# Paper Birds, Real Shadows — `paper-birds@1.0.0`

Three folded paper cranes rest in afternoon light. Their shadows escape, become a living flock and return to the paper. Ray-traced origami. Loops.

Three origami cranes, orange, red and white, sit on warm paper in a slanting shaft of afternoon sun. Their softly projected shadows slip free, split into a flock of small birds that circles above the cranes, then fly back and settle into the shadows. The cranes are ray-traced triangular meshes with properly projected shadows, and the flock is animated bird by bird. The 12 seconds loop. The film has no settings.

- Kind: background; status: published; digest sha256:a3fa3665cb65dcc439f68b8848cfb056226cb76f8dbd6c587352d1cfbcef2b00
- Role: Shader film (three.js): Origami shadow theatre, a finished 12-second portrait film with no settings.
- Implementation: three; entry `src/paper-birds.js`
- Files: https://aipixelwizard.com/registry/paper-birds/1.0.0/<path> (`LICENSE`, `asset.json`, `demo.js`, `index.html`, `src/paper-birds.js`)
- Manifest JSON: https://aipixelwizard.com/api/v1/visuals/paper-birds/versions/1.0.0
- Runnable demo: https://aipixelwizard.com/registry/paper-birds/1.0.0/index.html (open over http; it imports sibling packages by relative path)
- Dependencies (exact): `three@0.185.1` (source) — Renderer and a full-screen shader material.; `apw-runtime@1.0.0` (demo) — Demo harness.

## Exports
- `createPaperBirds() => { scene, camera, setSize(width, height), update(time), dispose() }` — The film as one full-screen shader; render its scene with its camera straight to the canvas.

## Composition
- Inputs: The time in seconds, 0 to 12. The film has no other settings.
- Outputs: An opaque full-frame picture, already in display colours: render it straight to the canvas.
- Coordinates: Composed for a 4:5 portrait frame and measured by the frame height: in a wider frame the picture stays centred at full height and its background fills the sides; in a narrower one, such as 9:16, the sides are cropped.
- Lighting: A warm slanting shaft of afternoon sun across the paper, with soft projected shadows.
- Timing: The shadows slip free from about half a second in, form a flock through the first four seconds, circle until about nine seconds, then return to the cranes.
- Works with: —
- The cranes are ray-traced triangular meshes, not drawn shapes.
- It is one of the heavier films: about 45 ms a frame on an integrated GPU.
- Every pixel is a function of the time alone, so frames can be rendered in any order.

## Output and loop
- 1080×1350, 30 fps, 12 s, procedural
- Seamless loop: yes — Every part of the film is a function of the time modulo its length, and every motion completes whole cycles, so the last frame meets the first.
- Verified 2026-10-10 in Chrome 154.0.8037.97 headless on Linux 7.0.0-38-generic (x64), Node 22.14.0 (WebGL 2 via SwiftShader (software)); deterministic: yes; loop check: Frame 0 vs end state (progress 1): mean |Δ| 0.0000, max |Δ| 0 of 255.

## Use it
New project: Create a WebGLRenderer on a canvas (no antialiasing), call createPaperBirds() once and film.setSize(width, height); then for each frame call film.update(timeInSeconds) and renderer.render(film.scene, film.camera).

Existing project: Copy src/paper-birds.js, which needs only three. Render film.scene with film.camera into your own canvas or render target; the output is opaque and already in display colours, so use no tone mapping or colour conversion.

Reuse ideas:
- Wellness intro: the flock rises from about 1 s and circles until about 9 s.
- Seamless loop: the birds settle back into the shadows, so it repeats cleanly.
- Quiet backdrop: the empty paper at the top and bottom holds a title.

## Limitations
- The film is finished: it has no settings. To change colours or timing, edit the shader.
- It is composed for a 4:5 portrait frame.
- Its length is fixed at 12 seconds; repeat the loop to fill a longer clip.

## License
MIT. Copyright (c) 2026 AI Pixel Wizard. Released under the MIT License. See LICENSE in this folder.

Provenance: From the owner's collection Twenty Impossible Worlds: the original GLSL ES 3.00 shader of the film “Paper Birds, Real Shadows”, created with ChatGPT / Codex and used as published, wrapped for AI Pixel Wizard as a three.js full-screen shader in October 2026. The collection's synthesised soundtrack is not part of this ingredient.