Unity 3.x Game Development Essentials: If you have an idea for a game but lack the skills to create it, this book is the perfect introduction. There’s lots of handholding through all the essentials, culminating in the building of a full 3D game.

As Unity comes in two main forms—a standard, free download and a paid Pro developer license, we'll stick to using features that users of the standard free edition will have access to.

If you're launching Unity for the very first time, you'll be presented with a Unitydemonstration project. While this is useful to look into best practices for the development of high-end projects, if you're starting out, looking over some of the assets and scripting may feel daunting, so we'll leave this behind and start from scratch!

In Unity go to File | New Project and you will be presented with the Project Wizard (Mac version shown); from here select the Create New Project tab .

Click the Set button and choose...

To create a simple environment, in which to prototype some game mechanics, we'll begin with a basic series of objects with which to introduce gameplay that allows the player to aim and shoot at a wall of primitive cubes.

When complete, your prototyping environment will feature a floor comprised of a cube primitive, a main camera through which to view the 3D world and a Point Light setup to highlight the area where our gameplay will be introduced. It will look something like this:

To take your first steps into programming, we will look at a simple example of the same functionality in both C Sharp(C#) and Javascript, the two main programming languages used by Unity developers. It is also possible to write Boo based scripts, but these are rarely used outside of those with existing experience in that language.

To begin, click the Create button on the Project panel, then choose either Javascript or C# Script.

Your new script will be placed into the Project panel named NewBehaviourScript, and show an icon of a page with either JS or C# written on it. When selecting your new script, Unity offers a preview of what is in the script already, in the view of the Inspector, and an accompanying Edit button that when clicked will launch the script into the default script editor—Monodevelop. You can also launch a script...

To actually use these variables to move an object, we will use the Translate command. When implementing any piece of scripting, you should make sure you know how to use it first.

Translate is a command which is part of the Transform class: http://unity3d.com/support/documentation/ScriptReference/Transform.html.

This is a class of information that stores the position, rotation, and scale properties of an object, and also functions that can be used to move and rotate the object.

The expected usage of Translate is as follows:

Transform.Translate(Vector3);

The use of Vector3 here means that Translate is expecting a piece of Vector3 data as it's the main argument—Vector3 data is simply information that contains a value for the X, Y, and Z coordinates; in this case coordinates to move the object by.

In Unity you can play test at any time, provided there are no errors in your scripts. If there are, Unity will ask you to fix all errors before allowing you to enter the Play Mode.

Once all errors are fixed—this will be signified by an empty or cleared Console bar at the bottom of the Unity interface. The Console bar represents the most recent entry into the Unity console. You can check this by choosing Window | Console (shortcut Ctrl + Shift + C [PC] Command-Shift + C [Mac]) from the top menu. All the errors will be listed in red, and double-clicking on the error will take you to the part of the script that will be causing the issue described. Most errors are often a forgotten character or simple misspelling, so always double check what you have written as you go.

If your game is free of errors, click the Play button at the top of the screen to enter the Play Mode. You will now be able to move the MainCamera object around by using the arrow keys—Up, Down, Left, and...

As we wish to fire this projectile when the player presses a key, we do not want the projectile to be in the scene by default, but instead want it to be stored and created when the key is pressed. For this reason we will store the object as a prefab, and use our script to instantiate (that is, create an instance of) it at the precise moment a key is pressed.

Click the...

Now within this IF statement—meaning after the opening { and before the closing }, put the following line:

C#:

Rigidbody instance = Instantiate(bullet, transform.position, transform.rotation) as Rigidbody;

Javascript:

var instance: Rigidbody = Instantiate(bullet, transform.position, transform.rotation);

Here we are creating a new variable named instance. Into this variable we are storing a reference to the creation of a new object that is of type Rigidbody.

The Instantiate commands requires three pieces of information namely, Instantiate(What to make, Where to make it, a rotation to give it);

So in our example, we are telling our script to create an instance of whatever object or prefab is assigned to the bullet public member variable and that we would like it to be created using the values of position and rotation from the transform component of the object this script is attached to—the Main Camera. This is why you will often see transform.position written...

Congratulations! You have just created your first Unity prototype.

In this chapter, you should have become familiar with with the basics of using the Unity interface, working with Game Objects, components, and basic scripting. This will hopefully act as a solid foundation upon which to build further experience in Unity game development.

Now you might want to relax a little and take time to play your prototype or even create one of your own based on what you have learned. Or you may just be eager to learn more; if so, keep reading!

Let's move on to the main game of this book, now that you are a little more prepared on some of the basic operations of the Unity development.

In the next chapter, we will begin to create a game called Survival Island. In this, you will learn how to use the Terrain tools to create a tropical island, complete with its own volcano! Once you have created your island, you'll add a player character prefab and take a stroll around your newly created tropical paradise...