webgl-experience

# WebGL Experience Skill Produce a single self-contained `index.html` that renders a real-time WebGL (or WebGL2) visual full-screen, with a clean typographic overlay on top. ## Why this is a powered artifact OpenDesign detects `getContext('webgl2')` / `new Worker` / `SharedArrayBuffer` and renders this file in **powered preview** — a cross-origin-isolated iframe with `allow-same-origin`. That means real Web Workers, `SharedArrayBuffer`, WASM, and the full GPU pipeline are available. You do **not** need to work around the opaque sandbox. Prefer `webgl2` for modern features; fall back to `webgl` when the effect allows. ## Resource map ``` webgl-experience/ ├── SKILL.md ← you're reading this └── example.html ← a working WebGL2 aurora-field reference (READ FIRST) ``` ## Workflow ### Step 0 — Read the reference Read `example.html` end to end. Note the shape: one full-viewport `<canvas>`, a fragment-shader draw loop on a fullscreen triangle, a DPR-aware resize, and a `requestAnimationFrame` tick. The overlay (`kicker` → `h1` → `sub`) is pure HTML/CSS layered above the canvas via `z-index`. ### Step 1 — Choose the visual Pick ONE technique that fits the brief: - **Fragment-shader field** (default): domain-warped fbm noise, flow fields, plasma, gradients. Cheapest, always 60fps. - **Raymarched scene**: SDF spheres/boxes with soft shadows for a 3D hero. - **Instanced geometry**: thousands of points/quads driven by a vertex shader. - **Post-processed image**: sample a data-URI texture and distort/dither it. ### Step 2 — Build `index.html` - Keep it **one file, zero external requests** (inline the shader source; embed any texture as a `data:` URI). Powered mode allows CDN loads, but self-contained previews are faster and portable. - Always: `alpha:false`, DPR clamped to 2, `viewport` on resize, and a guard that shows a graceful message if the context is null. - Compile shaders with error logging (`getShaderInfoLog`) so a typo fails loudly, not silently black. ### Step 3 — Overlay + brand - Map the two `:root`-level accent colors to the active DESIGN.md when one is present; otherwise use a restrained dark palette with a single vivid accent (the reference uses lime `#63fe13`). - Headline ≤ 14ch, one supporting line. Never cover the whole canvas — the visual is the hero. ### Step 4 — Self-review (P0) - [ ] Renders continuously at ~60fps; the FPS badge updates. - [ ] No WebGL console errors; `getError()` clean after first frame. - [ ] Resizes crisply on window resize (no stretching / blur). - [ ] Readable overlay contrast over the brightest frame. - [ ] Degrades to a message (not a blank page) if `webgl2` is unavailable.