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cobejs

Use when adding a lightweight interactive globe with cobe (canvas setup, markers, interaction, performance, integration with React/Next.js).

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cobe.js — Lightweight WebGL Globe Skill

When to use

  • A “spinning globe” / location markers in hero or about pages
  • You want a small, focused globe lib (not full three.js)
  • Decorative + interactive (markers, rotation) with minimal setup

Key APIs/patterns

  • Core:
    • import createGlobe from "cobe"
    • const globe = createGlobe(canvas, { ...options, onRender(state) { ... } })
  • Important options (common):
    • devicePixelRatio, width, height
    • phi, theta (rotation angles)
    • scale, dark, diffuse
    • baseColor, markerColor, glowColor
    • markers: [{ location: [lat, lon], size, color? }]
  • Lifecycle:
    • globe.toggle() pauses RAF
    • globe.destroy() removes instance

Common pitfalls

  • Canvas sizing mismatch
    • Set CSS size AND set canvas width/height scaled for DPR.
  • Not updating on resize
    • Recompute width/height and recreate or update params.
  • Too high DPR on mobile
    • Clamp DPR to 1–2.

Quick recipe: responsive globe with markers

import createGlobe from "cobe";

const canvas = document.getElementById("cobe");
let phi = 0;

function setup() {
  const rect = canvas.getBoundingClientRect();
  const dpr = Math.min(window.devicePixelRatio, 2);
  canvas.width = Math.round(rect.width * dpr);
  canvas.height = Math.round(rect.height * dpr);

  const globe = createGlobe(canvas, {
    devicePixelRatio: dpr,
    width: canvas.width,
    height: canvas.height,
    phi: 0,
    theta: 0.2,
    dark: 0,
    diffuse: 1.2,
    scale: 1,
    mapSamples: 16000,
    mapBrightness: 6,
    baseColor: [0.2, 0.2, 0.25],
    glowColor: [1, 1, 1],
    markerColor: [0.8, 0.5, 1],
    markers: [{ location: [1.3521, 103.8198], size: 0.08 }],
    onRender: (state) => {
      state.phi = phi;
      phi += 0.01;
    },
  });

  return globe;
}

let globe = setup();
window.addEventListener("resize", () => {
  globe.destroy();
  globe = setup();
});

What to ask the user

  • Globe size and placement (hero, section, card)?
  • Marker locations + colors (brand-aligned)?
  • Interaction needs (drag to rotate vs. ambient spin)?
Repository
MengTo/Skills
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