Simulated Thin Film Interference Node

This is a massive shader I put together that simulates accurate thin film interference. No other accurate ones exist (that I know of) right now.

Implementation in GLSL on shadertoy: https://www.shadertoy.com/view/dl2Szm
(code is in Common)

I implemented this technique:
https://www.gamedev.net/tutorials/_/technical/graphics-programming-and-theory/thin-film-interference-for-computer-graphics-r2962/