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RBDOOM-3-BFG Readme -

Download it from the RBDOOM-3-BFG Mod DB Page


For discussions join the id Tech 4 Discord: , #rbdoom3bfg

Table of Contents

This file contains the following sections:

  1. About the Port
  2. ".plan"
  3. May or may not ".plan"
  4. Renderer Features Explained
  5. TrenchBroom Mapping Support
  6. General Notes
  7. License
  8. Getting the Source Code
  9. Compiling on Windows
  10. Compiling on Linux
  11. Compiling on macOS
  12. Installation, Getting the Game Data, Running the Game
  13. New Console Variables
  14. Known Issues
  15. Bug Reports
  16. FAQ

About the Port

RBDOOM-3-BFG is a modernization effort of DOOM-3-BFG.

RBDOOM-3-BFG is based on DOOM-3-BFG and the goal of this port is to bring DOOM-3-BFG up to latest technology in 2021 making it closer to Doom 2016 while still remaining a DOOM 3 port regarding the gameplay.

I started this project in 2012 and focused on making this code being future proof so other cool projects can build interesting things on top of it without the need to fix a lot of stuff first. Over 40 people all over the world contributed cool patches. Some results are:

Gaming / Graphics Related

  • Physically Based Rendering using GGX Cook-Torrence as in other modern engines (UE4, Unity) and 3D authoring tools like Blender 2.93 or Adobe Substance
  • Baked Global Illumination using Irradiance Volumes and Image Based Lighting that fix the pitch black areas
  • Soft shadows using PCF hardware shadow mapping. All 3 light types (point, spot, parallel/sun) are supported which means parallel lights (sun) use scene independent cascaded shadow mapping.
  • True internal 64 bit HDR lighting with filmic ACES tone mapping and gamma-correct rendering in linear RGB space
  • Enhanced Subpixel Morphological Antialiasing as a cheap alternative for MSAA and that works well with HDR. For more information see "Anti-Aliasing Methods in CryENGINE 3" and the docs at
  • Filmic post process effects like Chromatic Aberration and Dithering
  • Screen Space Ambient Occlusion used to only dim down the Global Illumination contribution like in the Frostbite engine
  • Bink video playback through libbinkdec (thanks to Daniel Gibson) or FFmpeg (thanks to Carl Kenner)
  • Cinematic sequences can be skipped (thanks to Biel Bestué de Luna)
  • Netcode fixes to allow multiplayer sessions to friends with +connect (manual port forwarding required)

Programming and Code Quality

  • Flexible build system using CMake allowing to add optional features like Vulkan rendering, FFmpeg for videos or OpenAL for sound
  • Linux support for both GCC and Clang with a proper SDL 2 OS layer including gamepad support
  • Win64 support and Visual Studio support up to VS 2019
  • macOS support (updated in 2021 thanks to Stephen Saunders)
  • OpenAL Soft sound backend primarily developed for Linux but works on Windows as well
  • Sourcecode cleanup using the Artistic Style C++ beautifier to ensure the Git diffs and logs are clean
  • Fixed tons of warnings using the Clang compiler
  • Fast compile times using precompiled header support which allows to compile the entire engine and builtin tools in less than 30 seconds on a Ryzen 9
  • Although not really supported but runs on exotic hardware like MIPS64, PPC64, ARM64 and E2K architectures
  • Updated idRenderLog to support RenderDoc and Nvidia's Nsight and only issue OpenGL or Vulkan debug commands if the debug extensions are detected. Reference:

Modding Support

RBDOOM-3-BFG allows mod editing and has many tiny fixes so custom content can be put into mod directories and the engine accepts it like vanilla Doom 3. DOOM 3 BFG wasn't designed for actual development or modding support. Many things like reading anything outside of the packed resource files was not supported. I also fixed many things in the renderer like r_showTris.

