Game Engine Black Book: Wolfenstein 3D (v2.1)

320 Pages·2019·6.305 MB·English

by  Fabien Sanglard

GAME ENGINE
BLACK BOOK
WOLFENSTEIN 3D
FABIEN SANGLARD
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Copyright
In order to illustrate how the Wolfenstein 3D game engine works, a few screenshots, im-
ages,sprites,andtexturesbelongingtoandcopyrightedbyidSoftwarearereproducedin
thisbook. Thefollowingitemsareusedunderthe"fairuse"doctrine:
1. Allin-gamescreenshots,titlescreen,signonscreen,totalcarnagescreen.
2. Allin-gamemenuscreenshots(mainmenu,soundmenu).
3. All3Dsequencetextures(bluewall,wood,darkwood,gridwall).
4. All3Dsequencesprites(brownguard,deadguard,deaddog).
5. All3DsequenceimagesusedfortheHUD.
6. AllscreenshotsofSpearofDestiny,Catacomb3-D,andHovertankOne.
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Acknowledgments
ThankstoJohnCarmack,JohnRomero,RomainGuy,VictoriaHo,andAurelienSanglard
forgenerouslyhelping. Thisprojectwouldhavenevermaterializedwithoutthem.
Thanks to Jim Leonard and Foone Turing who volunteered their fleet of 286s, 386s, and
VGAcardstoaccuratelybenchmarkWolfenstein3D.
ThankstoJimLeonardforsharinghisencyclopedicknowledgeofPCsystemarchitecture
and programming. His patience in explaining sound systems and extended memory sys-
temshelpedthisbooktoshipwithaccurateinformation.
Thanks to Chet Haase, Daniel Thornburgh, Xiao Yu, and Chris Forbes for proofreading
andcatchingmistakes.
Thankstoreaderswhokindlyreportederrorsinthefirstedition:ChristopherVanDerWest-
huizen,pinterk,BryanStillwell,EliseyShemyakin,oneveu,IgorNikolaev,MikhailNaganov,
ghosttie, elieb, Amro, Thizz (@codyvasy), Olivier Cahagne, tronster, Cyril Mottier, Ted
Marynicz,EluanCostaMiranda,andJustinMeiners.
Thankstoreaderswhokindlyreportederrorsinthesecondedition: A.Piquet,Amro,Ben
Terris, Chris Chokan, David Snyder, Dennis Duda, Dmitry Minsky, Graeme McCutcheon,
JamesFMcMahon,JonathanJayet,LFaria,TimGarlick,andEliseyShemyakin.
–FabienSanglard
[email protected]
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How To Send Feedback
This book strives to be as accurate and as clear as possible. If you find factual errors,
spellingmistakes,ormerelyambiguities,pleasetakeafewminutestoreportthemonthe
GameEngineBlackBook: Wolfenstein3D companionwebpagelocatedat:
http://fabiensanglard.net/gebbwolf3d
Thanks:) !
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Foreword by John Carmack
Fabien’s commentary on the classic game engine codebases have been a wonderful re-
sourceontheweb,soIwasthrilledthathedecidedtostartexpandingthemallthewayto
booklength. WhileoftenovershadowedbyDoom,Wolfenstein3Ddoesholdasignificant
placeinvideogamehistory,anditremainsfuntorunaroundintoday,justlikedroppinga
quarterinaPacManmachine.
Despite being open source, the 16-bit code and assembly language is not easy to build
orexperimentwith, sofarfewerpeoplehavelookedintoitthanthelatercodebases. The
mostremarkablethingabouttheprojectfromtoday’sperspectiveisjusthowsmallitwas:
onelittledirectoryofcodefileswithnoexternaldependencies. BackthenIbarelytrusted
(with some reason!) the C standard library implementations that we had to work with, so
almosteverythingwasdoneinthosefewsourcefiles.
Iwas21yearsoldwhenIwrotemostofthecode,andIhadonlybeenprogramminginC
forayear,soitisfarfromamasterpieceofcodingstyle,buttherearestillsomethingsthat
weredonewell. Compiledscalersareacaseofcodespecializationtakentotheextreme,
which, combined with the low level VGA trick of multi-column writes and the progressive
performance characteristics of ray-casting make it much more even in framerate than a
conventional approach. The choice to use ray casting was also an important pragmatic
decision. I wasn’t experienced enough yet to do a solid implementation of a polygon, or
evenline-based,engine. Ray-castinggotmewhereIneededtobeatanacceptablecost.
So,setthewaybackmachinefor1992.
ACHTUNG!
–JohnCarmack
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