gMod/CLAUDE.md

gMod

A 32-bit Windows DLL that hooks Direct3D 9 to load texture mods for Guild Wars. Continuation of uMod. Integrated with GW Launcher and Daybreak.

Project structure

• header/ — header files (D3D9Hooks, D3D9State, Defines, Error, Main, Utils)
• source/ — implementation files (D3D9Hooks.cpp, dll_main.cpp, Error.cpp)
• modules/ — C++23 module files (ModfileLoader, ModfileLoader_TpfReader, TextureClient, TextureFunction)
• TpfConvert/ — standalone utility to fix broken .tpf files
• cmake/ — CMake helper scripts
• build/ — CMake build tree (generated, ignored)
• bin/ — compiled output (generated, ignored)

Build

Requires Visual Studio 2022, CMake 3.29+, and vcpkg — all via the VS 2022 Developer PowerShell.

cmake --preset=vcpkg
cmake --open build
# then compile inside Visual Studio, or:
cmake --build build --config Release

• Target: 32-bit only (-A Win32 / CMAKE_GENERATOR_PLATFORM=win32)
• Standard: C++23
• Output: bin/ (gMod.dll, TpfConvert.exe)
• Version: set in CMakeLists.txt (VERSION_MAJOR/MINOR/PATCH/TWEAK)

Key dependencies (via vcpkg)

• minhook — D3D9 function hooking
• libzippp / libzip / zlib — reading .tpf/.zip mod files
• directxtex — texture format conversion
• Microsoft.GSL — Guidelines Support Library

How it works

1. dll_main.cpp — DLL entry point, hooks d3d9.dll via MinHook
2. D3D9Hooks.cpp — intercepts Direct3DCreate9 and IDirect3DDevice9 methods
3. ModfileLoader — reads modlist.txt, loads .tpf/.zip mod archives
4. TextureClient / TextureFunction — matches and replaces textures by hash at runtime

Notes

• Must be injected before d3d9.dll loads, or renamed to d3d9.dll in the GW folder
• Reshade > 5.0.1 causes glitches; recommend 5.0.1 or 4.9.1
• modlist.txt contains full paths to .tpf/.zip mod files, one per line