Wolfenstein 3D engine
Encyclopedia
The Wolfenstein 3D engine is the engine that powers Wolfenstein 3D
.
The biggest part of the engine is programmed by John Carmack. It is written in C
and x86 assembly language
. It features graphics (ray casting
), sound (WAV
and IMF
), player physics and game control.
, the game uses ray casting
. This technique emits one ray for each column of pixels, checks if it intersects a wall, and draws textures
on the screen accordingly, creating a one dimensional depth buffer
against which to clip the scaled sprites
that represent enemies, powerups, and props.
Before Wolfenstein 3D, the technology had already been used by id Software in 1991 to create Hovertank 3D
and Catacomb 3-D for Softdisk
. Other games using the Wolfenstein 3D game engine
or derivatives of it were also produced, including Blake Stone
, Corridor 7: Alien Invasion, Operation Body Count
, Super 3D Noah's Ark
, Rise of the Triad
, and Hellraiser, an unreleased Color Dreams
game planned for the PC and the Nintendo Entertainment System
.
According to id Software programmer John Carmack, the game's engine was inspired by a technology demo of Looking Glass Studios'
/Origin's
first-person
CRPG, Ultima Underworld: The Stygian Abyss
from 1991. Carmack claimed he could make a faster renderer. In this he was successful. The Wolfenstein engine lacks many features present in the Underworld engine, such as ceiling or floor height changes, sloped floors and lighting, but it ran well on relatively weak hardware.
The secret behind engine's performance is vertical scanline scaling algorithm. Unlike later engines and hardware rasterizers, the texture coordinate for the pixel is not calculated at runtime. Instead, a fixed set of several hundreds rendering functions is generated during game startup (or viewport size change) where all memory offsets are fixed. To keep the number of these procedures small, height is quantized, which can be easily seen when player is close to the wall, but not looking at it at a right angle.
Features include:
Limitations of the engine include:
"Holo-walls" are walls created by mapmakers using a glitch in the PC version's engine. They are walls that the player can walk through, and are used in some total conversions to simulate windows that players can climb through, and hedges that players can walk through. One way of creating holo-walls is to place a dead guard in a wall.
Rise of the Triad
uses a very heavily modified version of Wolfenstein 3D engine, which adds numerous new features.
Wolfenstein 3D
Wolfenstein 3D is a video game that is generally regarded by critics and gaming journalists as having both popularized the first-person shooter genre on the PC and created the basic archetype upon which all subsequent games of the same genre would be built. It was created by id Software and...
.
The biggest part of the engine is programmed by John Carmack. It is written in C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
and x86 assembly language
X86 assembly language
x86 assembly language is a family of backward-compatible assembly languages, which provide some level of compatibility all the way back to the Intel 8008. x86 assembly languages are used to produce object code for the x86 class of processors, which includes Intel's Core series and AMD's Phenom and...
. It features graphics (ray casting
Ray casting
Ray casting is the use of ray-surface intersection tests to solve a variety of problems in computer graphics. It enables spatial selections of objects in ascene by providing users a virtual beam as a visual cue extending...
), sound (WAV
WAV
Waveform Audio File Format , is a Microsoft and IBM audio file format standard for storing an audio bitstream on PCs...
and IMF
IMF (music)
IMF is an audio file format created by id Software for the AdLib sound card for use in their video games. The default filename extension is also "imf". The abbreviation stands for "id music file" or "id's music format"....
), player physics and game control.
Features and limitations
To render the walls in pseudo-3D2.5D
2.5D , 3/4 perspective and pseudo-3D are terms used to describe either:* 2D graphical projections and techniques which cause a series of images or scenes to fake or appear to be three-dimensional when in fact they are not, or* gameplay in an otherwise three-dimensional video game that is...
, the game uses ray casting
Ray casting
Ray casting is the use of ray-surface intersection tests to solve a variety of problems in computer graphics. It enables spatial selections of objects in ascene by providing users a virtual beam as a visual cue extending...
