frames/skills/frames-animation/adapters/three.md

name, description

name	description
frames-three	Three.js and WebGL adapter patterns for Frames. Use when creating deterministic Three.js scenes, WebGL canvas layers, AnimationMixer timelines, camera motion, shader-driven visuals, or canvas renders that respond to Frames hf-seek events.

Three.js for Frames

Frames supports Three.js through its three runtime adapter. The adapter does not own your scene. It publishes Frames time and dispatches a seek event so your composition can render the exact frame.

Contract

• Create the scene, camera, renderer, materials, and assets synchronously when possible.
• Render from Frames time, not wall-clock time.
• Listen for the hf-seek event and render exactly that time.
• Load models, textures, and HDRIs before render-critical seeking. Do not fetch them at seek time.
• Avoid requestAnimationFrame or renderer.setAnimationLoop as the source of truth for render-critical motion.
• Always set data-duration="<seconds>" on the root [data-composition-id] element. Unlike CSS/WAAPI/Lottie, the three adapter has no duration auto-inference — it only forwards time via hf-seek/__hfThreeTime, it doesn't inspect your scene for an AnimationClip/AnimationMixer length. Without data-duration (and no GSAP timeline), the render engine has no way to know how long to capture and fails with "Composition has zero duration". npx @hanzo/frames lint errors on this (root_composition_missing_duration_source).

The adapter sets window.__hfThreeTime and dispatches new CustomEvent("hf-seek", { detail: { time } }) on each seek.

Basic Pattern

<canvas id="three-layer"></canvas>
<script type="module">
  import * as THREE from "https://cdn.jsdelivr.net/npm/[email protected]/+esm";

  const canvas = document.getElementById("three-layer");
  const renderer = new THREE.WebGLRenderer({ canvas, alpha: true, antialias: true });
  // Match these to your composition's frame size.
  renderer.setSize(1920, 1080, false);
  renderer.setPixelRatio(1);

  const scene = new THREE.Scene();
  const camera = new THREE.PerspectiveCamera(35, 1920 / 1080, 0.1, 100);
  camera.position.set(0, 0, 6);

  const mesh = new THREE.Mesh(
    new THREE.IcosahedronGeometry(1.4, 4),
    new THREE.MeshStandardMaterial({ color: 0x64d2ff, roughness: 0.38 }),
  );
  scene.add(mesh);
  scene.add(new THREE.HemisphereLight(0xffffff, 0x223344, 2));

  function renderAt(time) {
    mesh.rotation.y = time * 0.7;
    mesh.rotation.x = Math.sin(time * 0.6) * 0.16;
    renderer.render(scene, camera);
  }

  window.addEventListener("hf-seek", (event) => {
    renderAt(event.detail.time);
  });

  renderAt(window.__hfThreeTime || 0);
</script>

#three-layer {
  width: 100%;
  height: 100%;
  display: block;
}

Loading Addons (GLTFLoader, OrbitControls, etc.)

For anything under three/addons/, use an importmap so bare specifiers resolve. The Frames lint recognizes both this form and the inline +esm import above — pick whichever your composition needs.

<script type="importmap">
  {
    "imports": {
      "three": "https://cdn.jsdelivr.net/npm/[email protected]/build/three.module.js",
      "three/addons/": "https://cdn.jsdelivr.net/npm/[email protected]/examples/jsm/"
    }
  }
</script>
<script type="module">
  import * as THREE from "three";
  import { GLTFLoader } from "three/addons/loaders/GLTFLoader.js";
  import { OrbitControls } from "three/addons/controls/OrbitControls.js";
  // ...
</script>

Pin the three version in both entries to the same value. Mixing versions across the map and bare imports causes silent breakage.

AnimationMixer Pattern

For GLTF or authored clip animation, seek the mixer directly:

function renderAt(time) {
  mixer.setTime(time);
  renderer.render(scene, camera);
}

If several mixers exist, seek all of them from the same time.

Good Uses

• Deterministic 3D objects, product spins, particles with seeded data, and shader plates.
• Camera moves derived from time.
• GLTF animation clips when assets are local and loaded before validation completes.

Avoid

• Using Date.now(), performance.now(), or clock deltas to update scene state.
• Leaving render-critical work inside a free-running animation loop.
• Loading remote models or textures at render time.
• Device-pixel-ratio dependent output. Pin renderer size and pixel ratio for video renders.
• Post-processing passes that depend on previous frame history unless you can reconstruct state from time.

Validation

After editing a Three.js composition:

npx @hanzo/frames lint
npx @hanzo/frames check

Credits And References

• Frames adapter source: packages/core/src/runtime/adapters/three.ts.
• Why data-duration is required here specifically (no auto-inference for this adapter): packages/core/src/runtime/init.ts (resolveAdapterDurationFloorSeconds) and the CSS/WAAPI/Lottie adapters' getInferredDurationSeconds, which the three adapter deliberately does not implement.
• Three.js WebGLRenderer docs: https://threejs.org/docs/pages/WebGLRenderer.html
• Three.js AnimationMixer.setTime() docs: https://threejs.org/docs/pages/AnimationMixer.html