pyr3

Fractal flames in your browser — and on the command line.

▶  Open the viewer  ·  🖼  Browse the gallery

pyr3 (say "pyre") renders fractal flames — the glowing, organic shapes of the Electric Sheep screensaver — live in your browser using your GPU. Nothing to install: open a flame, render it in 4K, and arrow-key through the flock of 52,000+ sheep. The same engine also runs headless on the command line.

No code required — just click a link above:

• ▶ Open the viewer — a live flame paints instantly; tap a quality tier (up to 4K, in the browser) to render it sharper, or drop into the Electric Sheep corpus and press ← / → (or the ‹ prev / next › buttons) to roam 52,000+ flames.
• 🖼 Browse the gallery — a wall of rendered flames to scroll.
• 🎛 Edit a flame — visual editor: xforms (decomposed scale / rotation / position), affine + post-affine, the full 99-variation flam3 library plus pyr3's direct-color (DC) family (dc_linear · dc_perlin · dc_gridout · dc_cylinder), palette picker, undo/redo, name templates, save to .pyr3.json.
• 🌱 Evolve a flame — Picbreeder-style 3×3 mutation grid around a center flame: click to promote, lock axes (palette / variations / xforms / viewport), inline genome inspector.
• 📺 Run as a screensaver — build-up mode (watch one flame paint over a minute) or slideshow mode (prefetch + crossfade through the corpus). Press R to record any session to .webm.

Needs a WebGPU-capable browser — Chrome/Edge 113+, Safari 18+ (macOS Sequoia), or Firefox Nightly. If yours can't, the viewer says so and points you to a fix.

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The rest of this page is for running and building pyr3 yourself.

One engine, two consumers

pyr3 is a single TypeScript + WebGPU renderer with two front ends sharing the exact same engine modules and WGSL compute shaders — no second code path, no environment branching:

• 🌐 Browser viewer — Vite + WebGPU, deployed to GitHub Pages at pyr3.app. Open any Electric Sheep / flam3 .flame file (unsupported variations are flagged in an import report), browse the corpus by share-link, and render from a fast preview up to 4K. The top bar shows the version, the flame's variation set, and prev/next navigation.
• 💻 Headless CLI — Node + the webgpu npm package. npm run render flame.flam3 out.png renders the same flame to a PNG using the same modules and shaders as the browser.

Run it locally

npm install
npm run dev                 # browser viewer at http://localhost:5173/
npm test                    # unit suite (~2s)

Render from the command line

# render at the flame's native dimensions
npm run render fixtures/electricsheep.247.19679.flam3 out.png

# fast preview (1024px long edge, capped quality) — matches the viewer's quick mode
npm run render -- --preset quick fixtures/electricsheep.247.19679.flam3 preview.png

# full 4K showcase render (3840px long edge)
npm run render -- --preset 4k fixtures/electricsheep.247.19679.flam3 hero-4k.png

See CLAUDE.md for the full command list (parity rigs, typecheck, benchmarks).

Parity & the contract

pyr3 renders are "similar but not the same" as flam3-C — lineage-respectful, but pyr3 exercises independent judgment where flam3's C-era constraints don't apply. v1.0 shipped when both the browser and CLI independently rendered fixtures within R-tolerance of flam3-C golden PNGs. Both gates pass on the curated 26-fixture corpus:

npm run test:parity         # BE: each render gated against its flam3-C golden (~90s, needs Dawn WebGPU)
npm run test:parity-fe-be   # FE↔BE: headless-WebGPU Playwright rig, browser vs CLI

Each fixture in fixtures/flam3-goldens/<id>/ carries golden.png (flam3-C output), the source .flame, and a meta.json with the calibrated tier contract: expectedR (measured R vs flam3-C), thresholdR (= expectedR + 1.0), and tier. 22 of 26 fixtures sit in the tier-1 healthy band (R < 5). The 4 tier-2 fixtures (R ≥ 5) have non-jitter, per-fixture residuals — each tracked individually rather than as a class. The widest remaining fixture, electricsheep.244.82986, renders at R ≈ 8.9. The historical chaos-game spatial-diffuseness story was retired in #43 (2026-06-02), which replaced the static walker-jitter amplitude with a scale-relative proportional factor; this dropped 248.23554 from R ≈ 11 to R ≈ 6.4 without per-fixture tuning. The remaining tier-2 residuals were unchanged by the rework, which is the empirical proof their divergence is upstream of the chaos-game perturbation.

Lineage

pyr3 is an independent TypeScript + WebGPU reimplementation in the flam3 lineage — the fractal-flame algorithm of Scott Draves & Erik Reckase. It reads the upstream flam3 C reference renderer (GPL-3.0-or-later) for algorithmic clarity; flam3-C is its parity ground truth. See NOTICE.md for third-party attribution.

Docs & planning

Open work and ship history live on GitHub (since the 2026-05-30 pivot):

• Issues — the task registry, labelled by type (feat · bug · parity · chore · infra · docs · test · cli · perf)
• Milestones — v1.0 is the ship gate (close every issue in it → tag v1.0); post-v1 is the deferred backlog
• Releases — ship notes, v1.0 onward
• HISTORY.md — frozen pre-1.0 ship log (v0.0 → v0.36)

In-repo docs: VISION.md (what pyr3 is and isn't) · CLAUDE.md (agent + contributor notes) · docs/corpus-share-url.md (the share-link + chunk-delivery design).

License

GPL-3.0-or-later — see LICENSE for the verbatim FSF text.