which colour function is this?

so basally, i am trying to displace the 1st texture by the amount of the second texture
but in the lists or colour functions, all i found are different ways of mixing the 2 textures

this is what i actually want to do (and failed)

there used to be a function in materials/textures called ‘warp’ I think, which distorted the channel on top of it based on grayscale values. I do not know if it still exists. There was also a function called tex mesh where you could warp a texture by moving the vertexes of a proxy object. I am also not sure if this still exists.