Id Tech 4

The Id Tech 4 is the successor engine of Id Tech 3 and was popularly known as Doom 3 Engine. The Engine was designed by the co-founder of the Id Software, John Carmack, Who have be Working on previous engine for the Doom and Quake. which are also widely recognized as marking significant advances in the field.
==History==
id Tech 4 began as an enhancement to id Tech 3. During development, it was initially just a complete rewrite of the engine's renderer, while still retaining other subsystems, such as file access, and memory management. The decision to switch from C to the C++ programming language necessitated a restructuring and rewrite of the rest of the engine; today, while id Tech 4 contains code from id Tech 3, much of it has been rewritten.
At the QuakeCon 2007, John Carmack, the lead graphics engine developer at id, said to LinuxGames: "I mean, I won't commit to a date, but the Doom 3 stuff will be open source". And like its predecessors, John Carmack has said that id Tech 4 will be released as open source.
At the QuakeCon 2009, Carmack said that he planned to petition ZeniMax Media to release the id Tech 4 source upon the release of Rage. As part of his keynote for QuakeCon 2011 he confirmed that the source code to Doom 3 will be out by the end of the year, after the release of Rage.
On November 16, 2011, Carmack announced on Twitter that he's writing new code for Doom 3's open source release, because "lawyers are still skittish about the patent issue around 'Carmack's reverse'". This refers to an implementation of stencil buffered shadow volume algorithms.
On November 22, 2011, Carmack released the Doom 3 source code on Github. The source does not include any of the 'Carmack's Reverse' code. According to Carmack, minor tweaks were made to the code to avoid any infringement.
==Hardware==
The original requirement of id Tech 4 was that it needed a high-end graphics processing unit (GPU) with fully programmable vertex and pixel shaders, such as the Nvidia GeForce 3 or ATI Radeon 8500, with at least 64 MB of VRAM. By E3 2002, the recommended GPU was "100% DirectX 9.0b compatible", such as the Radeon 9700 with 128 MB of VRAM. While the Radeon 9700's DirectX 9.0 features are not necessary to render the game, its advanced architecture, 256-bit memory bus, and efficiency were needed to run Doom 3 at high detail and playable speed. The "Ultra" graphics mode included in Doom 3 would not even run on the current popular graphics cards available in 2004, requiring at least 512 MB of video memory to display properly and at playable speeds, meaning that it was basically unusable at the time of release.
id Tech 4 resulted in the obsolescence of DirectX 7 graphics chips such as the widespread GeForce 2 and Radeon 7200, as well as older chipsets such as RIVA TNT2 and Rage 128, and software rendering (with an integrated Intel GMA). Until the advent of id Tech 4, a powerful CPU was able to somewhat compensate for an older video card. While John Carmack initially warned gamers not to purchase the GeForce 4 MX (which casual consumers often confused with the DirectX 8 capable GeForce 4 Ti, though it was at best an improved GeForce 2), its somewhat widespread adoption compelled id Software to add it to the list of supported cards. There have been cases of enthusiasts forcing Doom 3 to run on unsupported graphics chips, such as the long obsolete Voodoo 2, but these are unable to render the per-pixel lighting and bump mapping.
==List of Games that have used this Engine by proprietary license==
*Doom 3 - Id Software (2004)
*Doom 3: Resurrection of Evil (2005) – Nerve Software
*Quake 4 (2005) – Raven Software
*Prey (2006) – Human Head Studios
*Enemy Territory: Quake Wars (2007) – Splash Damage
*Wolfenstein (2009) – Raven Software
*Brink (2011) – Splash Damage
*Prey 2 (cancelled) – Human Head Studios
*Quadrilateral Cowboy (2013) - Blendo Games
Category:Wolfenstein (2009)
Category:Wolfenstein (2009) engine