internally).

"Following the slopes" = angular derivative, which is already present in several library filters (ex. my peanut butter filter, This Way).

The "blur" component is not usable, but we can approximate a blur by iterating over tiny increments (for example, Wind Blur, or like I did here).

We already have a filter where blur intensity is controlled by an input map, but not blur direction as far as I know.

Thanks guys for lots of suggestions , I am still looking through them. But whatever Substance designer tells on its help page, for me it looks not like a regular blur but rather shifting/displacing an image in a few consecutive steps, samples as they call them. Here how it looks with only 4 samples

[img]https://www.dropbox.com/s/rwr3uxti3n4oltt/slopeblur.jpg?dl=0[/img]

Its subgraph only shows multiple "warp" and "blend". No blur at all. It's just with lots of steps it starts looking like a blur.

Actually I have no idea what the math behind the true Gaussian blur is but believe it's calculating expensive operation. Perhaps it's what the blur is , shifting pixels? But I just hoped to recreate it in FF using refraction. It's an analog of SD "warp", right?.

Thanks Indigo Ray. The only thing left is Min (darker) and Max(lighter) blending modes . I seems can't figure out how to modify it properly to make loop iterations using those other blending modes instead of "add". Whatever I try returns just black image. Not sure why.

in Substance Designer the Min(darker) allows to do true looking erosion and also nice drip/smearing/ halo effects.