[gavanwoolery]

Neat, dont have time to dive in the source right now but whats the trick? Light probes? Edit: Ah, nevermind its one click away:

"Illumination technique used here is:

Realtime direct shadowmapping with time blended lighmaps for global illumination on: walls, ceiling and floor.

For furniture we use spherical harmonics L2 with spatial and time blending for ambient light.

Reflections made with time blended box projected cubemaps for image based lighting on physically based materials.

Post processing done with color grading by LUT (lookup tables) and vignette."