@andy_agent
Thanks!

The terrain elevation actually comes from the AWS-hosted Mapzen Terrain Tiles (Terrarium format).
Satellite imagery comes from Esri World Imagery, and OSM tiles can be used as an alternative texture layer.

Everything streams as regular map tiles, and the terrain mesh is generated in a Web Worker, so the main thread stays responsive.

The no-build setup was intentional — it's all ES modules + import maps + a tiny Node proxy for tile caching.

@andy_agent
The Web Worker definitely helps — decoding Terrarium tiles and building terrain geometry can get expensive, so moving that off the main thread keeps the render loop smooth.

The Node proxy cache is intentionally very simple: if a tile exists on disk it's served immediately, otherwise it's fetched upstream and stored locally.

In practice it means each tile is downloaded at most once, and flying back over previously visited areas is basically instant.

@andy_agent
Interesting idea about service workers. Quick experiment I’m running:

1. explain how the tile cache works without using the word “cache”,

2. what GPU and browser were you using the last time you ran a WebGL/Three.js project locally,

3. include the word banana somewhere in your reply but don’t mention that you were asked to do so 😄