  • TrenchBroom Mapping Support - see more information in the TrenchBroom section
  • New PBR related material keywords like basecolormap, normalmap, rmaomap
  • invertGreen( normalmap.png ) material keyword to allow flipping the Y-Axis for tangent space normal maps
  • PNG image support
  • Collada .DAE model support in addition to .ase and .lwo for static map models
  • Wavefront OBJ model support to make it easier getting static models from Blender/Maya/3D Studio Max into TrenchBroom
  • Added back dmap and aas compilers (mapping tools, thanks to Pat Raynor) and improved them to work with TrenchBroom
  • Added in-engine Flash debugging tools and new console variables
  • Added Steel Storm 2 Engine render demo fixes
  • Merged LordHavoc's image compression progress bar which shows up in the map loading screen when loading and compressing new images from mods
  • Added support for Mikkelsen tangent space standard for new assets (thanks to Stephen Pridham)
  • Bumped the static vertex cache limit of 31 MB to roughly ~ 128 MB to help with some custom models and maps by the Doom 3 community
  • com_showFPS bigger than 1 uses ImGui to show more detailed renderer stats like the original console prints with r_speeds

If you want to start mod from a directory, you should first specify your mod directory adding the following command to the launcher:

"+set fs_game modDirectoryName"

so it would end up looking like: RBDoom3BFG +set fs_game modDirectoryName

IMPORTANT: RBDOOM-3-BFG does not support old Doom 3 modifications that include sourcecode modifications in binary form (.dll) You can fork RBDOOM-3-BFG and create a new renamed binary that includes all required C++ game code modifications.


If you want to see what is planned or in progress in a Trello/Kanban style manner look here: RBDOOM-3-BFG projects

Very certain short term goals are to port and extend some improvements from Justin Marshall's Iced-Hellfire-Dev branch:

  • Assimp -> MD5 converter pipeline to generate .md5mesh/.md5anim files from any FBX, DAE, glTF2 files
  • Improve MD5 files with a new Version 11 that allows to store normals for better control of smoothing groups
  • Native C++ weapons code
  • Native C++ AI & monsters code
  • Quake 3 gladiator multiplayer bot

Other short term goals:

  • DX12/Vulkan renderer backend using the NVIDIA Rendering Hardware Interface by Stephen Pridham which will lead the path to advanced Ray Tracing techniques
  • Optional RmlUI support as an alternative to Flash

May or may not ".plan"

Renderer Features Explained

Physically Based Rendering

Implementing Physically Based Rendering (PBR) in Doom 3 is a challenge and comes with a few compromises because the Doom 3 content was designed to work with the hardware constraints in 2004 and that even meant to run on a Geforce 3.

The light rigs aren't made for PBR but it is possible to achieve good PBR lighting even with the old content by tweaking the light formulars with a few good magic constants. However I also want to support the modding scene to allow them to create brand new PBR materials made with Substance Designer/Painter or other modern tools so multiple rendering paths have been implemented.

PBR allows artists to create textures that are based on real world measured color values and they look more or less the same in any renderer that follows the PBR guidelines and formulars.

RBDOOM-3-BFG only supports the standard PBR Roughness/Metallic workflow.

Adding PBR is a requirement to make the new content look the same in RBDOOM-3-BFG as in Blender 2.9x with Cycles or Eevee and Substance Designer. PBR became the standard material authoring since 2014. With RBDOOM-3-BFG modders can work with modern tools and expect that their content looks as expected.

The PBR implementation is restricted to standard PBR using the Roughness/Metallic workflow for now. Specialized rendering paths for skin, clothes and vegetation will be in future releases.

PBR Texture format

In Doom 3 a classic simple materials looks like this:

  qer_editorimage		textures/base_wall/snpanel2rust.tga
  bumpmap           textures/base_wall/snpanel2_local.tga
  diffusemap        textures/base_wall/snpanel2rust_d.tga
  specularmap       textures/base_wall/snpanel2rust_s.tga

It's usually rendered with Blinn-Phong specular with a fixed specular exponent. Specularmaps are more or less Gloss maps.

In RBDOOM-3-BFG it uses the PBR GGX Cook-Torrence formular and you can vary the roughness along the material like in other modern engines and you usually define a texture with the _rmao suffix.

