The two studies before this one were generated outright — noise grew the specimen, profiles and ratios cut the movement. That approach breaks here: no amount of noise will draw you Europe. So this one takes two small pieces of public data, and makes everything they touch.
A globe with weather, sunlight, and cities visible on the night side — and it had to carry the homepage, not just a case page. That second half set the constraints: it has to hold up at a glance, it has to survive being dragged, and it cannot cost a visitor half a megabyte of imagery before the first sentence of the page has rendered.
Natural Earth coastlines at 1:50m, simplified to a tenth of a degree, and every settlement over 200,000 people: 200 kB of vectors. Ocean depth, biome colour, cloud deck, city glow and the terminator are all computed from them at load.
Lighting is one direction in world space, so the terminator sweeps across the surface as the globe rotates. Day breaks over a coastline instead of sitting still — the thing that makes a globe feel like a planet rather than a textured ball.
The halo fades on how close each line of sight passes to the planet, not on the silhouette of the sphere drawing it. That one change is the difference between an atmosphere and a visible bubble around the globe.
Coastlines are filled to a canvas as a land mask — rings that straddle the antimeridian are cut there, or a continent smears across the map. A second pass measures distance from land out to sea and stores it as a shelf channel, which is what turns coasts turquoise and leaves the abyssal plains almost black.
The cloud deck is baked on the GPU in a single pass: fractal noise sampled on the sphere each pixel maps to, so it wraps at the antimeridian and does not pinch at the poles, then banded by latitude — wet at the equator, dry at the horse latitudes, stormy in the mid-latitudes. The same field is read twice by the surface shader, once where you are standing and once offset along the sun, so the deck throws a shadow on the ground beneath it.
City lights are drawn as splats scaled by the log of population, with satellite towns scattered around each one. Scale mattered more than brightness: at a first attempt each metro was a thousand kilometres wide and North America fused into a single white mass.
pagehide — a visitor who lands and scrolls straight past never pays for the
renderer.prefers-reduced-motion
stops the rotation, the pulses and the grain.A globe that reads as Earth from across a room and holds up when you drag it: weather that moves at its own rate, cities that come on as the terminator passes, a limb that glows because of how air thins rather than because a sphere was drawn slightly larger. It runs the same code on the case page and on the homepage, with different framing and one less layer of post.