Code overview

This page is an orientation tour of the 1.13 source tree for new contributors. The code lives at github.com/1dot13/source — the direct continuation of the old SVN trunk after development moved to GitHub in 2022. Everything below is based on the current repository listing and its build files; where a directory's purpose is inferred from file names rather than stated documentation, the description is hedged accordingly.

If you want to compile the game first, see Building the game. For the wider project structure (repos, releases), see the development overview.

The repository at a glance

• Language: overwhelmingly C++ with a smaller amount of C (GitHub's statistics report roughly 34.8 MB of C++ against 3.6 MB of C), plus a little CMake and HTML. The top-level CMakeLists.txt sets the C++ standard to C++17.
• Build system: CMake (minimum version 3.20). The intended workflow is opening the folder in Visual Studio 2019 or newer, which detects the CMake configuration automatically; a preset template is copied on first configure. Toolchain files for clang and MinGW also exist under cmake/.
• Bundled binaries: several prebuilt .lib files are checked in at the repository root: binkw32.lib, SMACKW32.LIB, mss32.lib, fmodvc.lib, libexpatMT.lib, lua51.lib, lua51.vc9.lib and VtuneApi.lib. These are import/static libraries for middleware the engine links against — for example, Utils/Cinematics Bink.cpp plays the game's Bink videos, and sgp/ includes headers such as SMACK.H, Mss.h and fmod.h for the video/sound middleware. A comment in CMakeLists.txt notes that lua51.lib was built with the static MSVC runtime (/MT), which forces the whole project to use it too.
• Third-party source (as opposed to prebuilt binaries) lives under ext/ — see the directory table below.
• Other root files: README.md (install and Visual Studio setup steps), an .editorconfig, a developer task-notes file, and the project logo ja2v1.13.png.

File names contain spaces

This codebase predates modern conventions: many source files have spaces in their names (Soldier Control.cpp, Map Screen Interface Map.cpp, Auto Resolve.cpp). Quote paths accordingly when scripting around the tree.

Top-level directory map

The table lists every directory in the repository root (as of July 2026) with a short description. Descriptions are based on the file names inside each directory and the top-level CMakeLists.txt; treat them as a starting point, not a specification.

