The Battle for Wesnoth

The Battle for Wesnoth is a self‑hosted, open‑source tactical strategy engine written primarily in C++14. It exposes a rich scripting layer through WML (Warcraft Markup Language) and Lua, allowing developers to author campaigns, units, and entire game states without touching the core codebase. From a technical standpoint, the engine is designed around an event‑driven architecture where game logic is decoupled from rendering and networking, making it straightforward to swap out modules or extend functionality.

• Core Engine: C++14, compiled with GCC/Clang/MSVC. The rendering pipeline uses SDL2 for cross‑platform windowing and OpenGL for accelerated sprite drawing. Audio is handled by OpenAL or SDL_mixer, depending on the build.
• Scripting: WML files describe maps, units, and campaign flow; Lua scripts provide procedural content generation and AI behaviors. The engine embeds a Lua interpreter (Lua 5.3) that exposes C++ APIs for game state manipulation.
• Networking: A lightweight, peer‑to‑peer protocol supports both local hotseat and online multiplayer. The networking stack is built on top of UDP with optional TCP fallback for reliability.
• Persistence: Saves are stored as XML/JSON blobs; the engine can serialize entire game states for replays or debugging. No external database is required, simplifying deployment.

• Modular Content: Developers can drop new maps, campaigns, or unit packs into the data/ directory; the engine auto‑loads them on startup.
• API Hooks: The Lua API exposes functions such as unit.move, terrain.set, and event.register. These can be used to create custom AI scripts or trigger in‑game events.
• Replay System: The engine records actions into a binary replay file, which can be played back or streamed to other clients for remote debugging.
• Custom UI: The GUI is built with a declarative XML layout system; developers can replace widgets or add new panels without recompiling.

• Self‑Hosting: The server component is a single binary (wesnoth-server) that listens on configurable ports. It requires no external services, making it ideal for LAN or cloud deployments.
• Scalability: Each server instance handles a single game session. To scale horizontally, deploy multiple instances behind a load balancer or use Docker Compose for isolated environments.
• Containerization: Official Docker images are available on GitHub Container Registry, and the project provides a Dockerfile that compiles from source. Containers expose ports 7777 (default) and 6666 for hotseat matchmaking.
• Cross‑Platform: Builds are available for Windows, macOS, Linux (via Flatpak or Snap), and even mobile ports on iOS/Android, ensuring that a self‑hosted instance can reach a wide audience.

• Plugin System: While not a traditional plugin framework, the engine’s modular loading of WML and Lua scripts effectively serves as plugins. Developers can ship entire campaign packs that override core assets.
• Webhooks & API: There is no native REST API, but the engine can be wrapped with a custom server layer that exposes JSON endpoints for matchmaking or telemetry.
• Community Mods: The open‑source nature has spawned a vibrant modding community. Popular mods like “Eras of the North” or “The Last Alliance” demonstrate how to package new content as downloadable archives that plug into the engine seamlessly.

• Documentation: The official docs cover engine internals, scripting references, and build instructions. The docs/ folder contains a Lua API guide and WML syntax cheatsheet.
• Community Support: Active forums, Discord, IRC, and a dedicated subreddit provide quick help for both engine bugs and modding questions.
• Licensing: GPLv2 ensures that any derivative work must remain open source, which is a strong incentive for developers who want to maintain control over their custom game logic.

• Educational Projects: Students can learn C++ and scripting by modifying the engine or creating new campaigns.
• Custom LAN Tournaments: Organizations can host private tournaments with tailored rulesets and automated AI opponents.
• Research in Game AI: The Lua API allows researchers to implement novel decision‑making algorithms and benchmark them against the built‑in AI.

• Performance: Hand‑optimized C++ core delivers low latency even on modest hardware, making it suitable for real‑time multiplayer.
• Flexibility: The dual scripting layers give developers fine control over game logic while keeping the engine stable.
• Zero‑Cost Hosting: No proprietary servers or cloud credits required; a single binary runs on any modern OS.
• Community‑Driven Content: A vast library of user‑generated campaigns and units reduces development time for new projects.

Overall, The Battle for Wesnoth offers a robust, extensible foundation for developers looking to build or host their own tactical strategy experiences without reinventing the wheel.