Easy Filters

Posterize

Crush the image to 4 brightness levels per channel.

The target picture for the shader challenge "Posterize"
Recreate this picture. You pass at a 99% match, then try to write it in fewer characters than the par.

How this challenge works

You write a fragment shader that draws the picture above, live in your browser. A match bar shows how close you are, and the score combines accuracy, code size (the par is 714 characters in Unity (Built-in)) and GPU speed. Work in HLSL, GLSL, WGSL, Metal or Godot and export the result when you are done.

The numbers you need

Levels
4.0
Formula
floor(color * levels) / (levels - 1.0), clamped to 1.0 (use min)

Helper functions provided

The toolbox has: scene(). Add them above your frag function with one click.

Solve it in your language

Unity (Built-in), Unity (URP), Unreal, Shadertoy / WebGL, OpenGL (LWJGL, raylib), three.js, GameMaker, LÖVE (Lua), Godot, Apple (iOS, macOS), WebGPU / Bevy.

Start coding