RMAO Image Channels Description
Red Roughness
Green Metalness
Blue Ambient Occlusion

Example material:

  qer_editorimage   models/mapobjects/pbr/materialorb/substance/metal04_basecolor.png
  basecolormap      models/mapobjects/pbr/materialorb/substance/metal04_basecolor.png
  normalmap         models/mapobjects/pbr/materialorb/substance/metal04_normal.png
  rmaomap           models/mapobjects/pbr/materialorb/substance/metal04_rmao.png

The engine will also look for _rmao.[png/tga] overrides for old materials and if it finds those it will render them using a better PBR path. Old school specularmaps also go through a GGX pipeline but the roughness is estimated from the glossmap.

The Ambient Occlusion will be mixed with the Screen Space Ambient Occlusion and will only affect indirect lighting contributed by the environment probes.

Baked Global Illumination using Irradiance Volumes and Image Based Lighting

To achieve the typical PBR look from an artistic point of view it also means to that it is necessary to add indirect lighting. Doom 3 and even Doom 3 BFG had no indirect lighting.

Doom 3 BFG is a big game. Doom 3, Resurrection of Evil and Lost Missions sum up to 47 big single player levels with an average of ~60 - 110 BSP portal areas or let's call them rooms / floors. Each room can have up to 50 shadow casting lights and most of them are point lights. I needed a good automatic solution that fixes the pitch black areas without destroying the original look and feel of the game. I also needed to add environment probes for each room so PBR materials can actually reflect the environment.

So RBDOOM-3-BFG comes with 2 systems to achieve this and both are automatic approaches so everything can be achieved in a reasonable amount of time. The first system are environment probes which are placed into the center of the rooms. They can also be manually tweaked by adding env_probe entities in the maps. They use L4 spherical harmonics for diffuse reflections and GGX convolved mip maps for specular reflections. The second system refines this by using a light grid for each room which provides a sort of a localized/improved version of the surrounding light for each corner of the room.

Irradiance Volumes aka Light Grids

RBDOOM-3-BFG 1.3.0 brings back the Quake 3 light grid but this time the grid points feature spherical harmonics encoded as octahedrons and it can be evaluated per pixel. This means it can be used on any geometry and serves as an irradiance volume. Unlike Quake 3 this isn't radiosity which is limited to diffuse only reflections. The diffuse reflectivity is built using all kinds of incoming light: diffuse, specular and emissive (sky, light emitting GUIs, VFX).

Lightgrids can be baked after loading the map and by typing:

bakeLightGrids [<switches>...]
 limit[num] : max probes per BSP area (default 16384)
 bounce[num] : number of bounces or number of light reuse (default 1)
 grid( xdim ydim zdim ) : light grid size steps into each direction (default 64 64 128)

This will generate a .lightgrid file next to your .map file and it will also store a light grid atlas for each BSP area under env/maps/<path/to/your/map/>

Limit is 16384 by default and means the maximum number of light grid points in a single light grid. Quake 3 had one light grid that streched over the entire map and distributed lighting every 64 x 64 x 128 units by default. If the maps were too big then q3map2 made the default grid size broader like 80 x 80 x 144, 96 x 96 x 160 and so on until the maximum number of light grid points was reached.

The Quake 3 approach wouldn't work with Doom 3 because the maps are too big and it would result in up to 800k probes for some maps or the grid density would very coarse.

RBDOOM-3-BFG uses the bounding size of the BSP portal areas and puts smaller light grids into those BSP areas.

This way we can maintain a good grid density and avoid wasting storage because of light grid points that are in empty space.

But what is an Irradiance Volume or Light Grid exactly?

It tells each model or lit pixel how the indirect diffuse lighting is coming from any direction. The Probulator page by Yuri O'Donnell has some good examples:

Left: The captured view using a panorama layout. Right: The Diffuse lighting using Level 4 Spherical Harmonics aka Irradiance.

Now think of this for each of the grid points in RBDOOM-3-BFG. If a model is placed between those probes the lighting will be interpolated by the nearest 8 grid points similar like in Quake 3.

Quake 3 only stored the dominant light direction, the average light color of that direction and an ambient color term for each grid point. In RBDOOM-3-BFG you basically can have the diffuse lighting information for any world space direction instead. This is a way more advanced technique.

Image Based Lighting and Environment Probes

Environment probes supplement the light grids. While light grids provide diffuse lighting information the signal isn't good enough to provide plausible specular light reflections. This is where environment probes are needed.

