D2X-XL used to compute its lightmaps on the CPU, and every wall got a lightmap of the same size, no matter how large the wall was.

Lightmaps are now computed on the graphics card. Their detail follows the size of the walls, lamps cast shadows with soft edges, and light that is reflected by the walls is taken into account.

The lightmaps of a level are computed when the level is loaded for the first time and then kept in a cache. They are computed again when the level, its textures or its lights have changed.

Lightmap quality has three levels and is set in the render options while no game is running.