We are going to start with an age-old classic programming example, the Hello World program. If you have been programming for a while, you likely have done one or more of these already. There will be a twist though. We are going to use PRNs to randomize how we say Hello World.

Let's begin by setting up the project and completing the classic Hello World program. Start by launching Unity and creating a new project. You can name it Hello World. You can also set the perspective to 2D since most of what we do in this book will be in 2D.

Unity launch screen

Once the project is loaded, we will create a new Text GameObject in order to render our Hello World to the screen. On the top toolbar, select GameObject | UI | Text. This will place a new Canvas object with a Text object child onto the scene. An EventSystem is also placed in the Hierarchy panel but you can ignore this.

Canvas is mostly off screen and you have to zoom out quite a lot to see the full view. Rather than zooming out, let's adjust the Canvas to occupy the Main Camera view space, as follows:

This will adjust your Canvas object to fit the Main Camera view. You might still need to zoom out slightly to see the edges of Canvas.

Workflow to get the Canvas in Main Camera view

You might have noticed at this point that there is some text on the screen. In the lower left corner of the Canvas, it says New Text in a default grey that is difficult to see. Let's change that.

Select the Text object, which is a child of the Canvas object. First, we will change the position. In the Rect Transform component section:

The anchors are set to center so the Rect should snap to the center of the Canvas. Next, we'll change the size of the Rect so that we can make the text larger:

This will allow us to have much larger text. Note that if we had just tried to change the font size without changing the Rect size, the text would be clipped or would even vanish completely. Now let's get the text looking nice by going to the Text (Script) component section:

Now our text is nice and visible. At this point, you can select the text in the Text field and delete it. We are going to have our script write the text for us.

Finished canvas and text formatting

Let's start scripting by creating a new C# script. On the top toolbar, select Assets | Create | C# Script. This will create a new script in your Assets folder under the Project pane. You can name the script HelloWorld.cs.

Open the script in MonoDevelop or your favorite IDE. We are going to use the following Code Snip 1.1:

1 using UnityEngine;
2 using UnityEngine.UI;
3 using System.Collections;
4 
5 public class HelloWorld : MonoBehaviour {
6 
7   public Text textString;
8 
9   void Start () {
10     textString.text = "Hello World";
11  }
12 }

Let's take a look at what's happening in Code Snip 1.1:

That's all there is to it. Now, we just need to add the script to the scene. It doesn't matter which object you attach the HelloWorld.cs script to because we will declare the specific Text object the script acts on. To keep things organized, this way works well:

Now, you can press the play button, and you'll see Hello World in a large font:

Hello World program's result

That completes the Hello World program. However, that's not all that interesting. In order to give this classic programming example some new flair, let's add some randomness.

Using our Hello World example, we will add PRNs into the mix and give our program some procedurally generated text. We'll start by editing our current HelloWorld.cs script. The goal here is to randomly display one of a few variations of the Hello World text.

You can achieve this by creating an array of different strings and having Unity's Random method choose a number from 0 to the length of the array. You will use that PRN as the index of the string array. In this case, our array holds the Hello World string in a few different languages. So instead of telling the Text object to display Hello World, we will tell it to display the contents of the array at the PRN index.

Open the HelloWorld.cs script and make the following changes in Code Snip 1.2:

5 public class HelloWorld : MonoBehaviour {
6 
7   public string[] hellos = new string[4] {
      "Hello World", "Hola Mundo", "Bonjour Le Monde", "Hallo Welt"};
8 
9   public Text textString;
10
11  void Start () {
12    Random.seed = (int)System.DateTime.Now.Ticks;
13    int randomIndex = Random.Range (0, hellos.Length);
14    textString.text = hellos[randomIndex];
15  }
16 }

The changes in Code Snip 1.2 are as follows:

Head back into the Unity editor to see the changes. You should see the new Hellos field. If you expand it, then you will see all of the strings contained in the array. The script might also lose connection to the Text object. You can just drag and drop the Text object into the Text String field to reconnect it.

Hello World with PRNs program result

And that's it. You completed your first PCG capable program. Test it out by pressing the play button. You will randomly get one of the four Hello World strings displayed in the Game screen. There are only four choices so you might have to try a couple of times before you start seeing any variation.