OpenTTD

OpenTTD is a simulation game for transportation and a clone of the proprietary game Transport Tycoon Deluxe ("TTD"). The game's source code is licensed under the terms of the GNU General Public License version 2.0.

At this time (February 2022), proprietary data files from the original TTD are not required to play the binary packed game. The game project has free/libre media files. There are official libre data sets for the graphics (OpenGFX), sounds (OpenSFX) and music (OpenMSX). Some GNU/Linux distributions already have packages for these, but if not, these can be downloaded and installed in-game from the extensions menu.

OpenTTD has many improvements over its inspiration, TTD, such as larger maps and online multiplayer play.

It was written in the C++ programming language using the SDL or Allegro library.

Development
Branches of OpenTTD releases are divided up into nightly, testing, and stable releases.

History
OpenTTD originated with Ludvig "Ludde" Strigeus when he started reverse engineering TTD in 2003. Eventually, the project bears fruit in 2004.

In October 2008 a graphics replacement set was released that uses the same license as the original game engine recreation project. That lead to the inclusion into Linux distributions like Fedora.

Version 1.0.0 was released in April 2010.

The official sound set of OpenTTD, OpenSFX, was meant to be a libre sound set for the game actually was under a non-libre license for a very long time, way past the OpenTTD 1.0.0 release. The sounds were licensed under Creative Commons Sampling Plus 1.0, a retired non-free licence (it has a non-commercial clause). So efforts have been made to completely rework the sound set to be 100% libre. Version 1.0.0 of OpenSFX, the first actually libre version, was released in March 12, 2021 without any big announcement. The sounds in OpenSFX are licensed CC BY-SA 3.0 from that point on.

Release history
See OpenTTD release history.