Directory	What it houses
Tactical/	The turn-based combat layer — by far the largest directory (237 files). Soldiers (Soldier Control.cpp, Soldier Profile.cpp), weapons and items (Weapons.cpp, Items.cpp), line of sight (LOS.cpp), action points (Points.cpp), squads, morale (Morale.cpp), vehicles, boxing, food/disease/drugs, the in-sector interface (Interface*.cpp), and dozens of XML_*.cpp files that load the Data-1.13\TableData XMLs (attachments, LBE, merc starting gear, merchants, …).
Strategic/	The campaign layer (119 files): map screen (mapscreen.cpp, Map Screen Interface*.cpp), assignments, auto-resolve, merc contracts, quests, town loyalty, Rebel Command (Rebel Command.cpp), mines and facilities, militia (Town Militia.cpp, MilitiaSquads.cpp, MilitiaIndividual.cpp), the strategic AI (Strategic AI.cpp, Queen Command.cpp, Reinforcement.cpp) and more XML_*.cpp data loaders.
TacticalAI/	The classic per-soldier tactical AI: AIMain.cpp, DecideAction.cpp, Attacks.cpp, Movement.cpp, Knowledge.cpp, FindLocations.cpp, plus creature and zombie variants (CreatureDecideAction.cpp, ZombieDecideAction.cpp).
ModularizedTacticalAI/	A newer, plan-based AI framework with its own readme.txt, coding style rules and Doxygen configuration. Its sources (AbstractPlanFactory.cpp, PlanFactoryLibrary.cpp, LegacyAIPlan.cpp, NullPlan.cpp, CrowPlan.cpp, …) appear to wrap the classic AI in exchangeable "plans".
TileEngine/	The isometric world engine: rendering (Render Dirty.cpp, Render Z.cpp), lighting and shadows, smoke and light effects, explosions, fog of war, smell, buildings, interactive tiles, exit grids and the radar screen.
Laptop/	The in-game laptop and its "websites": A.I.M. pages (AimMembers.cpp, AimHistory.cpp, …), Bobby Ray's shop (BobbyR*.cpp), and related screens.
Ja2/	The game shell: main menu, intro, splash and loading screens, credits, the help screen, game settings and the new-game options screen (GameSettings.cpp, GameInitOptionsScreen.cpp), Cheats.h, and the multiplayer lobby screens (MPHostScreen.cpp, MPJoinScreen.cpp, MPChatScreen.cpp, …). Also contains Res/ with the Windows resource file ja2.rc.
Editor/	The built-in Map Editor's code (Editor Taskbar Creation.cpp, EditorBuildings.cpp, EditorItems.cpp, Editor Undo.cpp, …). It is compiled into the editor executables via the JA2EDITOR preprocessor definition.
Multiplayer/	Networking for the multiplayer mode: client.cpp, server.cpp, network.h, transfer_rules.cpp, and a bundled raknet directory (the RakNet networking library).
sgp/	The lowest-level engine/platform layer: file access (FileMan.cpp), memory management (MemMan.cpp), video (DirectDraw Calls.cpp, DirectX Common.cpp), input and mouse handling, fonts, the button system, image loaders (STCI.cpp, PCX.cpp, PngLoader.cpp, impTGA.cpp), game library archive access (LibraryDataBase.cpp) and debugging utilities. sgp/sgp.cpp is the entry translation unit compiled into every executable.
Utils/	Assorted support code: Bink cinematics playback, music control, the INI reader (INIReader.cpp), encrypted file handling, event pump, popup boxes, progress bars, text utilities and localization helpers.
lua/	Bundled Lua 5.1 headers plus the binding layer (lua_state.cpp, lua_function.cpp, lua_class_interface.cpp); lua_strategic.cpp and lua_tactical.cpp appear to expose strategic- and tactical-layer functionality to scripts. See Lua scripting for the modder-facing side.
i18n/	Localized game text, one file per language (_EnglishText.cpp, _GermanText.cpp, _RussianText.cpp, …) plus _Ja25*Text.cpp variants for Unfinished Business, and string import/export helpers. Built once per language target.
ext/	Third-party libraries built from source: VFS/ (the bfVFS library — the engine behind the Virtual File System), libpng/, zlib/ and export/ (a ja2export utility). versions.txt pins the bundled versions: 7z(lzma) 9.22, utfcpp 2.3.4, libpng 1.2.50, zlib 1.2.8.
cmake/	Build helper scripts: CopyUserPresetTemplate.cmake (copies the CMakePresets.json template from cmake/presets/ into the repository root on first configure), ValidateOptions.cmake (checks the language/application choices), clang and MinGW toolchain files, and a presets folder.
wine/	A small static library (wine.cpp plus an include/ folder) linked into the game; based on the name it appears to hold Wine-related compatibility code.
.github/	GitHub Actions workflow definitions.

How the build fits together

The top-level CMakeLists.txt turns each major directory (Editor, Ja2, Laptop, ModularizedTacticalAI, sgp, Strategic, Tactical, TacticalAI, TileEngine, Utils) into a static library, then links them into executables. Two axes multiply:

• Applications: JA2, JA2MAPEDITOR, JA2UB, JA2UBMAPEDITOR. The map editor builds add the JA2EDITOR (and JA2BETAVERSION) preprocessor definitions; the Unfinished Business builds add JA2UB and JA2UBMAPS. Because these definitions change how the shared code compiles, every library is rebuilt per application (e.g. JA2UB_sgp).
• Languages: CHINESE, DUTCH, ENGLISH, FRENCH, GERMAN, ITALIAN, POLISH, RUSSIAN. Each application/language combination produces its own executable, e.g. JA2_ENGLISH.exe, with a matching i18n language library.

You pick which applications and languages to build (and where the output goes, via CMAKE_RUNTIME_OUTPUT_DIRECTORY) in your CMake configuration — the practical steps are on the building page. Debug builds additionally define JA2BETAVERSION, JA2TESTVERSION and DEBUG_ATTACKBUSY, mirroring the legacy MSBuild setup.

Where to start reading

Rough pointers for common kinds of changes. Expect to hop between directories — the layers include each other freely (the top-level CMake adds nearly every directory to the global include path).

