Descent 1 is a classic first-person shooter released in 1995 by Interplay and Parallax. Descent 2 released for the PC in 1996. It, along with its predecessor, was one of the first games with true 3-dimensional graphics, 6 degrees of freedom in movement, light sourcing, and the capability to join multiplayer games on-the-fly. D1X-Rebirth and DXX-Rebirth are modifications of the original Descent 1 and 2 sources that was released by Parallax (and are based on the D1X and D2X sources). It offering OpenGL graphics, advanced multiplayer, new features, and cross-platform compatibility. Now code bases of D1X-Rebirth and DXX-Rebirth merged and released as DXX-Rebirth.