wowdecomp

A C++ decompilation of the World of Warcraft 3.3.5a client (Wow.exe, build 12340, June 2010).

Join the discord for other clients and to show off some cool stuff you build.

https://discord.gg/DsZMGUD8aT

Every function is reconstructed from the original binary and keeps the address it came from in an // OFFSET: tag, so each one can be compared against the original. The source tree follows the layout of the original client (Engine/Source/<Module>, WoW/Source/<Module>, original file names).

The client builds 64-bit only.

Progress

The percentages below measure how much of the original binary has a counterpart in this source tree. They do not say how much of the game works, and the missing part is not missing gameplay: the client builds into a complete executable and the game is 100% playable. Bugs could still be hiding, though; a ported function can behave differently from the original.

Measured against the 12340 binary on 2026-10-15. A function counts as ported when its address is tagged in the source.

	Ported	Total	Share of the original
Functions	24,515	27,157	90.3%
Code bytes	5,270,186	5,656,573	93.2%

The total leaves out 658 functions that IDA identifies as compiler library code and 132 import thunks. Most of the untagged remainder is code the build gets elsewhere: compiler-generated code (static initializers, template instances) that our compiler emits on its own, C runtime helpers, and third-party libraries that are linked from their upstream sources instead of being decompiled (FreeType, zlib, PCRE, parts of FMOD Ex).

Requirements

• Windows 10 or 11
• Visual Studio 2022 with the Desktop development with C++ workload (MSVC v143 and a Windows SDK)
• CMake 3.10 or newer (the one that ships with Visual Studio works)
• A World of Warcraft 3.3.5a (12340) client. No game data is included in this repository.

Building

From a Developer PowerShell or any shell with cmake on PATH:

git clone https://github.com/SatyPardus/wowdecomp.git
cd wowdecomp

cmake -S . -B build/x64 -G "Visual Studio 17 2022" -A x64
cmake --build build/x64 --config Release --target WowClient --parallel

In-source builds are refused, so keep the build directory separate (build/ above).

The client is written to bin/Win/:

Target	Executable
WowClient	WowClient64.exe
Wow	Wow64.exe

WowClient is the client with a crash logger: it opens a console window and writes WowClient_crash.log when the client crashes. Wow is the same client without it. You can also turn the logger off in WowClient with -DWOWCLIENT_CRASH_LOG=OFF.

Linux (native)

The client also builds as a native Linux x86_64 executable. It renders through the Direct3D 9 device on Vulkan, using dxvk's native libdxvk_d3d9.so on an SDL2 window, and falls back to the OpenGL device when no Vulkan driver is found (SET gxApi "OpenGL" picks it by hand). Sound goes through FMOD Ex's SDL2 output, and the Windows platform sources are replaced by the Linux/ ones next to them. Requirements: clang, lld, CMake, Ninja, SDL2, the OpenGL headers and xvidcore, plus a Vulkan driver to run it. On Debian/Ubuntu:

sudo apt-get install clang lld cmake ninja-build libsdl2-dev libgl-dev libxvidcore-dev

cmake -S . -B build/linux -G Ninja -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
cmake --build build/linux --target Wow

The client is written to bin/Linux/Wow64, with libdxvk_d3d9.so next to it (CMake downloads the pinned dxvk release at configure time, the d3d9 headers are in ThirdParty/dxvk-native). Copy the Data folder of your 3.3.5a client next to it; file names are matched case-insensitively, so the folder can be copied as-is. Registry settings are kept in ~/.config/wowdecomp/registry.ini.

Cross compiling (Linux and macOS from any host)

Tools/Cross/cross.py builds the Linux and macOS clients with clang, lld and Ninja from Windows (or any other host). It needs Python 3, Git, CMake, LLVM (clang, lld, llvm-ar) and 7-Zip on the PATH. Ninja is taken from the PATH or from a Visual Studio install.

python Tools/Cross/cross.py sysroot linux    # Debian bookworm headers and libraries into .cross/linux-x86_64
python Tools/Cross/cross.py sysroot macos    # SDK submodule (sparse), SDL2.framework and xvidcore into .cross/macos

python Tools/Cross/cross.py build linux
python Tools/Cross/cross.py build macos-arm64
python Tools/Cross/cross.py build macos-x86_64

python Tools/Cross/cross.py package macos    # both Mac builds merged into a universal app, bin/Wow64-mac.tar.gz

The macOS SDK is the ThirdParty/macos-sdk submodule. It is marked update = none because the repo holds every SDK since 10.1, so git submodule update --init skips it and sysroot macos checks out only MacOSX26.5.sdk. On Windows that checkout needs symlink support (Developer Mode). Build trees go to build/cross-<name>/. The toolchain files are in cmake/toolchains/. Mac bundles go to bin/Mac-arm64/ and bin/Mac-x86_64/.

Options

CMake option	Default	Effect
WOWDECOMP_DISABLE_SIGNATURE_CHECKS	OFF	Skip the MPQ file and .toc.sig signature checks, so modified game data and interface files load
WOWCLIENT_CRASH_LOG	ON	Build WowClient with the crash logger
WOWCLIENT_FREEZE_DETECTOR	ON	64-bit WowClient force-crashes on the main thread when it hangs, so the dump shows where it was stuck. The WOWCLIENT_FREEZE_SECONDS env var changes the 10 second limit, 0 turns it off
WOWCLIENT_OUTPUT_OVERRIDE	empty	Name the WowClient executable something other than WowClient64

Running

1. Copy the Data folder of your 3.3.5a client into bin/Win/, so you have bin/Win/Data/.
2. Point Data/<locale>/realmlist.wtf at the server you want to connect to.
3. Start bin/Win/WowClient64.exe (or Wow64.exe).

Layout

Path	Contents
Engine/Source/	Engine modules: Storm, Gx (Direct3D 9 / OpenGL), Model2, Frame/FrameXML UI, SoundEngine, Lua, ...
WoW/Source/	Game modules: objects, world rendering, UI, networking, database, glue screens
WoW/Common/	Code shared by the game modules
ThirdParty/	Libraries linked from their upstream sources
Tools/WowClient/	The WowClient executable target
Tools/XvidDecoder/	x64 movie decoder that replaces the original 32-bit DivxDecoder.dll

Special thanks

• binana
• thunderbrew
• whoa
• TOMRUS, for the initial IDB
• Everyone who has reported bugs so far
• The WoW modding community