Chapter 20: Creating User Interfaces

Creating user interfaces (UI) is a crucial part of developing games with Unity. The UI is the way players interact with the game. It is through it that players receive information about the state of the game, such as score, life, map, inventory and many others. The UI also allows players to control the game, through buttons, menus and other interactive controls.

1. Basic UI Concepts

Before we start building our UI, it's important to understand some basic concepts. In Unity, the UI is built using a system of 'Canvas' and 'UI Elements'. Canvas is like a canvas where we place our UI elements. We can have multiple Canvases in our game, each with its own UI.

UI elements are objects that we place on our Canvas. These can be buttons, texts, images, sliders and many others. Each UI element has properties that we can adjust to change its appearance and behavior.

2. Creating a Canvas

The first step to creating our UI is to create a Canvas. To do this, we go to the 'GameObject' menu and select 'UI -> Canvas'. This will create a new Canvas in our scene.

Canvas has several properties that we can adjust. The most important one is 'Render Mode'. This property determines how the Canvas is rendered. We can choose between 'Screen Space - Overlay', 'Screen Space - Camera' and 'World Space'. The choice depends on how we want our UI to be presented.

3. Adding UI Elements

Now that we have our Canvas, we can start adding UI elements. To do this, we go to the 'GameObject' menu and select 'UI'. Here we find a list of all the UI elements we can add. Let's start by adding text.

We select 'UI -> Text' and a new text element will be added to our Canvas. We can adjust text properties to change its appearance. We can change the font, size, color, alignment and many others.

4. Interactivity

UI is not just about presenting information, but also about allowing players to interact with the game. To do this, we can add interactive elements to our UI, such as buttons.

To add a button, go to the 'GameObject' menu and select 'UI -> Button'. This will add a new button to our Canvas. We can adjust the button's properties to change its appearance. Additionally, we can add an 'OnClick' event to the button. This event will be triggered when the button is clicked.

5. Layouts

When we have many UI elements, it can be difficult to organize them effectively. For this, Unity offers several layout components that we can use. These components automatically adjust the size and position of our UI elements for us.

For example, we can use the 'Grid Layout Group' component to organize our UI elements in a grid. To add this component, we select our Canvas, go to the 'Inspector' panel and click on 'Add Component -> Layout -> Grid Layout Group'.

In summary, creating user interfaces is an important part of developing games with Unity. With the Canvas and UI Elements system, we can create rich, interactive UIs that enhance the player experience.