Fathomlight: Live Wallpaper & Screensaver Maker

Fathomlight renders an endless field of glowing filaments with a raymarching fragment shader, then lets you save what you see. Drag to look around, scroll to change the field of view, shuffle through twelve named looks, and open Tune to set travel speed, filament density, tunnel width, and color by hand. Anything on screen can leave as a 4K PNG wallpaper, an MP4 or WebM clip, or an animated GIF. It runs on your graphics card, in the page, with no account and no upload.

Yes, completely free, with no hidden limits, no account, no watermarks, and no feature gates. Every resolution up to 8K is available to everybody, exports are unlimited, and nothing is held back for a paid tier. The images and clips you make are yours to use. If you want to support the work there are Donate and Support buttons at the top of the help panel, but nothing in the tool is locked behind them.

Open settings with the icon in the top corner and press Capture, or press S for an instant 4K PNG at the current settings. The capture panel opens on the Still tab with 4K already selected. Pick an aspect ratio that matches your screen, choose a size, and press Download. The panel pins the exact frame in the preview, so the file you get is the frame you framed, not wherever the animation drifted while you chose a size. The picture is rendered off screen at full resolution, so the view never resizes or flickers during a capture.

No. Everything runs locally in your browser with WebGL and JavaScript. There is no server, no upload, no sign in, and no image ever leaves your device. Files are written straight to your downloads folder by the browser. The only outside traffic is anonymous page analytics and the web fonts, plus one small GIF encoder script fetched from a public CDN the first time you export a GIF.

Raymarching is a way to draw a 3D image that has no 3D model in it. For every pixel a ray walks forward in steps, a math function reports how far the nearest surface sits, and light is added along the way. That function is the whole scene. This one folds space five times per step with a cosine, which turns a smooth tube into a thicket of thin bright strands, then colors each sample by its position and fades it with distance. Filament density controls how hard the fold bites, which is why small moves swing the look from soft smoke to dense coral.

A current browser with WebGL 2, which means Chrome, Edge, Firefox, or Safari 15.5 and later on desktop, iOS, iPadOS, or Android. No install, no extension, no plugin. The renderer is demanding, so the app measures its own frame time and lowers the render scale automatically on slower hardware. You can override that in Tune under Quality. Video recording needs MediaRecorder, which Firefox supports as WebM rather than MP4.

Yes. Drag one finger to look around, pinch with two fingers to change the field of view, and double-tap to randomize everything. The settings panel and the capture panel are both sized for thumbs. Mobile starts at a lower render scale to protect frame rate and battery, and the quality governor adjusts from there. One caution: 8K stills are blocked on iOS, because Safari caps total canvas area at about 16.8 million pixels, which 4K clears and 8K does not.

ShaderToy is a place to write shader code and share it, with an account, a code editor, and no real export. Fathomlight is the opposite trade: one shader, no code to write, named looks and plain-language sliders instead of uniforms, and a capture panel that hands you a 4K PNG, an MP4 clip, or a GIF in a couple of taps. Use ShaderToy to author a shader. Use this when you want a finished frame, a clip for a video, or a wallpaper, and you do not want to build one first.