This project contains some example shaders I have written by hand using the HLSL language.
video: https://youtu.be/_5dJDG7j3Uc
This shader was written in HLSL for Unity. It uses a packed texture map, with just the red and green channes filled, so it could be expanded with even more features without increasing the memory cost. It has a few different parameters, including colors, distortion strength, and panning speed. I did not invent the Fresnel Calculation used in this shader.