DarkPlaces engine

Main Features

Fully integrated per pixel lighting and shadowing technology (diffuse, normalmapping, specular lighting, with shadowmaps or shadow volumes supported), lightmapping and deluxemapping (directional shading for lightmaps, supporting full normalmap and specular features), and a variety of material effects fully integrated in one shader system that deals with all situations.
Variety of file formats supported (Quake1 and Quake3 file formats, skeletal models, various image formats, ogg vorbis support on all sound effects, and more).
Game logic scripting in QuakeC programming language.
Advanced networking designed to scale from dialup to broadband, with automatic distance-based prioritization for optimal close-range gameplay in a densely populated world.
Realistic global fog feature with height limit for seamless blending with sky.
ODE physics engine integration.
Per-polygon collision detection optimized for large static meshes, as well as Quake brush technology.
Background music support with sequential and random playlists and playlist switching (with resume), in ogg vorbis or wav format.
CD audio support.

Model formats

Quake MDL, Quake2 MD2, Quake3 MD3, DarkPlaces DPM (converters from SMD and MD5), DarkPlaces/Cube2 IQM (Blender exporter available, SMD converter available), UnrealEngine PSK, Wavefront OBJ, Quake1 BSP, Quake3 BSP.