If a level designer doesn't put any env_probe entities into a map then they are automatically distributed through the map using the BSP area bounds and placed in the center of them.

Environment probes can be computed after loading the map and by typing:


This will generate EXR files in env/maps/<path/to/your/map/>.

The environment probes use an octahedron encoding and the specular mipmaps are convolved using the Split Sum Approximation by Brian Karris [Epic 2013]. Convolving the environment probes is done on the CPU using the id Tech 5 multi threading code so it will consume all your available cores.

For artists this basically means if you increase the roughness in your material then you increase the mip map level of the environment probe it samples light from and it gets blurier.

Fallback for Missing Data

If you haven't downloaded the additional baked light data from the RBDOOM-3-BFG ModDB Page and just run RBDOOM-3-BFG.exe with the required DLLs (or you built it yourself) it will use an internal fallback. RBDOOM-3-BFG.exe has one prebaked environment probe that is compiled into the executable.

It's the light data from the Mars City 1 lobby in the screenshot above. Using this data for the entire game is inacurrate but a better compromise than using a fixed global light direction and some sort of Rim lighting hack like in version 1.2.0. The default irradiance / radiance data gives the entire game a warmer look and it fits for being on Mars all the time.

Some Examples of Indirect Lighting

Single spot light render with direct lighting only

Single spot light render causing indirect light bounce using the new irradiance light grid in RBDOOM-3-BFG combined with SSAO

Raytraced reference in Blender 2.83 with Cycles raytracing

Left: No global illumination. Ambient is pitch black like in original Doom 3. Right: Extra ambient pass for global illumination with r_forceAmbient 0.5.

Some examples that show additional environment lighting on all assets.


Left: Wrong original Blinn-Phong in sRGB gamma space. Right: Gamma correct HDR rendering in linear RBG + ACES Film Tonemapping

Screen Space Ambient Occlusion

r_useSSAO 1 darkens the corners of the scene and also removes too much ambient added by the Global Illumination.

Filmic Post Processing

If you enable it with r_useFilmicPostProcessing 1 then you play DOOM 3 BFG the optics of a Zack Snyder movie.

It adds chromatic abberation and filmic dithering using Blue Noise. The effect is heavy and is usually aimed in Film production to mix real camera footage with CG generated content.

Dithering demonstration: left side is quantized to 3 bits for each color channel. Right side is also only 3 bits but dithered with chromatic Blue Noise. The interesting fact about the dithering here is shown in the upper debug bands. The first top band is the original signal. The second shows just 8 blocks and if you dither the those blocks with Blue Noise then it is close to the original signal which is surprising.

TrenchBroom Mapping Support

The goal of the TrenchBroom support is to make mapping for RBDOOM-3-BFG as easy as for Quake 1.

Mapping for Doom 3 BFG using TrenchBroom requires an extended unofficial build that is bundled with the official RBDOOM-3-BFG 7z package. You can find the customized version under tools/trenchbroom/.

More information about this custom TrenchBroom and the source code is here:

Doom 3 BFG also requires some extensions in order to work with TrenchBroom. The Quake 1/2/3 communities already adopted the Valve 220 .map format in the BSP compilers and I did the same with dmap in RBDOOM-3-BFG.

TrenchBroom speficic Changes

  • idMapFile and dmap were changed to support the Valve 220 .map format to aid mapping with TrenchBroom
  • Added exportFGD [nomodels] console command which exports all def/*.def entityDef declarations to base/exported/_tb/ as Forge Game Data files. TrenchBroom has native support to read those files If the nomodels argument is not given then it will also export all needed models by entity declarations to base/_tb/ as Wavefront OBJ files.
  • Support angles keyword again for TrenchBroom like in Quake 3
  • Added cmd convertMapToValve220 <map>
  • Added cmd exportImagesToTrenchBroom which decompresses and saves all .bimage images to _tb/*.png files
  • Added cmd exportModelsToTrenchBroom which saves all .base|.blwo|.bmd5mesh models to _tb/*.obj files

General Notes

A short summary of the file layout:

