18. Gameplay Framework Classes in Multiplayer

Overview

In this chapter, you will learn where the instances of the gameplay framework classes exist in multiplayer. You'll also learn how to use the game state and player state classes, as well as some new concepts in the game mode, including match states. We'll also cover some useful built-in functionality that can be used in different types of games.

By the end of this chapter, you'll be able to use the game state and player state classes to store information about the game and about specific players that can be accessed by any client. You'll also know how to make the most of the game mode class and other related functionality.

Introduction

In the previous chapter, we covered Remote Procedure Calls, which allow the server and the clients to execute remote functions on each other. We also covered enumerations and Bi-Directional Circular Array Indexing.

In this chapter, we're going to take a look at the most common gameplay framework classes and see where their instances exist in a multiplayer environment. This is important to understand, so you know which instances can be accessed in a specific game instance. An example of this would be that only the server should be able to access the game mode instance, so if you were playing Fortnite, a player shouldn't be able to access it and modify the rules of the game.

We'll also be covering the game state and player state classes in this chapter. As the name implies, these store information about the state of the game and of each player that is playing the game. Finally, toward the end of this book, we'll cover some new concepts in the...

Gameplay Framework Classes in Multiplayer

Unreal Engine 4 comes with a gameplay framework, which is a set of classes that allow you to create games more easily. The gameplay framework does this by providing built-in common functionality that is present in most games, such as a way to define the game rules (game mode), and a way to control a character (the player controller and pawn/character class). When an instance of a gameplay framework class is created in a multiplayer environment, it can exist on the server, on the clients, and on the owning client, which is the client that has its player controller as the owner of that instance. This means that the instances of the gameplay framework classes will always fall into one of the following categories:

• Server Only: The instances of the class will only exist on the server.
• Server and Clients: The instances of the class will exist on the server and the clients.
• Server and Owning Client: The instances of the class...

Game Mode, Player State, and Game State

So far, we've covered most of the important classes in the gameplay framework, including the game mode, player controller, and the pawn. In this chapter, we're going to cover the player state, game state, and some additional concepts of the game mode, as well as some useful built-in functionalities.

Game Mode

We've already talked about the game mode and how it works, but there are a few concepts that haven't yet been covered.

Constructor

To set the default class values, you can use the constructor like so:

ATestGameMode::ATestGameMode()
{
  DefaultPawnClass = AMyCharacter::StaticClass();
  PlayerControllerClass = AMyPlayerController::StaticClass();
  PlayerStateClass = AMyPlayerState::StaticClass();
  GameStateClass = AMyGameState::StaticClass();
}

The preceding code lets you specify which classes to use when spawning pawns, player controllers, player states, and game...

Summary

In this chapter, you learned that the gameplay framework class's instances exist in some game instances, but not in others. Having that knowledge will help you understand which instances can be accessed in a particular game instance. You also learned the purpose of the game state and player state classes, as well as learning new concepts for the game mode and some useful built-in functionalities.

At the end of this chapter, you have made a basic but functional multiplayer shooter that can be used as a foundation to build upon. You can add new weapons, ammo types, fire modes, pickups, and so on, to make it more feature-complete and fun.

Having completed this book, you should now have a better understanding of how to use Unreal Engine 4 to make your own games come to life. We've covered a lot of topics in this book, ranging from the simple to more advanced. You started out by learning how to create projects using the different templates and how to use blueprints...