ShaderBattle

Medium NatureAnimated

Twinkling starfield

A night sky of twinkling stars.

Play this challenge All challenges
The target picture for the shader challenge "Twinkling starfield"
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 534 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

Grid
uv * float2(40.0, 30.0)
Star in cell
only where hash(cell) > 0.8
Star position
jittered by float2(hash(cell + 7.0), hash(cell + 13.0)) - 0.5, times 0.6
Star shape
1.0 - smoothstep(0.0, 0.25, distance from jittered center)
Twinkle
0.5 + 0.5 * sin(time * 3.0 + hash(cell) * 40.0)
Sky
lerp(float3(0.02,0.02,0.08), float3(0.1,0.05,0.2), uv.y)

Helper functions provided

The toolbox has: hash(). 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

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