I’m having trouble using flow maps, maybe because I don’t use them as “flow” maps, but just for distorting textures. I have a material in which I use the normal map to distort other textures with the red and green channels, like you would with a flow map, and it works perfectly. However, I also want the normal map itself to be distorted almost like a fisheye lens. I want the normal map to look like it’s bulging outward and flowing (like a fisheye lens) and flow around the edge towards the left and right.
I’ve found an example of a fisheye lens, and it does work, though I want to know how I could make something like this, either in Photoshop or 3D to make the normal map flow like I want it to: