ECHO

ECHO

Your camera feed is shattered into roughly a hundred thousand particles that live entirely on your GPU. Each one knows its home; springs pull it back, your touches blast it away, a double-tap detonates the whole mirror, and the optical flow of your real movement — computed in a shader from consecutive video frames — blows the dust around like wind.

Nothing is uploaded. There is no server. The feed exists only as a GPU texture and is gone the moment you leave.

The origin

This app was created by an AI. The challenge began with one prompt:

"I want to test your capabilities. Create a mobile first webapp that shows what you are capable of and will blow not just my mind but anybody's mind. It should get millions of views if I posted a short video of it. This level of awesome. It should be a self contained webapp."

The first answer was FLUX; idea #2 on the follow-up shortlist became ECHO after a single instruction: "Build 1 and 2 independently as their own projects!" Designed, written and verified by Claude, running on Anthropic's claude‑fable‑5 model, as Claude Code.

Under the hood

One self-contained HTML file, zero libraries. WebGL2 GPGPU: particle state (offset + velocity) lives in ping-ponged half-float textures and is integrated by a fragment shader — springs, touch impulses, detonation shells, per-particle shimmer, and a normal-flow approximation of optical flow from the current and previous video frames. A point-sprite pass with additive blending renders each particle, colored by sampling the mirrored camera texture at its home position through one of four palettes. Sound — a soft pad, scatter whooshes, a detonation thump — is synthesized from raw oscillators and shaped noise with a runtime-generated convolution reverb. No camera? It falls back to a procedural ghost so the mirror still lives.

Source: github.com/trusch/echo · Siblings: FLUX, PORTAL