Real-time networked racing with Rust Bevy

Aka zoop aka "Town Racer"

An exercise in using Bevy, GGRS & Rapier

Gameplay

• It's real-time multiplayer networked racing
• Supports deterministic collisions
• Works both natively and in a browser

Latest gameplay:

Initial gameplay:

Lobby

• Authenticate with a username
• Create a room with a fixed amount of players
• Join an existing room

Architecture

Racing engine:

• At the core we have a racing game engine based on Bevy zoop_engine
• The racing engine compiles to WASM and native target platforms
• It uses Rapier to implement deterministic physics
• It also uses Bevy GGRS to support real-time networked state synchronization
• There's some hacky code to support WebSockets instead of WebRTC (because I didn't want to learn Matchbox)

CLI:

• Then there's a CLI tool to start the racing engine zoop_cli
• It's also cross-platform and should work on any native target platform
• It accepts a room config (server URL, room, players)
• And then it can start the racing game engine

Server:

• There's a Rust Actix based web server zoop_server
• It has an HTTP endpoint to create a user with a random passphrase ("ticket")
• It has HTTP endpoints to
  • create a room
  • join a room
  • await room readiness
• It has a WebSocket endpoint to exchange peer-to-peer GGRS state sync messages

Launcher:

• There's a Rust Tauri based frontend launcher zoop_web/zoop_tauri
• It's a wrapper for rendering the JavaScript frontend either natively or in the browser
• It has shims to allow the frontend JavaScript to spawn a native racing engine instance

Frontend:

• There's a Next.js based frontend zoop_web
• It supports running the racing game engine in the browser using WASM
• It supports running the racing game engine as a native app through interop with the "Launcher"
• It has a view for authentication
• It has a view for room creation and joining
• It has a view for playing/spawning the racing game engine in a given room

Project structure

web/tauri - tauri i.e. launcher and interop for web
web - Next.js UI app i.e. launcher for engine
engine - bevy game app
server - actix server for networking

Development

• Start backend zoop_server with cargo run in zoop_server/
• Compile the engine for frontend with ./build_wasm.sh and ./copy_wasm.sh in zoop_engine/
• Start frontend web with cargo tauri dev in zoop_web

Notes

• You need to install various pre-requisites which are not documented as this was a hobby project.
• The code is somewhat awful as it was written to achieve a result and not to look good.
• The determinism is somewhat ok, but still breaks down in some cases
• There are too many footguns when using this combination of libraries together to achieve a production-grade game without being a real-time networking guru :(