Hard NatureAnimated
Campfire
A flickering flame that tapers upward and is narrow at the edges.
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 951 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
- x
(uv.x - 0.5) * aspect- Noise
fbm(float2(x * 3.0, uv.y * 3.0 - time * 1.5))- Heat
f = n * 1.6 - uv.y * 1.3 - abs(x) * 1.2 + 0.25- Ramp
black-red → red (1,0.2,0) → yellow (1,0.85,0.2) → white- Ramp edges
smoothstep(0.1,0.4) / (0.4,0.7) / (0.7,0.95) on f- Base
float3(0.05, 0.0, 0.0)
Helper functions provided
The toolbox has: hash(), vnoise(), fbm(). 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