Asobi Arena

A multiplayer top-down arena shooter built on Asobi game backend.

This project demonstrates how to build a game on Asobi: implement the asobi_match behaviour with your game logic, configure it as a game mode, and you have a fully featured multiplayer backend with auth, matchmaking, leaderboards, and more.

Try it

git clone https://github.com/widgrensit/asobi_arena.git
cd asobi_arena
make start

That's it. make start checks your environment, starts PostgreSQL, compiles, and launches the server on http://localhost:8084.

What if I'm missing something?

make start will tell you exactly what's missing and how to install it:

  ✗ Erlang/OTP not found
  ✓ Docker
  ✗ rebar3 not found

Missing dependencies. Install them with:

  # Option 1: mise (recommended)
  curl https://mise.run | sh
  mise install

Available commands

make start       # Check deps + start db + compile + run
make setup       # First-time setup (fetch deps, start db, compile)
make check-deps  # Just verify your environment
make db          # Start PostgreSQL only
make shell       # Interactive Erlang shell
make stop        # Stop PostgreSQL
make clean       # Remove build artifacts

Requirements

• Erlang/OTP 28+ and rebar3 (use mise or see .tool-versions)
• Docker and Docker Compose (for PostgreSQL)

Game Logic

The entire game is one module — asobi_arena_game.erl — implementing asobi_match:

Callback	Purpose
init/1	Set up arena state (empty players, no projectiles)
join/2	Spawn player at random position with 100 HP
leave/2	Remove player from state
handle_input/3	Process WASD movement + mouse aim/shoot
tick/1	Move projectiles, check collisions, apply damage
get_state/2	Return visible state for each player

The match server runs at 10 ticks/second and broadcasts state to all connected players via WebSocket.

Game Rules

• 800x600 arena, 90-second rounds
• WASD movement, point-and-click shooting
• 25 damage per hit, 100 HP per player
• Match ends when time runs out or one player remains
• Winner = most kills

Client SDKs

Connect with any of the Asobi SDKs:

• Unity demo — ready-to-play Unity client
• Godot
• Defold
• Dart / Flutter
• JavaScript
• Unreal

Configuration

Game mode registration in config/dev_sys.config.src:

{asobi, [
    {game_modes, #{
        <<"arena">> => asobi_arena_game
    }}
]}