cobejs

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

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)?