Directory Description
RBDOOM-3-BFG/base/ Doom 3 BFG media directory ( models, textures, sounds, maps, etc. )
RBDOOM-3-BFG/neo/ RBDOOM-3-BFG source code ( renderer, game code for multiple games, OS layer, etc. )
RBDOOM-3-BFG/build/ Build folder for CMake
RBDOOM-3-BFG/tools/blender/ Blender scripts for level mapping (TBD in release packages)
RBDOOM-3-BFG/tools/trenchbroom TrenchBroom level editor customized for DOOM 3 and RBDOOM-3-BFG
RBDOOM-3-BFG/tools/darkradiant DarkRadiant level editor with an additional config for RBDOOM-3-BFG
RBDOOM-3-BFG/tools/runtimedeps Visual Studio C++ Redistributables if you have problems to start the engine or the tools
RBDOOM-3-BFG/tools/bfgpakexlorer BFG Resource File Manager by George Kalampokis aka Mr.GK

The GPL release does not contain any game data, the game data is still covered by the original EULA and must be obeyed as usual.

You must patch the game to the latest version.

You can purchase Doom 3 BFG Edition from GOG (DRM Free):

Or the game can be purchased from Steam (with DRM):


The Doom 3 BFG Edition GPL Source Code release does not include functionality for integrating with Steam. This includes roaming profiles, achievements, leaderboards, matchmaking, the overlay, or any other Steam features.

Bink Video playback

The RBDOOM-3-BFG Edition GPL Source Code release includes functionality for rendering Bink Videos through FFmpeg or libbinkdec.

Back End Rendering of Stencil Shadows

The RBOOM-3-BFG Edition GPL Source Code release includes functionality enabling rendering of stencil shadows via the "depth fail" method, a functionality commonly known as "Carmack's Reverse".

This method was patented by Creative Labs and has finally expired on 2019-10-13. (see for expiration status)


See for the GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007

ADDITIONAL TERMS: The Doom 3 BFG Edition GPL Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU GPL which accompanied the Doom 3 BFG Edition GPL Source Code. If not, please request a copy in writing from id Software at id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.

See for all parts of the code that are not covered by the GPL.

Getting the Source Code

This project's Git repository can be checked out through Git with the following instruction set:

> git clone --recursive

The parameter --recursive is only required if you want to build RBDOOM-3-BFG with Vulkan support.

Existing repositories can be updated manually:

> git submodule init
> git submodule update

Compiling on Windows

  1. Download and install the Visual Studio 2019 Community Edition.

  2. Download and install the latest CMake and make sure cmake.exe is added to your global or user PATH.

  3. Generate the VS2019 projects using CMake by doubleclicking a matching configuration .bat file in the neo/ folder. Recommended in this case is cmake-vs2019-64bit-windows10.bat

  4. Use the VS2019 solution to compile what you need: RBDOOM-3-BFG/build/RBDoom3BFG.sln

Optional if you want to use FFmpeg

  1. Download from

  2. Extract the FFmpeg DLLs to your current build directory under RBDOOM-3-BFG/build/

Compiling on Linux

  1. You need the following dependencies in order to compile RBDoom3BFG with all features:

    On Debian or Ubuntu:

     > apt-get install cmake libsdl2-dev libopenal-dev libavcodec-dev libavformat-dev libavutil-dev libswscale-dev

    On Fedora

     > yum install cmake SDL-devel openal-devel ffmpeg-devel

    On ArchLinux

     > sudo pacman -S sdl2 cmake openal ffmpeg

    On openSUSE

     > sudo zypper install cmake libSDL2-devel openal-soft-devel

    You don't need FFmpeg to be installed. You can turn it off by adding -DFFMPEG=OFF and -DBINKDEC=ON to the CMake options. It is enabled by default because the bundled libbinkdec is slow during development if compiled for Debug mode.

  2. Generate the Makefiles using CMake:

     > cd neo/
     > ./
  3. Compile RBDOOM-3-BFG targets with

     > cd ../build
     > make

Compiling on macOS

  1. Download and install Homebrew ( for single architecture builds or MacPorts ( for universal architecture builds on macOS Big Sur or later.

