Flag In Wind Screensaver
The Flag In Wind screensaver simulates fabric properly: a grid of masses joined by springs, pinned along one edge and pushed by a wind that shifts in strength and direction. It runs in the browser with nothing to install; press ESC to exit.
How the Flag In Wind screensaver works
The saver renders with three.js on your GPU. The library is vendored into this site rather than fetched from a CDN, and is loaded only when a 3D screensaver actually runs.
It reads nothing external — the simulation runs in the browser and is rendered with three.js.
The scene resizes with the window and releases its WebGL context when the saver stops, so shuffle mode and Multi-view can cycle 3D savers without exhausting the browser's context limit.
If WebGL is unavailable the saver says so on screen rather than showing an empty black box.
A worked example
A 34×22 sheet of points is joined by three kinds of constraint: structural along the weave, shear across the diagonals, and bend between every second point. Each frame integrates the points forward, then relaxes those constraints four times so the cloth resists stretching. The folds are not drawn — they emerge because the fabric cannot get any longer, which is the whole difference between simulation and animation.
Settings & tips
- Accent and Background recolour the scene; Speed changes the pace of both the motion and the camera.
- Add it to a Multi-view grid, though 3D savers are heavier than the 2D ones and a few per screen is plenty.
- Press ESC at any time to leave fullscreen.
Frequently asked questions
- Why not just use a sine wave?
- Because a sine wave has no idea the fabric cannot stretch. It looks convincing from one angle and wrong from every other, and it can never produce the sharp creases that appear when a real flag snaps over.
- What are the three constraint types for?
- Structural springs hold the weave together, shear springs stop the sheet collapsing into a parallelogram, and bend springs give it stiffness so it drapes like fabric rather than a chain net.
- Does this need a special browser or plugin?
- No. It uses WebGL, which every current desktop and mobile browser supports. Nothing is installed and no plugin is required.
- Does it cost anything or need an account?
- No. Every screensaver here is free, runs in the browser and needs no sign-up.