Custom automatic colorization system

[agg23]

Implement a system for calculating colors a la SGB.

See:

https://www.youtube.com/watch?v=CASuRsN7bkk
https://github.com/IgnacioLeivaP/Virtual-boy-colorize/blob/main/Virtual%20boy%20Colorize/vb_colorize.glsl
https://github.com/AshleyPikachu/Super-Bit-Shader/blob/main/super_bit_glsl/VB/SBS%20VB%20-%20Cherry.glsl