Overview

The same stress test as the Earth-Scale Planet, but on createTorusTopology: a donut world whose surface area equals Earth's (major radius ~6,236 km, minor radius ~2,079 km, a 3:1 ratio). The identical elevation field, colour ramp, and altitude-aware cameras are reused — only the topology and the elevation-recovery math differ, which is the point of the topology + projection API.

The button in the top-left corner (hotkey V) switches to a pointer-lock fly camera (click the canvas to grab the mouse, WASD to move, Space/C for up/down, Q/E to roll, Shift to boost, Esc to release). Flying the inside of the hole is the interesting bit: the "up" direction comes from the sampled surface normal, so it stays correct even where the surface curves back over your head.

Points of interest at this scale:

• Anisotropic roots — the torus seeds a baseU × baseV grid of level-0 roots so tiles start approximately square, then the same quadtree LOD machinery refines both the outer equator and the inner hole seamlessly as you zoom.
• float32 precision floor — as with the planet, world positions are ~6e6 m, so maxLevel defaults to 14 (~10 m vertices). Raising it past ~15 quantises vertex positions to ~1 ULP apart and the close-up surface dissolves into shard noise.