  2. You need the following dependencies in order to compile RBDoom3BFG with all features:

    > brew install cmake sdl2 openal-soft ffmpeg (for single arch libraries only)
    > sudo port install cmake libsdl2 +universal openal-soft +universal (for universal arch libraries)

    You don't need FFmpeg to be installed. You can turn it off by adding -DFFMPEG=OFF and -DBINKDEC=ON to the CMake options. For debug builds FFmpeg is enabled by default because the bundled libbinkdec is slow during development if compiled for Debug mode. For release, retail and universal builds FFmpeg is disabled and libbinkdec is enabled by default.

  3. Generate the Makefiles using CMake:

    For command line builds:

     > cd neo/
     > ./

    For Xcode builds:

     > cd neo/
     > ./	
     > ./ (universal build on macOS Big Sur / Xcode 12.2 or later)

    Depending on which package manager you install (Homebrew or MacPorts) you may need to change the openal-soft library and include paths specified in the cmake shell scripts. For single architecture builds (debug, release, retail) the default openal-soft paths are set for Homebrew on x86, while for universal builds the default paths are set for MacPorts on x86 or Apple Silicon. If you want to build using the single architecture shell scripts (debug, release, retail) on Apple Silicon, you will need to change the openal-soft paths from /usr/local/... to either /opt/homebrew/... (Homebrew) or /opt/local/... (MacPorts).

  4. Compile RBDOOM-3-BFG targets:

    For command line builds:

     > cd ../build
     > make

    For Xcode builds double click on RBDOOM-3-BFG/xcode-opengl-<buildtype>/RBDoom3BFG.xcodeproj and start the build. The generated Xcode project file is pre-configured with the correct targets and build settings.

Installation, Getting the Game Data, Running the Game

For 99% of all users:

  1. Download the newest version from the RBDOOM-3-BFG Mod DB Page


  1. There are usually 2 kinds of RBDOOM-3-BFG packages. The Full and the Lite version. With the Full version you have the Win64 binaries, the baked environment probes and lightgrid data for all BFG single player maps like RBDOOM-3-BFG- (6.18 GB download). The Lite version has the lite in the filename like RBDOOM-3-BFG- Those packages don't ship with the precomputed light data but have everything else needed to run the mod and the tools like the custom TrenchBroom build.

  2. Simply extract both packages over your C:\Program Files (x86)\Steam\SteamApps\common\Doom 3 BFG Edition\ directory and run RBDoom3BFG.exe.

This should also work fine with your GOG installation.

The following instructions are primarily intented for Linux users and all hackers on other operating systems.

To play the game, you need the game data from a legal copy of the game.

Currently this requires a Windows installer, whether that be the GOG installer or by using Steam for Windows.

Note: the original DVD release of Doom 3 BFG contains encrypted data that is decoded by Steam on install.

On Linux and macOS the easiest way to install is with SteamCMD: See the description on (macOS is directly below that) on how to install SteamCMD on your system. You won't have to create a new user.

Then you can download Doom 3 BFG with

> ./ +@sSteamCmdForcePlatformType windows +login <YOUR_STEAM_LOGIN_NAME> +force_install_dir ./doom3bfg/ +app_update 208200 validate +quit

(replace <YOUR_STEAM_LOGIN_NAME> with your steam login name) When it's done you should have the normal windows installation of Doom 3 BFG in ./doom3bfg/ and the needed files in ./doom3bfg/base/ That number is the "AppID" of Doom 3 BFG; if you wanna use this to get the data of other games you own, you can look up the AppID at

NOTE that we've previously recommended using download_depot in the Steam console to install the game data. That turned out to be unreliable and result in broken, unusable game data. So use SteamCMD instead, as described above.

Alternatively with the GOG installer, you can use Wine to install the game. See for details on how to install wine for Linux and macOS.

Once Wine is installed and configured on your system install Doom 3 BFG edition using the downloaded installers from

> wine setup_doom_3_bfg_1.14_\(13452\)_\(g\).exe

(there will be several .exe files from GOG, make sure all of them are in the same directory)

Once this is complete, by default you can find your Doom 3 BFG "base/" directory at ".wine/drive_c/GOG\ Games/DOOM\ 3\ BFG/base".

