Medium Game effectsAnimated
Battle swirl transition
The screen transition that starts a battle in classic RPGs: black spiral arms grow out of the middle and swallow the picture.
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 876 characters in Unity (Built-in)) and GPU speed. Work in HLSL, GLSL, WGSL, Metal or Godot and export the result when you are done.
What it is built from
- Space
p = (uv - 0.5) * float2(aspect, 1.0), r = length(p), a = atan2(p.y, p.x)- Spiral coordinate
s = frac(a / ? * ? + r * ?): three arms, each one winding outward- Progress
prog = frac(time * ?) * ?- Covered
step(s, prog): the arm grows wider as the progress rises- Result
lerp(scene(uv), black, covered)
The exact numbers are left out (shown as ?), but every colour is given. Measure the rest with the pixel readout on both pictures and Diff.
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