BGE water/underwater shader (WIP)

This is a water shader I am working on in my spare time. The work is based on my own observations of water characteristics and written from a scratch. It is still a work in progress. Right now the water surface is a plane, but support for real geometry waves is on its way. Due my really old computer I am currently on, I am almost unable to capture a video with decent framerate, but the shader uses simple calculations and runs very well on even 6 years old mid-end hardware. blend: