# Lightcone Arena

> A browser-based multiplayer arena FPS built on the Lightcone protocol — relativistic peer-to-peer netcode with no authoritative server. Rust/Bevy compiled to WebAssembly; the whole game runs in the page.

Lightcone is a peer-to-peer FPS engine with causal event ordering: instead of one server-owned timeline, each peer maintains its own valid local worldview, and events are ordered by causality (an event DAG with vector clocks) rather than a global clock. Conflicts between causally independent events are resolved deterministically by all peers — concurrent hits are tie-broken with blake3 — so there is no lag compensation, no server rewind, and no privileged reference frame. The current focus is railgun-only 1v1 sniper duels in the Cathedral map. This page loads the WASM game client; a WebSocket signaling server (at /signal) brokers peer connections, after which gameplay traffic is peer-to-peer over WebRTC or WebSocket transports.

## Pages

- [Play Lightcone Arena](https://arena.fps.network/): the game — loads the WASM client with menu options for Solo Duel, Private Match, and Find Match

## Key facts

- Built in Rust with Bevy 0.15, compiled to WASM to run in-browser (also builds natively).
- No authoritative server: peers exchange causally-ordered events via an event DAG with vector clocks; every peer's worldview is equally valid.
- Deterministic hit resolution — blake3 tiebreak for concurrent hits; a ShotContext captures the shooter's worldview.
- Default mode is RailgunDuel: 1v1, railgun only (0.8s hold-to-charge), 5-frag limit, 180s, on the Cathedral map. A Deathmatch mode pits you against 5 AI with all 5 weapons.
- 9 arena maps with procedural textures, bone-level hit detection (11 bones, swept-ray), 144 Hz fixed physics tick with visual interpolation, and fully procedural audio.
- The protocol crates (lightcone-protocol, lightcone-net) are engine-agnostic with zero Bevy dependency.