You want to change…	Start in
Tactical/combat mechanics (weapons, shooting, items, soldier behavior)	Tactical/ — e.g. Weapons.cpp, Items.cpp, LOS.cpp, Points.cpp, Soldier Control.cpp, Overhead.cpp
How XML data files are read into the game	The XML_*.cpp files in Tactical/ and Strategic/ (e.g. XML_Attachments.cpp, XML_MercStartingGear.cpp, XML_Army.cpp)
Strategic/campaign behavior (assignments, militia, enemy army, quests)	Strategic/ — e.g. Strategic AI.cpp, Queen Command.cpp (the enemy army's garrisons and reinforcements), Assignments.cpp, Town Militia.cpp, Quests.cpp
A single 1.13 feature system	Often one aptly named file — e.g. Tactical/Morale.cpp for morale and merc opinions, or Strategic/Rebel Command.cpp for the whole Rebel Command layer
How INI settings reach the code	Ja2/GameSettings.cpp — LoadGameExternalOptions() reads Ja2_Options.ini into the global gGameExternalOptions; the same file also loads Skills_Settings.ini, CTHConstants.ini and APBPConstants.ini (via the CIniReader from Utils/INIReader.cpp)
Enemy tactical AI decisions	TacticalAI/ (DecideAction.cpp, AIMain.cpp); the plan framework in ModularizedTacticalAI/
Tactical UI (panels, cursors, item display)	Tactical/Interface*.cpp, Tactical/UI Cursors.cpp
Map screen UI	Strategic/Map Screen Interface*.cpp, Strategic/mapscreen.cpp
Laptop websites (A.I.M., Bobby Ray's)	Laptop/
Main menu, new-game options, game settings	Ja2/ (GameInitOptionsScreen.cpp, GameSettings.cpp)
Rendering, lighting, explosions on the map	TileEngine/
Low-level engine (files, input, video, fonts)	sgp/, plus Utils/ for support code
Map Editor behavior	Editor/ — see also the Map Editor page
Multiplayer/networking	Multiplayer/, plus the MP*Screen files in Ja2/ — see Multiplayer
Lua scripting hooks	lua/ — see Lua scripting
Translations / game text	i18n/ — _EnglishText.cpp is the master source for every English in-game string

Grep is your friend

With 35+ MB of C++, the fastest way to find the code behind a feature is usually searching for a string you see in-game (check i18n/_EnglishText.cpp for the text constant, then search for that constant), or for the matching INI/XML tag name.

Coding conventions

There is no single enforced style across the whole tree — most of it inherits the original Sirtech code plus two decades of patches. Two concrete anchors exist:

• The repository root contains an .editorconfig.
• ModularizedTacticalAI/readme.txt defines explicit rules for that directory: 4-space indents, no tabs, Doxygen-style comments, CamelCase classes with lowercase_function_names() and trailing-underscore members, no new globals or macros, and ISO C++ conformance. If you touch that directory, follow its readme.

For how to submit changes, see Contributing.

Legacy source-code documentation (SVN)

The old SVN server still hosts a Documents/1.13 Modding/Source Code/ folder with developer material that never moved to GitHub:

• ModularizedAI/html/ — the Doxygen-generated API documentation for the ModularizedTacticalAI framework. The in-repo readme.txt points to a Developer_Docs/ModularizedAI/html/index.html path that does not exist in the GitHub repository; this SVN copy is that documentation.
• Help/ — assorted developer notes: NewAttachmentSystem_NAS.txt, RenderOverheadMap.txt, Multiplayer_Explosive.txt, PNG_Images.txt, Use_CodePages.txt, VS_Logging.txt, and two "BigMapsProject" RTFs, among others.
• ToDos/ — old task notes.

The SVN server uses a self-signed certificate

Your browser or tools will warn about ja2svn.mooo.com's certificate. The content is historical reference material from the pre-2022 SVN era; the GitHub repository is the authoritative, current source.

Sources

• github.com/1dot13/source — repository root and per-directory listings retrieved via the GitHub API (July 2026)
• Top-level CMakeLists.txt of 1dot13/source (build structure, applications, languages, compile definitions)
• README.md of 1dot13/source (Visual Studio setup)
• ModularizedTacticalAI/readme.txt and ext/versions.txt from 1dot13/source
• Ja2/GameSettings.cpp and cmake/CopyUserPresetTemplate.cmake from 1dot13/source (INI file names and loading functions; preset template behavior)
• GitHub language statistics API for 1dot13/source
• SVN Documents/1.13 Modding/Source Code/ folder and its Help/ and ModularizedAI/html/ subfolders (fetched July 2026)