cotta

About

Cotta is a framework for building fast-paced multiplayer games in Java. It makes netcode easy and allows developers to deliver smooth gameplay experience almost regardless of network conditions.

It is well known that netcode is a hard part of game development, but there are not too many libraries for Java ecosystem. Cotta fills this gap.

For whom?

Cotta fits needs of Java game developers who build fast room-based multiplayer games:

• Shooters, be it top-down or first-person: those are games where instant input feedback on client is crucial, as well as lag compensation for hitscan weapons
• MOBAs, which are not very different from top-down shooters if we talk about responsiveness and smoothness
• Probably, fightings
• Twitchy multiplayer platformers

Documentation

• Quick start
• Effects
• Architecture overview
• User guide

Inspired by

• A GDC… No, THE GDC talk by Blizzard about Overwatch netcode
• Photon Quantum
• Glenn Fielder’s articles

Features

• Built-in Entity-Component-System engine
• Exact same simulation on Client and Server
• Reliable UDP
• Client-side prediction
• Lag compensation
• Linear interpolation for clients
• Server-side reconciliation
• Adapting to changing network conditions like latency spikes or packet loss

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