I posted something yesterday night that didn't work at all (hardcoded paths). But the TD library and editor are soon finished. Here's a rather blocky example. Only mouse control this time: move and turn with arrow keys, look up and down with PgUp and PgDown.
Textures from opengameart.org.
I need to add support for water and change of lighting so that you can make parts of a map more gloomy. Also, you can't add models to your map yet (that's why things look blocky, only walls, floor, ceiling and heightmap are used).