Introduction

I received a mail the other day from Martins Upitis, who asked me really nicely if he could use my Cubic Lens Distortion Shader code into one of his GLSL shader. He was asking me if he could copy & tweak it a little bit. That was really funny to me since Martins is probably the guy who made me wants to learn shader in the first place after seeing one of his first shader he posted on blenderArtist, and also because he didn’t figure I was the same person asking him thousand of noobs questions on that same forum :p .
Of course I was so proud that I said yes, and he made it look so coooolll !!!

Source

Anyway I encourage you to go check out his post on BlenderArstists.org here : http://blenderartists.org/forum/showthread.php?t=175155&highlight=lens+distortion

His shader create vignetting, chromatic aberration, cubic distortion, depth of field, and a really smart animation texture based on 1bit alpha store in each RGBA channels (which gives a lot of frames – so smart)… it looks really great !

Blender File : http://www.pasteall.org/blend/1425 or mirror on this blog

controls:
buttons 1 and 2 enables post-process effects (vignetting, noise, edge-blur, and a new and awesome lens distortion filter, made by Francois Tarlier, and slightly modified by me).

Up/Down – shrink/grow the snowflake
mouse wheel up/down – chromatic dispersion amount

numpad:
7/4 – lens distortion coefficient
8/5 – cubic distortion amount
9/6 – image scaling amount