This project is an implementation of a tiny subset of Age of Empires II gameplay, written in TypeScript inspired by the classic scenario MicroMania.
Implemented features include:
- Single player and multiplayer
- Lobby system
- Configurable hotkeys
- Recorded games
- Spectating
- Attack move
- Formations
- Control groups
- Shift-queue
- Isometric map with terrain
- Static demo (no server component)
- Live demo (running server but may go offline)
The goal of this project is to create a new implementation of an extremely small subset of features provided by the genie engine. It uses the smx file format for assets and attempts to implement concepts like: attack frame delay, range, reload time, min/max range - available in the original engine.
The entire game state is represented as a single object. Any changes to the game state are made by mutating it with an action. The most frequently dispatched action is a "tick", which increments the game simulation.
The orchestration of state can happen locally for single player or be coordinated by the server. The server will receive actions that clients wish to dispatch, validate them and send them back to each connected client to run against their own local simulation.
This keeps all clients in sync (given the simulation remains totally deterministic), since even for their own actions they must wait for the action received by the server to commit them to the simulation (ie the order of actions relative to ticks is the same for all clients).
All the code (outside of the ./server and ./client folders) can be run on both the server and the
client. The server currently runs the game simulation, for the sole purpose of syncing the entire state
object to spectators that observe games in progress, but it could also store and send a buffer of actions
to achieve the same effect, if running many simultaneous game simulations became problematic.
In addition to the game state, each client has its own client state, which is information that is non-essential for other clients to recreate the game state. It may include things like, the units that are selected, the position of the mouse, control groups and the camera viewport. This object works in a similar way in that actions made by the client (panning the camera, clicking a unit etc.) are dispatched into a function which mutates the local state.
The renderer takes both the client state and the game state and produces the visual representation of both that is ultimately displayed to the user.
Since the game simulation runs at a low fixed number of ticks per second (20), the renderer will also estimate the framerate of the client and interpolate the position of on-screen items by the fraction of the tick each frame has progressed. This allows the game to run at the maximum fps supported by the display while maintaining the same deterministic game state across clients.
Age of Empires II © Microsoft Corporation. This repo was created under Microsoft's "Game Content Usage Rules" using assets from Age of Empires II, and it is not endorsed by or affiliated with Microsoft.