In the previous chapter, we saw that 2D objects in Unity are Sprites. However, we didn't mention how to import them into the scene.

The easiest way to bring your Sprites into the scene is to drag and drop them from the Project panel into the Scene view. Unity will automatically create a new game object with the same name of the Sprite along with a Sprite Renderer attached. We have already covered this component in the previous chapter. Since we will not use Sorting Layers (as we decided in the previous chapter), we don't need to change any settings when dragging a new Sprite into the scene.

Another way to add Sprites to the scene is by right-clicking on the Hierarchy panel and then 2D Object | Sprite. However, in the Sprite Renderer, you need to specify which Sprite to use.

Let's bring the Pink_Sprinkle Sprite into our scene (you can find it in the Graphics/projectiles folder within the projectiles_sheet_01 file). It appears like this in the Scene view:

Since Sprites are also GameObjects...

Each game object can have a parent. This means that the game objects will move, rotate, and scale along with its parent.

I could use many words to explain this concept, but there are things which videos can explain better than words. As such, there is a very short video explaining, The Hierarchy and Parent-Child relationships at: https://unity3d.com/learn/tutorials/topics/interface-essentials/hierarchy-and-parent-child-relationships.

I recommend that you to watch it before you continue reading this book. I'll wait for you here.

Every game object in Unity has a position, but a position needs a reference frame (more about reference frames later in Chapter 5, The Secret Ingredient Is a Dash of Physics). In particular, Unity offers two ways to see (and set) coordinates:

You can easily switch between the two coordinates with a toggle in the upper-right part of the Unity interface, as shown in the following screenshot:

As shown in the preceding screenshot, they are both toggles, but the one to switch between world and local coordinates is the one on the left. At the moment, it is selected to be on Global, which means on world coordinates.

In the previous chapter, we decided to use Z-Buffering instead of Sorting Layers. However, we need to decide which elements of our game will be in the foreground compared to the others.

In addition, it is important to keep in mind how the camera is set. Select Main Camera, which should be the only camera in the scene. This is what the Inspector should look like:

As you can see, by default, its Z value on the the position is set to -10. This means you cannot have any greater negative values (that means smaller than -10) in the Z value of a Sprite, otherwise it will not be rendered. For our purpose, -10 is perfect, and we will stick with it.

Next, we need to assign a Z value to all the elements that we have. We can start to place the map in the background, by assigning the lowest depth (maximum Z value) that we have in mind; in this case it's zero.

Then, we would like to have the enemies. Therefore, we can set their Z value to -1. After them, the...

We are finally ready to place the 2D map in our scene.

In the previous chapter, we have set the resolution to 16:9. Therefore, the maps that we will find in our packages are ready to use.

Let's start by dragging the sugar_mountain_map Sprite from the Graphics/maps folder into our scene. We need to place it in (0,0,0). Please note that the z axis is set to zero.

It is a perfect map for what we need. For example, on the left side, there is the beginning of the path that the sweet-tooth pandas will follow. At the end of the path, there is the Sugar castle that the player needs to protect. Furthermore, there is enough space at the top to implement our user interface in Chapter 3, Communicating with the Player - the User Interface.

The next step is to modify the camera settings. What we want to do is to fit the entire map in the Camera view. To achieve this, just modify the Size properties to 22.5 as shown here:

As a result, our map will be perfectly centered in the Camera view....

If you already have in mind what are you going to do, it's good to set everything up at the beginning. In particular, Unity has some labels that can be given to game objects. These are layers and tags. Unity uses these two properties to discriminate amongst certain kinds of game objects.

By default, some of them are already defined, but we need a few more for our project. From the toolbar menu, we can access the layers and tags settings by navigating to Edit | Project Settings | Tags and Layers. As a result, the Inspector should now look like the following screenshot:

Let's expand the Tags menu, as follows:

To add a new tag, just press on the + button in the bottom-right corner. We need to add two tags, respectively Enemy and Projectile, as shown in the following screenshot:

In fact, we will need...

When the scene begins to fill up with objects, some of these objects might become complex. By complex, I mean with a lot of components and children. If we need to use many of them in the game and maybe change all of them at once, Unity offers the possibility to create a Prefab.

As the name suggests, it is an object already assembled with all the necessary components and ready to be placed in the scene. The advantage is the possibility to reuse it often and to change all its instances quickly.

To keep our project organized, let's create a folder named Prefabs, if we haven't done so yet. Inside the folder, right-click and then select Create/Prefab. You can name it as you want, but for this book, let's stick with Pink_Sprinkle_Projectile_Prefab.

We already have the sprinkle in the scene, so from the Hierarchy panel, drag it into...

You should already know about the game view, but there might be some new types of functionality that you didn't know about before. So, a short recap might be useful, before we move on in our journey.

First of all, we have our three main buttons, which you should be very familiar with, as shown here:

The first is the play button, which makes your game run. The second button pauses the game, and allows you to tweak some settings. The last one makes your game run for one frame only.

In the top-left corner, we have the displays and the resolution tabs that we covered in the previous chapter. In the opposite corner (top-right), there are many different yet useful toggles, as shown in the following screenshot:

These are their functions:

Either you like math or not; however, it is a fact that it is required for game development. We don't have time to go through all the math behind this game, since it is required to have a complete toolset for game development. However, this section introduces you to some basic concepts that we will need for the rest of the book. In addition, it also makes some references to the official documentation so that you can learn a bit more about it.

If you feel confident with some of the following topics, you are free to skip them:

In this section, we will learn one of the toughest topics in game development! However, I strongly encourage you not to be scared, but try to practice a lot. As a result, you will be able to master every single detail of your game. And that is awesome!

In the Prefabs section, we created the Prefab for our sprinkle projectile. In this section, we will see how to make sprinkles move into the 2D space. In particular, we will learn how to create and use scripts in Unity for 2D game elements.