August 10th, 2014



I have been tinkering with the vanilla source code of Wolfenstein 3D from 1992. Even though it
is more than 20 years old and has rotten for modern systems, you can still compile it if you recreate the environment.
All you need is :

  • Wolfenstein 3D source code.
  • DosBox.
  • The Compiler Borland C++ 3.1.
  • Wolfenstein 3D shareware (for the assets).



Setup filesystem

Open a command line and create two folders, one for each DOS drive needed:

  
   cd ~
   mkdir system
   cd system
   mkdir c
   mkdir a
   cd ~


 


Download

  • Download Borland 3.1 to system/a.

  • Download Wolfenstein 3D source code to system/c

  • Download VGA files to system/c (the purpose of those is explained at the bottom of this page.



    cd system/a
    curl -O http://fabiensanglard.net/Compile_Like_Its_1992/tools/BCPP31.zip
    

    cd ../c
    curl -O http://fabiensanglard.net/Compile_Like_Its_1992/tools/wolfsrc.zip
    curl -O http://fabiensanglard.net/Compile_Like_Its_1992/tools/vgafiles.zip


  

Now we have all the files in the filesytem. Just to check, type:


   cd ..
   find ~/system


  


You should have the following :



    /Users/fabiensanglard/system
    /Users/fabiensanglard/system/a
    /Users/fabiensanglard/system/a/BCPP31.zip
    /Users/fabiensanglard/system/c
    /Users/fabiensanglard/system/c/vgafiles.zip
    /Users/fabiensanglard/system/c/wolfsrc.zip


  


Decompress everything


    cd ~/system/a
    unzip BCPP31.zip

    cd ~/system/c
    unzip vgafiles.zip
    unzip wolfsrc.zip



DosBox

Download and start DosBox:




Mount

Mount the filesystem, one folder for each drive :



   Z:/> mount c ~/system/c 
   Z:/> mount a ~/system/a

  


Install the compiler

Now is time to install Borland C++ 3.1 :


    Z:> a:
    A:> cd BCPP31
    A:> install

 





Press enter when you select the source drive ( it should already be A drive )



Install Wolfenstein 3D source code

We have a system running and a compiler on it: Time to decompress (again) the source code.


  A:> c:
  C:> cd
  C:> install






Type ‘C’




Keep the default path: WOLFSRC




Y to create the directory.

Installing !

Compiling

Start Borland C++ 3.1:


     
     C:> cd
     C:> cd borlandc
     C:> cd bin
     C:> bc.exe

  




After pressing OK, use the mouse or the shortcuts to Project -> Open Project ....WOLFSRCWOLF3D.PRJ:


Select Options -> Directories and change the value as follow :


    Include Directories: C:BORLANDCINCLUDE

    Library Directories: C:BORLANDCLIB

    Ouptput Directories: OBJ

    Source Directories:  C:WOLFSRC

    



Let’s try to compile: Compile -> Build All



We get an error: “Cannot find executable TASM”


Exit Borland C++, we need to set the PATH:


     
     C:> CD ..
     C:> PATH=C:BORLANDCBIN
     C:> BC.EXE

  


Getting the assets

Download the shareware version or even better: Purchase as full version on Wolfenstein 3D.


    cd ~/system/c
    curl -O http://fabiensanglard.net/Compile_Like_Its_1992/tools/1wolf14.zip
    unzip 1wolf14.zip

Go back to DosBox and install the game to C:WOLF3D.


  C:> c:
  C:> cd 
  C:> cd 1wolf14
  C:1WOLF14> install

  

After installation of the game, copy the .EXE we just compiled to the game folder,



    C:> c:
    C:> cd wolf3d
    C:WOLF3D> copy WOLF3D.EXE WOLF3D.OLD
    C:WOLF3D> copy ../WOLRSRC/WOLF.EXE .

  


Running the game

Try to run it:



    C:> cd wolf3d
    C:WOLF3D> copy WOLF3D.EXE WOLF3D.OLD
    C:WOLF3D> copy ../WOLRSRC/OBJ/WOLF3D.EXE .
    C:WOLF3D> WOLF3D.EXE


  



Hm, that looks weird…..






Uh…



What ?



I did not remember it like that….



Ok something must be very wrong here !!


What happened ?

It has to do with the production access pipeline and how they are used by the engine.
When Adrian Carmack and Kevin Cloud were done crafting all the graphic files, they used a tool (IGRABed) to pack them together.
The output was made of 3+2 files.

  • VGAHEAD.WL1
  • VGAGRAPH.WL1
  • VGADICT.WL1

The VGAHEAD file is an index containing pointers to the VGAGRAPH where the data is stored huffman compressed. VGADICT
contains the huffman dictionaries to decompress the data.

The two other files produced:

  • GRE.H
  • GRE.EQU

Are compiled into engine as seen in the following drawing :



What are the .H and .EQU files needed for? In short, to allow access by name. When IGRABed assembled all files
it would also create an enum with matching indices:

GRE.H


            enum{ 
            H_WOLFLOGOPIC
            GETPSYCHEDPIC
            L_GUYPIC
            .
            .
            } graphicnums

    

GRE.EQU


            
            H_WOLFLOGOPIC  = 0
            GETPSYCHEDPIC  = 1
            L_GUYPIC       = 2

    

This way when the engine requested a particular asset, it could use a logical name (L_GUYPIC) instead of a “magic number” (2).

That means the engine shipped with the indices of the images in the VGA files HARD-CODED. Since the assets and
codebase evolved after shipping wolf3D shareware (with Spears of Destiny), the newly compiled game indices do not
match the location in the original assets files.


Running the game (again)

Fortunately there is a simple solution to this problem: Somebody regenerated the VGA assets so they match the indices in the .H and .EQU
released with the source code. Just copy those files (if you use the shareware assets you will have to change the file extension from .WL6 to .WL1).


  C:> copy C:vgafilesVGADICT.WL6 C:WOLF3DVGADICT.WL1
  C:> copy C:vgafilesVGAGRAPH.WL6 C:WOLF3DVGAGRAPH.WL1
  C:> copy C:vgafilesVGAHEAD.WL6 C:WOLF3DVGAHEAD.WL1

Let’s try again:



  C:WOLF3D> WOLF3D.EXE
  

It works !!

Yet we are are not done !

VGA framebuffer and screen aspect ratio

It may not be obvious to people that never saw the original game but the DosBox image above is not what people saw in 1992.
The VGA framebuffer was 320×200 but the CRT monitors had an aspect ratio of 4:3. Which mean the framebuffer was stretched vertically
when sent to the monitor. DosBox has an option to compensate for that :



     vi ~/Library/Preferences/DOSBox 0.74 Preferences
  
    [render]
    # frameskip: How many frames DOSBox skips before drawing one.
    # aspect: Do aspect correction, if your output method doesn't support scaling this can slow things down!.
    # scaler: Scaler used to enlarge/enhance low resolution modes.
      # If 'forced' is appended, then the scaler will be used even if the result might not be desired.
      # Possible values: none, normal2x, normal3x, advmame2x, advmame3x, advinterp2x, advinterp3x, ...

    frameskip=0
    aspect=false
    scaler=normal2x


Change that aspect to true:



Try again :



  C:WOLF3D> WOLF3D.EXE
  


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