HoloLens Beginner's Guide

Jason Odom

• Verlag: Packt Publishing
• Jahr: 2017
• ISBN:
  9781786465467
• Auflage: 1
• Thema: Ciencia de la computación
• Thema: Realidad virtual

Create interactive and intuitiveness HoloLens applications with easeAbout This Book• Start developing immersive and interactive apps for Microsoft HoloLens • Explore the Windows Universal Development platform for HoloLens development• Leverage the full set of HoloLens sensors to create mesmerizing appsWho This Book Is ForIf you are a developer new to Windows Universal development platform and want to get started with HoloLens development, then this is the book for you. No prior experience of C# programming or of the.NET framework is needed to get started with this book.What You Will Learn• Write an app that responds to verbal commands• Communicate between devices in the boundaries of the UWP model• Create sounds in the app and place them in a 3D space• Build simple apps that display holograms• Interact with the physical environment while taking physical boundaries into accountIn DetailHoloLens revolutionizes the way we work and interact with the virtual world. HoloLens brings you the amazing world of augmented reality and provides an opportunity to explore it like never before. This is the best book for developers who want to start creating interactive and intuitive augmented reality apps for the HoloLens platform.You will start with a walkthrough of the HoloLens hardware before creating your first app. Next you will be introduced to the various HoloLens sensors and find out how to program them efficiently so that they can interact with the real world seamlessly. Moving on, you will learn how to create smart animations and add video overlay that implements real-time tracking and motion-sensing abilities to your HoloLens app. Finally, you will learn how to test your app effectively.Style and approachThis book takes a step-by-step tutorial-style approach. It will guide you through every step with practical examples and make sure that you are confident enough to create your own HoloLens app from scratch by the end of the book.

I am in Control

In this chapter, we will cover the ways we can interact with HoloLens using the input system. This device has been designed around three pillars of control: Gaze, Gesture, and Voice (GGV). Although traditional controllers, such as a keyboard, mouse, and even game controllers, will work with the HoloLens, in most cases, GGV should be the go-to solution for the problems that we, as developers, need to solve.

Before we get there, we will start using the HoloToolKit in this chapter. In order to be successful, we will need to look at a couple of related Unity design concepts that we will use repeatedly, such as prefabs and parent/child relationship.

As we collect user input, we need to show a change to let the user know that their input was received. To help facilitate this need, we will learn some of the basics of Unity's animation system. We will expand our knowledge of materials and learn about textures as well.

Prefabs

Imagine that you have been hired to build a holographic corporate team-building exercise for an upcoming weekend event. The idea is to create a scavenger hunt to find a cute robot and you have a large group of mean robots trying to stop everyone. The event is a gamified first-person shooter/scavenger hunt. The winning team will get the real robot to help in their office. It will be fun; let the team get some tension out and repair some troubled relationships in the company. From the word go, you will be using prefabs.

A prefab is a Unity asset type that acts as a blueprint or a template. In our preceding example, something as simple as the bullets for the weapons or as complex as the large collection of really mean robots that are trying to stop the entire company from achieving their goals could also be prefabs.

Fundamentally, a prefab is a hierarchical collection of GameObjects and their associated components. Using a parent/child relationship very similar to the file folder system of a computer. A developer can create a complex object made out of many objects, and then copy that object in memory. This is a process known as instantiation, but can easily be understood as cloning.

The benefit of this process is when you need to create 15 robots for a robot game, at any given time you will get more efficient use of memory. Without instantiation and prefabs, each of those robots will take up their own space in memory and potentially start to bog the system down. With this cloning process, these objects that acquire space of memory and therefore use far less memory.

Let's save the HelloWorld

First, we will need to ensure that we load the project from Chapter 2, HoloWorld. We will make a copy of the scene to save time; work smart, not hard, they say:

Let's look at the steps we will need to carry out:

1. Click on File on the main menu.
2. Click on Save Scene As....
3. Navigate to the Scenes folder.
4. Type Chapter2 into the File name field and click on the Save button.
5. Now, repeat steps 1-3.
6. This time, type Chapter3 into the File name field and click on the Save button.

If you complete all the preceding steps correctly, you should see Chapter3.unity across the top bar and Chapter3 directly under the Create menu in the Hierarchy panel:

Parent/Child relationship

Before we make our first prefab, a concept that is both useful and important is parentage. In our Hierarchy view, we can have GameObjects with other GameObjects attached to them in a Hierarchy. We call the primary objects as parents, and the secondary objects are called children. When these hierarchies exist, there are many benefits from an organizational standpoint as well as for practical application.

Where there is a series of objects connected together in such a manner, if something on the parent object is changed--such as being moved, rotated, or scaled--all the attached objects do the same in relation to the parent.

Parenting is something that also applies to prefabs. With that in mind, we will parent our objects in the scene together and make a prefab from them; let's perform the following steps:

1. Take a look at our Hierarchy view; we should still have Platform, Hello, and World:
   
   

2. Select Hello and drag it up onto Platform until you see a light blue oval over the destination. Then, release the mouse button:
   
   

3. Now, do the same thing for the World object. After you are done, you should see this in your Hierarchy view; your Hello and World objects are now children of Platform:

If you click on the Play button now to test your app, even after parenting the Hello and World objects, they will fall onto the Platform.

Here's a quick test to see the...