. This technique emits one ray for each column of pixels, checks if it intersects a wall, and draws textures
Texture mapping
Texture mapping is a method for adding detail, surface texture , or color to a computer-generated graphic or 3D model. Its application to 3D graphics was pioneered by Dr Edwin Catmull in his Ph.D. thesis of 1974.-Texture mapping:...
on the screen accordingly, creating a one dimensional depth buffer
Z-buffering
In computer graphics, z-buffering is the management of image depth coordinates in three-dimensional graphics, usually done in hardware, sometimes in software. It is one solution to the visibility problem, which is the problem of deciding which elements of a rendered scene are visible, and which...
against which to clip the scaled sprites
Sprite (computer graphics)
In computer graphics, a sprite is a two-dimensional image or animation that is integrated into a larger scene...
that represent enemies, powerups, and props.
Before Wolfenstein 3D, the technology had already been used by id Software in 1991 to create Hovertank 3D
Hovertank 3D
Hovertank 3D is a vehicular combat game developed by id Software and published by Softdisk in April, 1991. It is considered a significant precursor of the first-person shooter genre, made popular by id Software's subsequent releases, Wolfenstein 3D and DOOM...
and Catacomb 3-D for Softdisk
Softdisk
Softdisk is a software and Internet company based in Shreveport, Louisiana. Founded in 1981, its original products were disk magazines...
. Other games using the Wolfenstein 3D game engine
Game engine
A game engine is a system designed for the creation and development of video games. There are many game engines that are designed to work on video game consoles and personal computers...
or derivatives of it were also produced, including Blake Stone
Blake Stone: Aliens of Gold
Blake Stone: Aliens of Gold is a first-person shooter computer game created by JAM Productions and published by Apogee Software. It uses the Wolfenstein 3D game engine to render graphics in first person, while adding many features....
, Corridor 7: Alien Invasion, Operation Body Count
Operation Body Count
Operation Body Count is a 1994 first-person shooter that used the Wolfenstein 3D ray casting engine. It was developed and published by Capstone Software.- Plot :...
, Super 3D Noah's Ark
Super 3D Noah's Ark
Super Noah's Ark 3D is an unlicensed video game for the Super Nintendo Entertainment System and for DOS. It was released by the biblical video game producer Wisdom Tree in 1994, and was the only commercial SNES game that was not officially sanctioned by Nintendo...
, Rise of the Triad
Rise of the Triad
Rise of the Triad: Dark War is a first-person shooter video game that was first released on February 17, 1995 and developed by Apogee Software . The members of the development team involved referred to themselves as "The Developers of Incredible Power"...
, and Hellraiser, an unreleased Color Dreams
Color Dreams
Color Dreams was a company that developed video games for the 8-bit Nintendo Entertainment System . While most companies that developed NES games obtained an official license from Nintendo to produce game cartridges, Color Dreams was unusual in that it developed NES games without an official license...
game planned for the PC and the Nintendo Entertainment System
Nintendo Entertainment System
The Nintendo Entertainment System is an 8-bit video game console that was released by Nintendo in North America during 1985, in Europe during 1986 and Australia in 1987...
.
According to id Software programmer John Carmack, the game's engine was inspired by a technology demo of Looking Glass Studios'
Looking Glass Studios
Looking Glass Studios was a computer game development company during the 1990s.The company originally formed as Looking Glass Technologies, when Blue Sky Productions and Lerner Research merged....
/Origin's
Origin Systems
Origin Systems, Inc. was a computer game developer based in Austin, Texas that was active from 1983 to 2004...
first-person
First person (video games)
In video games, first person refers to a graphical perspective rendered from the viewpoint of the player character. In many cases, this may be the viewpoint from the cockpit of a vehicle. Many different genres have made use of first-person perspectives, ranging from adventure games to flight...
CRPG, Ultima Underworld: The Stygian Abyss
Ultima Underworld: The Stygian Abyss
Ultima Underworld: The Stygian Abyss is a first-person role-playing video game developed by Blue Sky Productions and published by Origin Systems...
from 1991. Carmack claimed he could make a faster renderer. In this he was successful. The Wolfenstein engine lacks many features present in the Underworld engine, such as ceiling or floor height changes, sloped floors and lighting, but it ran well on relatively weak hardware.
