Quake II engine

A screenshot of Quake II
Developer(s)	id Software (John Carmack, John Cash, and Brian Hook)
Final release	3.21 / December 22, 2001; 22 years ago (2001-12-22)
Repository	github.com/id-Software/Quake-2
Written in	C, Assembly (for software rendering & optimization)
Platform	Windows, Mac OS 8, Linux, PowerPC Macintosh, Amiga, Nintendo 64, Dreamcast, Xbox, PlayStation 2
Predecessor	Quake engine
Successor	id Tech 3, GoldSrc
License	GNU GPL-2.0-or-later
Website	www.idsoftware.com/business/idtech2/

The Quake II engine is a game engine developed by id Software for use in their 1997 first-person shooter Quake II.^[1] It is the successor to the Quake engine. Since its release, the Quake II engine has been licensed for use in several other games.^[2]

One of the engine's most notable features was out-of-the-box support for hardware-accelerated graphics, specifically OpenGL, along with the traditional software renderer.^[2] Another interesting feature was the subdivision of some of the components into dynamic-link libraries. This allowed both software and OpenGL renderers, which were selected by loading and unloading separate libraries. Libraries were also used for the game logic, with consequences including:

• Since they were compiled for specific platforms, instead of an interpreter, they could run faster than Quake's solution, which was to run the game logic (QuakeC) in a limited interpreter.^[3]
• id could release the source code to allow modifications while keeping the remainder of the engine proprietary.^[4]

The level format, as with previous id Software engines, used binary space partitioning. The level environments were lit using lightmaps, a method in which light data for each surface is precalculated (this time, via a radiosity method) and stored as an image, which is then used to determine the lighting intensity each 3D model should receive, but not its direction.^[5][6]

id Software released the source code on December 22, 2001, under the terms of the GNU General Public License v2.0 or later.^[7]

Games using the Quake II engine

Games using a proprietary license

Games based on the GPL source release

Ports

• Jake2 is a Java port of the Quake II engine's GPL release. It has since been used by Sun as an example of Java Web Start capabilities for games distribution over the Internet.^[10] In 2006, it was used to experiment playing 3D games with eye tracking.^[11] The performance of Jake2 is on par with the original C version.^[12]
• Yamagi Quake II is a port of Quake II to modern systems which aims to preserve the original gameplay.^{[13][14][15][16]}
• vkQuake2 is the original Quake II engine with additional Vulkan renderer created by Krzysztof Kondrak, a programmer from Poland. It was originally released in December 2018 under the GPLv2.^[17][18]
• Qfusion is a modification of the GPL version of the engine. The engine was used in the 2012 game Warsow.^[8][9]