Roguelite Dungeon Crawler

A roguelite dungeon crawler built without a game engine. Inspired by Children of Morta (dungeon + meta-progression) and Moonlighter (hub between runs).

Tech stack

Layer	Technology
Backend	Scala 3, http4s, Circe
Frontend	Svelte, TypeScript, Vite, HTML Canvas
Protocol	JSON over WebSocket
Database	SQLite (to be added later)
Testing	MUnit + munit-cats-effect

Project structure

roguelite/
  backend/    # Scala http4s server — authoritative game state
  frontend/   # Svelte + Canvas client — rendering and input only

Getting started

Backend

Requires: Java 17+, sbt 1.9+

cd backend
sbt run          # starts the server on ws://localhost:8080/ws
sbt test         # run all tests

Frontend

Requires: Node 18+

cd frontend
npm install
npm run dev      # starts Vite dev server on http://localhost:5173

The Vite dev server proxies /ws to localhost:8080, so both can run simultaneously without CORS issues.

Architecture

The server is the single source of truth. The client sends PlayerAction messages and receives full StateUpdate snapshots in response. No game logic lives on the client.

Client (Svelte)                  Server (Scala)
────────────────                 ──────────────────────────
User input
  → GameClient.send()
  → JSON PlayerAction   ──────→  WebSocketRouter
                                   → MessageProtocol.decodeAction()
                                   → StateMachine.transition()
                                       → new GameState
  ← JSON StateUpdate    ←──────  → MessageProtocol.encodeUpdate()
  → gameState (store)
  → UI re-renders