Gabriel Gambetta

Introduction

In the first article of the series, we introduced the concept of an authoritative server and its usefulness to prevent client cheats. However, using this technique naively can lead to potentially showstopper issues regarding playability and responsiveness. In the second article, we proposed client-side prediction as a way to overcome these limitations.

The net result of these two articles is a set of concepts and techniques that allow a player to control an in-game character in a way that feels exactly like a single-player game, even when connected to an authoritative server through an internet connection with transmission delays.

In this article, we’ll explore the consequences of having other player-controled characters connected to the same server. read more »

Introduction

In the first article of this series, we explored a client-server model with an authoritative server and dumb clients that just send inputs to the server and then render the updated game state when the server sends it.

A naive implementation of this scheme leads to a delay between user commands and changes on the screen; for example, the player presses the right arrow key, and the character takes half a second before it starts moving. This is because the client input must first travel to the server, the server must process the input and calculate a new game state, and the updated game state must reach the client again.

Effect of network delays

In a networked environment such as the internet, where delays can be in the orders of tenths of a second, a game may feel unresponsive at best, or in the worst case, be rendered unplayable. In this article, we’ll find ways to minimize or even eliminate that problem. read more »

Introduction

This is the first in a series of articles exploring the techniques and algorithms that make fast-paced multiplayer games possible. If you’re familiar with the concepts behind multiplayer games, you can safely skip to the next article – what follows is an introductory discussion.

Developing any kind of game is itself challenging; multiplayer games, however, add a completely new set of problems to be dealt with. Interestingly enough, the core problems are human nature and physics! read more »