All of the projects in this book will be built using the Unity 3D game engine. Unity is a powerful, cross-platform 3D environment with a user-friendly development editor. It consists of an amalgamation of various modules for managing and rendering 3D objects, lighting, physics, animations, audio, and more. It is also widely used for developing 2D games; however, the only 2D-specific features we will use in a project are the screen-space user interface (UI). Each of the Unity modules has a programmer interface, or API, with a rich set of classes and functions, so the entire system can be accessed through scripts written in the C# programming language.

Unity provides a range of subscription and licensing options. For more details, see https://store.unity.com/. The basic Personal version is free to download and use, and is great for AR development. In fact, the Personal...

When opening Unity, you are given the choices to start a new project, open an existing project, or watch a getting started video, as shown here:

To get started, let's create a new 3D project. Name it AR_is_Awesome or whatever you'd like as shown ahead:

Fill in the name for your project and verify that the folder location is what you want. Ensure that 3D is selected. There is no need to select any extra asset packages at this time. Click on Create Project.

Your new project opens in the Unity Editor, as shown here in its default layout:

The Unity Editor consists of a number of non-overlapping windows, or panels, that may be subdivided into panes. Here's a brief...

One more object we haven't discussed yet that is essential for any Unity application is the Camera. Unity developers may often add a Main Camera to their project scene and not give it much more thought. But in AR, the camera is especially important.

Cameras are devices that capture and display the virtual world for the player. For rendering computer graphics, the camera's Pose (position and rotation transform), its rectangular Viewport and Field of View (FOV) together define how much of the scene is visible and rendered on the screen. The camera Pose is where the camera is pointing. The Viewport is like a rectangular window that we're looking through; anything outside the Viewport is clipped and not drawn. The Field of View defines the viewing angle. In regular video games, developers enjoy the option to modify any of these options to give the...

Now that you have Unity up and running on your development machine, the next step is to get the AR SDK imported into your Unity project. This section describes the Vuforia toolkit. If you do not want to use Vuforia, you can skip to the next section on getting and using ARToolkit.

Vuforia with Unity supports building AR applications for various platforms, including:

• Android smartphones and tablets, using Windows or macOS
• iOS iPhones and iPads, using macOS only
• Windows 10 devices, including HoloLens, via UWP-Universal Windows Platform

The current list of devices supported can be found at https://www.vuforia.com/Devices.

In deciding to use Vuforia, please be aware of its licensing terms and pricing policy. This is commercial software. It is free to download and develop in your projects, but there are usage and distribution limitations in the free version...

This section describes the ARToolkit SDK for augmented reality development (http://artoolkit.org/). If you don't want to use ARToolkit, you can skip this section.

ARToolkit is an open source software project. It is free to use both for the development and the distribution of your apps that use it. Unlike Vuforia, there are no license fees. As an open source project, the source code is available to anyone who wants to use it, read it, and even extend it. ARToolkit is owned by DAQRI, a prominent AR industry leader, and is free to use under a LGPL v3.0 license (see http://archive.artoolkit.org/artoolkit-licensing).

If you distribute an app built with ARToolkit, it needs to include an acknowledgement and license notice, for example, in an about box. ARToolkit has the distinction of being perhaps the first and continuously supported open source AR SDK...