Satellites, end to end: CelesTrak element sets behind the same TTL cache
the weather and the flights use, served as TLEs rather than as positions,
and propagated in the browser with SGP4.
Sending elements is the same trick `flights/plan.ts` plays and it has a
better excuse here — a TLE *is* the closed form, valid for days either
side of its epoch, so one cacheable fetch every six hours replaces a poll
and every viewer agrees about where everything is.
Two things are worth knowing about the shape of it:
- There is no region parameter. An aeroplane at 10,000 m is local and
a satellite at 550 km is above the horizon for a circle two thousand
kilometres across, so one catalogue serves both boards and the client
decides what is above its own horizon. Only the observer is per-city,
which is why `main.ts` shares the elements and rebuilds the catalogue.
- The layer draws on a dome, because it cannot draw anywhere else.
`world.metres(550_000)` is 21,000 scene units against a far plane at
3,000. Azimuth and elevation are real; the radius carries nothing.
Off by default: a clone that started pulling CelesTrak on `npm run dev`
would have volunteered somebody else's bandwidth for its onboarding.
Godmode gets the two dials that point at the sky rather than at the
light — fabricated traffic, which composes with a live ADS-B feed instead
of replacing it, and a switch for the satellite layer with a count beside
it. Both are god-only lies about the inputs, in the manner of the weather
override.
`satellite.js` is the second runtime dependency this package has taken.
Its entry point star-exports an Emscripten build that cannot be shaken
out, so `noWasmPropagator` in the Vite config cuts it: 308 kB of WASM
loader for a bulk propagator nothing calls, against 26 kB for the SGP4
that does the work.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Tera
The map view of Lumbridge Simulate — cities from above, in three.js. Its other half, Spaces, is the offices you walk into: one engine and one asset library, seen from outside and from inside.
Apache 2.0. Runs at tera.lumbridgecorp.com.
What it is
An engine plus data packs. The engine renders terrain, coastline, a built city on real street grids, bridges, roads, markers and air traffic. A city pack is pure data — coastlines, hills, districts, landmarks, camera chapters — so adding a city is a data contribution anyone can review, not a fork.
San Francisco ships today. Los Angeles / Orange County / Riverside is next; New York after that.
A plan view sits top right: the board drawn flat, with the footprint of the camera's own frustum on it, so you can see where you are looking from outside the shot. Click or drag it to move the camera; scroll it to dolly. It is a 2D canvas rather than a second WebGL context, drawn from the same city pack, and it follows the sun into the night along with everything else.
Who sees what
Three tiers, resolved once at boot by src/access.ts:
| anonymous | signed in | admin | |
|---|---|---|---|
| the map, the plan view, the named chapters | ✅ | ✅ | ✅ |
| observed weather and live aircraft | ✅ | ✅ | ✅ |
| the office | public depth — shell, furniture, viewpoints, nobody home | full depth, with presence | full depth |
| the marker feed | per TERA_MARKERS_ACCESS |
✅ | ✅ |
the godmode panel (G) — date, season, weather override, counters, pose editor |
— | — | ✅ |
The sky is public on purpose. Cloud cover over San Francisco is a government sensor reading, and the aircraft are broadcasting their positions unencrypted to anyone with a receiver; neither is something an account can grant you access to. Gating them cost the only moment that makes this project land — real fog rolling off the Pacific onto a city you recognise, at the real time of day, on a first visit.
The markers are the one feed that can carry something private, so the server
decides. TERA_MARKERS_ACCESS is members by default and an operator has to
say public out loud, which /api/v1/health then announces in degraded[].
The default is the safe answer rather than the common one, because the failure
mode is silent: nothing errors, nothing looks broken, the data is just readable
by the internet.
These are drawing decisions, not a security boundary, and src/access.ts
says so at length. Live data and office presence are withheld by the API, from
a caller it does not recognise; the client tier stops the app asking for
something it will not get. Admin is granted only by TERA_ADMIN_SUBJECTS on the
server — never inferred in the browser, and never from an API that failed to
answer. A deployment with no API at all is open, because "clone it and it works"
is the promise; it is not "clone it and you are an administrator".
Quick start
npm install
npm run dev
Using the engine
import { createScene } from "@lumbridge/tera/engine/scene.ts";
import { createStage } from "@lumbridge/tera/engine/stage.ts";
import SAN_FRANCISCO from "@lumbridge/tera/cities/sf.ts";
// One stage per canvas, for the life of the page. Cities are put on it and
// taken off again; a renderer per city leaks its shadow map on every switch.
const stage = createStage(canvas);
const scene = await createScene(stage, {
city: SAN_FRANCISCO,
markerPalette: { hiring: 0x4ade80, closed: 0xef4444 },
});
scene?.setMarkers([
{ id: "1", lat: 37.7765, lng: -122.4241, label: "Somewhere", colorKey: "hiring" },
]);
createScene is async because the heightfield is built in a Worker — half a
million samples, about 730 ms on the Bay Area, and not on the main thread. It
resolves to null if the build was abandoned through options.signal, which is
what makes switching city mid-build cheap.
The engine renders Marker[] and looks colours up by colorKey in a palette
you supply. It does not know what your markers mean — that mapping lives in
your adapter. This is what lets one renderer serve a private map coloured by
one scheme and a public map coloured by another, without either being a fork.
Adding a city
Write src/cities/<id>.ts exporting a City. Trace the coastline and parks by
hand, place hills as radial peaks, and give each district its street bearing.
Two rules, and they are not stylistic:
- Do not import geometry from OpenStreetMap. OSM and Nominatim output is ODbL — share-alike, and incompatible with this repo's licence.
- Do not commit logos or brand assets. They are trademarks, not code.
See ARCHITECTURE.md §3 for the full reasoning, and NOTICE for the attribution and data-provenance statement.
Aircraft
The engine takes a FlightSource. Two ship here: SimulatedFlights (original,
flies real approach and departure corridors) and AdsbFlights (open community
ADS-B feeds such as adsb.lol).
FlightRadar24 is deliberately absent — their terms forbid scraping and forbid redistributing their data, so a client for it cannot live in an Apache-2.0 repository. Commercial sources belong in private deployments. The best long-term answer is an RTL-SDR receiver: first-party data with nothing to comply with.
Layout
src/engine/ renderer — terrain, blocks, structures, markers, flights, scene, minimap
src/cities/ data packs — pure geography, no code
src/adapters/ where outside data plugs in
src/tools/ instruments — god-only, dynamically imported, never statically
engine never imports cities; neither imports adapters.
Nothing under src/tools/ may be reached by a static import from the app. It is
loaded by one await import() behind access.can.debug, so a visitor who is
not an admin does not download the code at all — which is the strongest
available reading of "nothing here runs for a non-god visitor": not a hidden
panel, not a disabled panel, no panel. src/tools/index.ts states the rule and
what silently undoes it.