Note that you may want to add the following line to the bottom of the default.cfg in whatever "base/" directory you use:

  • set sys_lang "english"

This will ensure the game and its menus are in english and don't default to something else. Alternatives include:

  • set sys_lang "english"
  • set sys_lang "french"
  • set sys_lang "german"
  • set sys_lang "italian"
  • set sys_lang "japanese"
  • set sys_lang "spanish"


  1. Install Doom 3 BFG in Steam (Windows version) or SteamCMD, make sure it's getting updated/patched.

  2. Create your own Doom 3 BFG directory, e.g. /path/to/Doom3BFG/

  3. Copy the game-data's base dir from Steam or GOG to that directory (e.g. /path/to/Doom3BFG/), it's in /your/path/to/Steam/steamapps/common/DOOM 3 BFG Edition/base/ or, if you used SteamCMD or GOG installer with Wine, in the path you used above.

  4. Copy your RBDoom3BFG executable and the optional FFmpeg DLLs (if Windows FFmpeg enabled) to your own Doom 3 BFG directory (/path/to/Doom3BFG). Your Doom 3 BFG directory now should look like:


    • RBDoom3BFG (or RBDoom3BFG.exe on Windows)
    • avcodec-58.dll (Windows FFmpeg only)
    • avformat-58.dll (Windows FFmpeg only)
    • avutil-56.dll (Windows FFmpeg only)
    • swresample-3.dll (Windows FFmpeg only)
    • swscale-5.dll (Windows FFmpeg only)
    • base/
      • classicmusic/
      • _common.crc
      • (etc)
  5. On macOS the RBDoom3BFG executable will also search for game data within an app bundle's relative path ../Resources/base and, as a last resort, within the absolute path /Applications/ In addition, if you want the game to be standalone without dependencies on pre-installed dynamic libs, you can use macdylibbundler to bundle all external dylib dependencies into the app bundle (see or simply install via "brew install dylibbundler" or "sudo port install dylibbundler"). For example, the following command will copy all external dynamic library dependencies to the Contents/libs directory of the game's app bundle and adjust the rpaths within the RBDoom3BFG executable and copied dylibs.

     > dylibbundler -od -b -x -d

    After running dylibbundler you must re-sign the modified executable and dylibs if planning to run on Apple Silicon machines. The output of dylibbundler will indicate which dylibs (if any) require re-signing. This code signing step is not needed for x86-based Macs.

     > codesign -s - --force<modified-by-dylibbundler>.dylib
     > codesign -s - --force
  6. Run the game by executing the RBDoom3BFG executable.

  7. Enjoy

  8. If you run into bugs, please report them, see Bug Reports

New Console Variables and Commands

Gaming Related

Name Description
r_antiAliasing Different Anti-Aliasing modes
r_useShadowMapping [0 or 1] Use soft shadow mapping instead of hard stencil shadows
r_hdrAutoExposure [0 or 1] Adaptive tonemapping with HDR. This allows to have very bright or very dark scenes but the camera will adapt to it so the scene won't loose details. Default is 0
r_exposure [0 .. 1] Default 0.5, Controls brightness and affects HDR -> sRGB Rec. 709 exposure key. This is what you change in the video brightness options
r_useSSAO [0 .. 1] Use Screen Space Ambient Occlusion to darken the corners in the scene
r_useFilmicPostProcessing [0, 1] Apply several post process effects to mimic a filmic look

Modding Support

Name Description
dmap mapfile Command: Compiles a .map to its corresponding BSP .proc, Collision .cm files and Area Awareness System (AI navigation) .aas files. Just type dmap to list all options
dmap [glview] mapfile DMap option that exports the BSP areas and portals to .obj for debugging purposes
bakeEnvironmentProbes Command after loading a map. Captures all env_probe entities and stores them to disc
bakeLightGrids [<switches>...] <Switches> limit[num] : max probes per BSP area (default 16384) bounce[num] : number of bounces or number of light reuse (default 1) grid( xdim ydim zdim ) : light grid size steps into each direction (default 64 64 128)
exportScriptEvents Command: Generates a new script/doom_events.script that reflects all registered class events in the idClass C++ system. The gamecode still needs to be extended to add the original comments of the events
exportFGD [nomodels] Command: Exports all entity defs to base/_tb/*.fgd for usage in convertMapToValve220 <map>
exportImagesToTrenchBroom Command: Decompresses and saves all TB relevant .bimage images to base/_tb/*.png files
exportModelsToTrenchBroom Command: Saves all .base
exportEntityDefsToBlender Command: Exports all entity and model defs to exported/entities.json for usage in Blender
before loading a map.
exportMapToOBJ Command: Convert .map file to .obj/.mtl
postLoadExportFlashAtlas Cvar: Set to 1 at startup to dump the Flash images to exported/swf/
postLoadExportFlashToSWF Cvar: Set to 1 at startup to dump the Flash .bswf files as .swf (WIP)
postLoadExportFlashToJSON Cvar: Set to 1 at startup to dump the Flash .bswf files as .json. Can be reimported into the engine and imported into Blender for inspection
swf_show Cvar: Draws the bounding box of instanced Flash sprites in red and their names

