Introduction to id Tech 4 engine
Creation of models, animations, environment and all other content for computer games is quite specific issue. Compared for example with creation of models and animations for CG scenes for films, some procedures are similar, other completely different. And what is worse, each game engine has its own procedures for content creation. However, there are main “rules” that apply to content for all computer games. One of the most important “rules” is an effort to create optimal and effective representation of content while maintaining adequate hardware requirements and high audio-visual quality.
These tutorials deal with procedures of content creation and its transfer to id Tech 4 engine (rather Doom 3). Keep in mind that these tutorials require knowledge of Adobe Photoshop, Autodesk Maya etc. In other words, you have to have skills with bitmaps, 3D modeling and animation. For this reason, tutorials will not deal with teaching these areas. Contrary, main attention will be given to procedures directly related to transferring content to id Tech 4 engine, workflow in associated editors and other useful tools, which will ease our work.
In the beginning, id Tech 4 engine was referred to as Doom 3 engine. First alpha versions were based on previous Quake 3 engine (id Tech 3). During the development id switched from C language to C++ and so part of an older engine were rewritten too. Like previous Carmack’s 3D engines, this id Tech 4 engine was also build under OpenGL. So main advantages at that time were kick-ass visuals and also cross-platform support (Microsoft Windows, Linux, Mac OS X).
John Carmack began work on id Tech 4 after completing the Quake 3 Arena, so that means in the end of year 1999. But unexpected long development caused that the first game on this engine – Doom 3 – wasn’t released until summer of year 2004. This game was quite successful. But there was also a wave of criticism aimed particularly at the darkness of the game. Some people claimed that Doom 3 is just “pitch black darkness with sound“. Despite similar criticisms this game earned its place in the world of computer games and received many awards.
The main technological contribution of the engine is feature called “Unified lighting and shadowing”. Previous three-dimensional games, such as already mentioned Quake 3, used separated type of lighting for static elements (game environment aka map) and dynamic elements (characters, moving models etc.). Data for storing lights and shadows in the static map has been made in advance and saved into so-called “lightmaps”. On the contrary, dynamic lighting on the moving models etc. has been rendered on fly. This separation often led to unrealistic lighting of dynamic objects in otherwise static-lit map. Simply put, that is why the id Tech 4 has “unified” lighting. This also dropped off the need to pre-render map lighting, which saves a lot of time during map development.
Another important technology is called “Megatexture”. This technology allows us to use high resolution texture instead of small tiled textures on terrains. Doom 3 supports Megatexture technology in very limited way. When Doom 3 was released, this technology was still under development. First game, which used all capabilities of Megatexture was Enemy Territory: Quake Wars. This was the game where id Tech 4 engine proved its ability to render also huge beautiful outdoor scenes, which were missed by that time in this engine.
Id Software is currently developing new remarkable technologies that will be used in games based on id Tech 5 engine. According to recent reports on upcoming Rage and Doom 4 we can just look forward to.
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