Doom Style Fire

This is a graphical effect inspired by the early PS1 style DOOM game, and here I recreated it for the Godot 3.X engine.

One of the minor tricks in this, was using a viewport texture as a buffer to retain the previous frame's state and passing that in for the next frame.

=> Implemented as part of a large DOOM Fire collection
=> Fabien Sanglard's Blog post on implementation