The fire effect in the Doom intro recently got renewed attention due to Fabien Sanglard’s excellent book Game Engine Black Book: DOOM and blog post How Doom Fire was Done.

After looking through a couple of implementations, and realizing that the effect is achieved using very little code I decided create my own.

The original algorithm can be used to create a lot of things if you feed it with different variables and have a bit of imagination.

Play around with the sliders or try these configurations Umbrella, Rain, Fire, Mona Lisa, Fireball, Beam me up, Matrix

The mask is a 256x256 gif image where bright pixels marks the source(s) of the effect. The fire, has just a line in the bottom and the rain is just a line in the top.

The source code is on Github.