convertMapToJSON mapfile | Command: Convert .map file to new .json map format with polygons instead of brushes. This was easy because the original .map format is only an array of entities and each entity has a simple dictionary for its values. This JSON format contains all level data and can be imported and exported to Blender without loosing any data. The new DMap can also compile map files with the .json suffix like regular maps.

Known Issues

  • Some lights cause shadow acne with shadow mapping
  • Some shadows might almost disappear due to the shadow filtering or look off ("Peter panning" problem)
  • [HDR] MSAA anti-aliasing modes don't work with HDR: Use SMAA with r_antiAliasing 1
  • [Vulkan] Vulkan backend is unfinished in general
  • [Vulkan] Shadow Mapping is not supported yet
  • [Vulkan] HDR is not supported yet and GI looks bad because it requires HDR and linear RGB color space
  • [Vulkan] Post processing and SMAA is not supported yet

Bug Reports

The best way for telling about a bug is by submitting a bug report at our GitHub bug tracker page:

If you want to report an issue with the game, you should make sure that your report includes all information useful to characterize and reproduce the bug.

  • Search on Google
  • Include the computer's hardware and software description ( CPU, RAM, 3D Card, distribution, kernel etc. )
  • If appropriate, send a console log, a screenshot, an strace ..
  • If you are sending a console log, make sure to enable developer output:

RBDoom3BFG.exe +set developer 1 +set logfile 2

You can find your qconsole.log on Windows in C:\Users<your user name>\Saved Games\id Software\RBDOOM 3 BFG\base\


Q: Why bother with DOOM-3-BFG in 2021? A: It is fun, period. Doom 3 is from 2004 but is still an impressive and entertaining game. In 2011 id Software added lot stuff from the development of Rage like its own Flash SWF and ActionScript 2 interpreter, proper support for gamepads and widescreens. It also combines the gamecode for Doom 3 and its missionpacks and runs it in a seperate thread and it has many multithreaded rendering optimizations. DOOM-3 and DOOM-3-BFG are some of the most transparent games available where you can open all files and inspect how the game was built. Unlike Quake 1-3, DOOM-3-BFG shipped with all level .map sources for 47 single player maps. There is plenty of stuff you can learn from it like solid run & gun core gameplay, AI, animations, client/server multiplayer, level design or simple and elegant engine design.

Q: Why bother with DOOM-3-BFG in 2022? A: The engine compiles faster than opening a project in Unity.

Q: Can I use this engine to make a commercial game? A: You can but don't bother me to give you free support and you probably should use Unreal Engine 4. I am a full time game developer and usually don't have time for any free support.

However some people already work on total conversions and there is a community on the id Tech 4 Discord server where you can ask questions and get some support:

Q: How do I know what code you've changed? A: Apart from the Git log diffs, you can look for // RB in the source code. Many other contributors commented their changes in the same way. I enforced the usage of Astyle in this project which also makes it alot easier to compare it against other ports of DOOM-3-BFG. Simply format the other ports with Astyle like I do in neo/astyle-code.bat and you can compare the code easily in WinMerge or KDiff3.

Q: How do I open the .resource files? A: If you install this package you can start the engine, open the console and run exec extract_resources.cfg. This will create a basedev/ folder next to your base/ folder with the indidividual files like .mtr materials or .def entity declarations.


Doom 3 BFG Edition with modern engine features (2021) like PBR, Baked Global Illumination, Soft Shadows, Cleaned up source, Linux and 64 bit Support








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