WebGL CRT Shader

by Matt Sephton — Sun, 04 Jan 2026 17:44:00 +0000

I’m releasing my WebGL CRT Shader as open source.

It creates a CRT/vintage TV effect so could be used in games, emulators, apps, demos, visuals, etc. It’s not a simulator just something that gives the same general old school vibe.

As a WebGL shader, it runs on the device’s hardware GPU in the browser and renders to a <canvas> (or offscreen canvas). I currently use it with Three.js, and the demo below uses just a 2D canvas.

It’s optimised to run well on low power devices as far back as iPhone XS, though I’m certain it can be optimised even further. PRs welcome! The easiest personal optimisation you might make would be removing processing of unused parameters.

Is it scientifically correct? Hell no. Does it look good? Yes. Does it give you the feels? Absolutely.

github.com/gingerbeardman/webgl-crt-shader/

History

It began as a shader for Love2D at the beginning of 2025 (here’s a gist of that one) and by the end of 2025 I had ported it to GLSL for a personal work-in-progress web game.

Live Demo

Reach for the sliders!

(You can scroll the demo horizontally on mobile)

![screenshot](https://cdn.gingerbeardman.com/images/posts/glsl-web-crt-shader.png)

^ Screenshot is Pico-8 classic Worm Nom Nom by Tic Tac Toad (kometbomb + iLKke) 🌸🍏🎩🐛💩

Phosphor Essence

by Matt Sephton — Wed, 07 Apr 2021 00:00:00 +0000

Photoshop 3.0 (1994) Monitor Setup, Phosphors reads like a wish list of the professional CRTs now adored by retro gamers:

- Barco
- Hitachi
- Ikegami
- Trinitron pic.twitter.com/VJLkRl7WgR
— Matt Sephton🎴 (@gingerbeardman) April 7, 2021

Get Info: #crt

WebGL CRT Shader

History

Live Demo

Phosphor Essence