Book Image

Unreal Development Kit Game Programming with UnrealScript: Beginner's Guide

By : Rachel Cordone
Book Image

Unreal Development Kit Game Programming with UnrealScript: Beginner's Guide

By: Rachel Cordone

Overview of this book

Unreal Development Kit is the free edition of Unreal Engine—the largest game engine in existence with hundreds of shipped commercial titles. The Unreal Engine is a very powerful tool for game development but with something so complex it's hard to know where to start.This book will teach you how to use the UnrealScript language to create your own games with the Unreal Development Kit by using an example game that you can create and play for yourself. It breaks down the UnrealScript language into easy to follow chapters that will quickly bring you up to speed with UnrealScript game programming.Unreal Development Kit Game Programming with UnrealScript takes you through the UnrealScript language for the Unreal Development Kit. It starts by walking through a project setup and setting up programs to write and browse code. It then takes you through using variables, functions, and custom classes to alter the game's behavior and create our own functionality. The use and creation of Kismet is also covered. Later, using replication to create and test multiplayer games is discussed. The book closes with code optimization and error handling as well as a few of the less common but useful features of UnrealScript.
Table of Contents (18 chapters)
Unreal Development Kit Game Programming with UnrealScript
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Time for action – Other variable errors


There are a few more errors we need to take a look at before we move on. These ones have to do with the declaration and use of variables.

  1. Let's take a look at this PostBeginPlay function:

    simulated function PostBeginPlay()
    {
        local int Int1, Int2;
    
        Int1 = 3;
        Int2 = 5;
        Int1 + Int2;
    }
  2. If we try to compile that, we'll get this error message:

    [0003.77] Error: R:\UDK\UDK-AwesomeGame\Development\Src\BrokenGame\Classes\BrokenActor.uc(11) : Error, ';': Expression has no effect
  3. The source of that error is in this line:

        Int1 + Int2;

    We're not assigning the result of that to any variable, and we're not using it as a comparison or anything like that. If we wrote it like the following we wouldn't get the error:

    Int1 = Int1 + Int2;

    Not something you'd come across often, but it's good to know what the error message means.

  4. You would also get the same error message if a function parameter had the same name as another function, and you tried calling that function...