{{Software Infobox
|image=FileValve0009.jpg|250px|The "Valve Guy" in a demonstration level created by Valve Corporation|Valve showcasing the GoldSrc engine. It was intended to be the introductory logo of the company in ''Half-Life'' but it was replaced with a simple video in the final version.
|developer=Wikipediaid Software|id Software (WikipediaQuake engine|original engine), modified by Valve Corporation
|programming language=
|operating system=WikipediaMicrosoft Windows|Microsoft Windows, WikipediaDreamcast|Dreamcast, WikipediaPlaystation 2|Playstation 2, WikipediaMac OS X|Mac OS X, WikipediaLinux|Linux
|status=Officially inactive, but still managed by third party developers
|license=Wikipediaproprietary software|Proprietary

'''GoldSrc''', or '''GoldSource''', is the retronym used internally by Valve Corporation|Valve Software to refer to the heavily modified ''Quake'' engine that powers ''Half-Life''. 

FileColoured lightmaps.jpg|thumb|right|GoldSrc colored lightmaps demonstration.
GoldSrc is a heavily modified version of the QuakeWorld engine codebase, which in turn is a development of the Quake engine's codebase.http// Quake Engine Hierarchy Some minor fixes from the ''Quake II'' engine were incorporated as it was developed.http// VERC Collective -''Half-Life'''s Code Basis

Originally, GoldSrc's netcode, the coding that handles online multiplayer, was similar to the one in the QuakeWorld engine. However, in 2001, Valve implanted a new netcode that was designed to make it easier for players with high ping to play well via "lag compensation".http// ''Half-Life'' / ''TFC'' / ''Counter-Strike'' Tweak Guide on

During the Half-Life 2 Beta|early development of ''Half-Life 2'', an experimental engine known now as Source was made, debuting with ''Counter-Strike Source'' and ''Half-Life 2'' in 2004.

While officially abandoned in favor of the Source engine (except for minor maintenance updates), the GoldSrc engine is still used by third party developers.

===Similarities with the Quake Engine===
* GoldSrc's map format, ".BSP", is very similar to ''Quake'''s map format, ".BSP" as well. The only major differences are with how it handles lighting storage and how the game loads textures.http// ''Half-Life'' .BSP Format on The .BSP versions of GoldSrc and ''Quake'' are so similar that early versions of Hammer could edit ''Quake'' and ''Quake II'' maps. With a few alterations, versions of Hammer not officially supporting ''Quake'' can be used to create ''Quake'' maps.http// QuakeAdapter for Worldcraft 3.3
* Uncompiled GoldSrc maps use the .MAP format, which is also used by ''Quake'''s uncompiled maps.http// Quake Specs v3.4 - Section 1 MAP Information
* Both the GoldSrc and ''Quake'' engine use the .WAD format to store and load textures. The only differences between the two formats is that each texture in a GoldSrc .WAD file has its own palette, instead of sharing from one palette used by all of the textures, an ability to load multiple .WAD files in ''Half-Life''; ''Quake'' uses only gfx.wad, and the file header; ''Quake'' uses WAD2, while GoldSrc uses WAD3.http// Gimp-developer ''Quake'' / ''Half-Life'' texture wad support The WAD2 (and thus, WAD3) format itself is based on the wcdoomWAD format used in the wcdoomDoom engine|''Doom'' engine.http// Quake Specs v3.4 - The format of WAD2 files In addition, the ''Half-Life'' SDK includes a tool for making .WAD files called Qlumpy. Qlumpy is also used to create ''Quake'' .WAD files.http// Quake Misc. Utilities - "qlumpy"
* The GoldSrc and ''Quake'' engines use .pak files to store data, such as levels and models.

=== Open Source Reimplementation ===
Unlike the source code of the Quake series from ID software, Valve never released GoldSrc as free software. Therefore fans did wikipediaGame engine recreation|Game engine recreation attempts on their own. They try to stay binary compatible to play as many mods as possible, extend limits and add modern features such as improved lightning as well as water reflection effects. It also comes with built-in support for wikipediaNvidia PhysX|Nvidia PhysX.http//

*While the engine has no official name, in the months before the release of ''Half-Life'', many computing magazines described the engine as being based upon "Quake Unified Technology".

*Erik Johnson explains the origin of the GoldSrc name in this quote from the http// Valve Developer Community

''"When we were getting very close to releasing ''Half-Life'' (less than a week or so), we found there were already some projects that we needed to start working on, but we couldn't risk checking in code to the shipping version of the game. At that point we forked off the code in VSS to be both $/Goldsrc and /$Src. Over the next few years, we used these terms internally as "Goldsource" and "Source". At least initially, the Goldsrc branch of code referred to the codebase that was currently released, and Src referred to the next set of more risky technology that we were working on. When it came down to show ''Half-Life 2'' for the first time at E3, it was part of our internal communication to refer to the "Source engine|Source" engine vs. the "Goldsource" engine, and the name stuck."''

==Licensed games==
* ''Half-Life'' (Valve, 1998)
* ''Half-Life Opposing Force'' (Gearbox, 1999)
* ''wccounterstrikeCounter-Strike|Counter-Strike'' (Valve, 2000)
* ''http// Team Fortress Classic'' (Valve, 1999)
* ''WikipediaGunman Chronicles|Gunman Chronicles'' (Rewolf, 2000)
* ''Half-Life Blue Shift'' (Gearbox, 2001)
* ''WikipediaJames Bond 007 Nightfire|James Bond 007 Nightfire'' (Gearbox, 2002)
* ''WikipediaRicochet (2000 video game)|Ricochet'' (Valve, 2000)
* ''Deathmatch Classic'' (Valve, 2002)
* ''wcdayofdefeatDay of Defeat|Day of Defeat'' (Valve, 2003)
* ''wccounterstrikeCounter-Strike Neo|Counter-Strike Neo'' (Valve, Namco, 2003)
* ''wccounterstrikeCounter-Strike Condition Zero|Counter-Strike Condition Zero'' (Valve, Ritual, Gearbox, Turtle Rock Studios, 2004)
* ''wccsoCounter-Strike Online|Counter-Strike Online'' (Valve, NEXON, 2008)

==See also==
*Zentraedi Tactical Battle Pod
==External links==
*{{YouTube|url=zrqx45nfyR4|text=Original Valve introduction logo for ''Half-Life''}} (complete video of the above image)
CategoryGame engines