1st of all, no you cannot do that.
There’s a basic understanding there:
A Tex Object is actually a “database” of pixels, if you want to do something like blur, you need more that one pixel, The “database” contains all pixel data that you need to do this. That’s why the SpiralBlur function need the full pack of pixels.
But a tex sampler is just a “function” which only return one pixel of data based on the UV input. (UVs are like “address” of data in the “database”.) So it wont give you data of the nearby pixels.
Therefore functions like SpiralBlur and NormalfromHeight demands a tex object for input, not a tex sampler. tex sampler is almost equals to a vector 4 constant.
If you need to modify the function, you can always copy the source code and modify it to whatever you need. Like a “Normal from RVT Heightmap”.