The secret behind engine's performance is vertical scanline scaling algorithm. Unlike later engines and hardware rasterizers, the texture coordinate for the pixel is not calculated at runtime. Instead, a fixed set of several hundreds rendering functions is generated during game startup (or viewport size change) where all memory offsets are fixed. To keep the number of these procedures small, height is quantized, which can be easily seen when player is close to the wall, but not looking at it at a right angle.
Features include:
- SpritesSprite (computer graphics)In computer graphics, a sprite is a two-dimensional image or animation that is integrated into a larger scene...
used for objects - TextureTexture mappingTexture mapping is a method for adding detail, surface texture , or color to a computer-generated graphic or 3D model. Its application to 3D graphics was pioneered by Dr Edwin Catmull in his Ph.D. thesis of 1974.-Texture mapping:...
d walls
Limitations of the engine include:
- Looking and/or moving up and down is not supported.
- It does not support differences in brightness of the lights.
- It does not support differences in geometrical height.
"Holo-walls" are walls created by mapmakers using a glitch in the PC version's engine. They are walls that the player can walk through, and are used in some total conversions to simulate windows that players can climb through, and hedges that players can walk through. One way of creating holo-walls is to place a dead guard in a wall.
Games Using the Wolfenstein 3D Engine
- Wolfenstein 3DWolfenstein 3DWolfenstein 3D is a video game that is generally regarded by critics and gaming journalists as having both popularized the first-person shooter genre on the PC and created the basic archetype upon which all subsequent games of the same genre would be built. It was created by id Software and...
- Spear of Destiny
- Blake Stone: Aliens of GoldBlake Stone: Aliens of GoldBlake Stone: Aliens of Gold is a first-person shooter computer game created by JAM Productions and published by Apogee Software. It uses the Wolfenstein 3D game engine to render graphics in first person, while adding many features....
- Blake Stone: Planet StrikeBlake Stone: Planet StrikeBlake Stone: Planet Strike is the sequel to the computer game Blake Stone: Aliens of Gold, made by JAM Productions and released on October 28, 1994, by Apogee Software...
- Operation Body CountOperation Body CountOperation Body Count is a 1994 first-person shooter that used the Wolfenstein 3D ray casting engine. It was developed and published by Capstone Software.- Plot :...
- Corridor 7Corridor 7Corridor 7: Alien Invasion is a first-person shooter computer game developed and published by Capstone Software. It was widely ignored for its outdated Wolfenstein 3D engine, which was technologically surpassed by Doom at the time...
- Super 3D Noah's ArkSuper 3D Noah's ArkSuper Noah's Ark 3D is an unlicensed video game for the Super Nintendo Entertainment System and for DOS. It was released by the biblical video game producer Wisdom Tree in 1994, and was the only commercial SNES game that was not officially sanctioned by Nintendo...
Rise of the Triad
Rise of the Triad
Rise of the Triad: Dark War is a first-person shooter video game that was first released on February 17, 1995 and developed by Apogee Software . The members of the development team involved referred to themselves as "The Developers of Incredible Power"...
uses a very heavily modified version of Wolfenstein 3D engine, which adds numerous new features.
Predecessors
A few 3D games used the technology developed by Carmack before Wolfenstein 3D.- Hovertank 3DHovertank 3DHovertank 3D is a vehicular combat game developed by id Software and published by Softdisk in April, 1991. It is considered a significant precursor of the first-person shooter genre, made popular by id Software's subsequent releases, Wolfenstein 3D and DOOM...
- Catacomb 3-D
- Catacomb Abyss
- Catacomb Armageddon
- Catacomb Apocalypse
External links
- [ftp://ftp.idsoftware.com/idstuff/source/wolfsrc.zip Source code] at id Software's FTP server
- Engine source code and compiling instructions
- DieHard Wolfers Forum - Forum about Wolf3D and programming