ThreeJS Equirect Env Reflection is a glossy image-based-lighting demo in which a slowly spinning torus knot draws its colour and reflections entirely from a single wrap-around photograph of its surroundings.
How it works. The scene is lit by an equirectangular environment map — one panoramic image, stretched 360° like a flattened world map, that stands in for the sky and everything around the object. Before it can be used for realistic shading, three.js runs it through a PMREM step that pre-blurs the panorama into a stack of progressively rougher versions, letting the material look mirror-sharp when smooth and softly diffuse when rough. This is the heart of image-based lighting (IBL): rather than placing individual lamps, the whole environment becomes the light source. The demo carries two such probes — a high-dynamic-range EXR lightprobe and an ordinary PNG — and ACES filmic tone mapping maps their brightness onto the display.
How you interact:
- Orbit and zoom — drag to circle the torus knot; pinch or scroll to move within a fixed near-to-far range.
- Swap environments — a control panel switches the map between the EXR and PNG probes.
- Shape the material — sliders set the surface roughness, metalness and exposure.
- Reveal the floor — a debug toggle drops in a ground plane that mirrors the same environment.
One of a set of three.js examples rendered live on the Switch's GPU inside the brewser browser, running entirely offline.