GoldSrc

Development

The basis of GoldSrc is the engine used in the video game Quake, albeit with heavy modification by Valve Corporation, at the time called Valve Software. While the engine served as the basis for GoldSrc, Gabe Newell has stated that a majority of the code used in the engine was created by Valve themselves, not taken from Quake. GoldSrc's artificial intelligence systems, for example, were essentially made from scratch. The engine also reuses code from other games in the Quake series, including QuakeWorld, and Quake II, but this reuse is minimal in comparison to that of the original Quake. In 1997, Valve hired Ben Morris and acquired Worldcraft, a tool for creating custom Quake maps. The tool was later renamed to Valve Hammer Editor and became the official mapping tool for GoldSrc.

Prior to the creation of the Source engine, the GoldSrc engine had no real title and was simply called "The Half-Life engine". Once Source was created, Valve forked the code from the Half-Life engine to make the Source engine. This created two main engine branches, each used for different purposes. One was titled "GoldSrc", and the other "Src". Internally, any games using the first variant were referred to as "Goldsource" in order to differentiate the two branches. Eventually, it became something of a moniker for the engine and was adopted as the official title externally.

Valve Corporation released versions of the GoldSrc engine for OS X and Linux in 2013, eventually porting all of their first-party titles utilizing the engine to the platforms by the end of the year.

Half-Life series

Half-Life was the debut title of both GoldSrc and Valve Corporation. It went on to receive critical acclaim, winning over fifty PC Game of the Year awards. The game was followed up with two expansions, Half-Life: Opposing Force and Half-Life: Blue Shift, both of which ran GoldSrc and were developed by Gearbox Software. Half-Life: Decay, an expansion pack for Half-Life only released on PlayStation 2, was released in 2001 alongside Half-Life's debut on the platform. Unlike other games in the series, it never received an official version for Windows, however an unofficial version of the game was released by independent developers in 2008. Half-Life: Decay was the final iteration in the Half-Life series to run on GoldSrc, with Half-Life 2 and all titles succeeding it running on the Source engine.

Other Valve Corporation titles

Valve developed a number of titles using the GoldSrc engine, many of which were based on original user-made modifications of Half-Life. Team Fortress Classic, released officially by Valve Corporation in 1999, was one of such games (based on an older Quake mod, Team Fortress). Counter-Strike, Ricochet, and Day of Defeat were also originally modifications, the rights to which were purchased by Valve. Counter-Strike evolved into its own series with the release of Counter-Strike: Condition Zero in 2004, and while Counter-Strike: Source ran on the Source engine, further games in the series still used GoldSrc. Counter-Strike Neo, Counter-Strike Online, and Counter-Strike Nexon: Zombies, released in 2005, 2008, and 2014 respectively, utilized GoldSrc as their basis, despite the development of the Source engine having been completed and the first version released.

Third-party titles and modifications

The GoldSrc engine was also used for a variety of third-party titles and modifications not directly developed by Valve Corporation. Rewolf Software used the engine for the game Gunman Chronicles in 2000, and James Bond 007: Nightfire was developed by Gearbox Software using a modified version of GoldSrc in 2002.

Unofficial, community-made modifications of GoldSrc were also produced. Notable titles include Natural Selection, Cry of Fear and Sven Co-op , with Valve's Team Fortress Classic, Counter-Strike, and Day of Defeat all being based on GoldSrc mods of the same names. Sven Co-op is now a standalone game for free on Steam (software).