To make sure that everything works fine, we will first see if we can deploy the app to the HoloLens emulator. If you have decided not to install this and choose to use a physical device instead, please skip to the next part.

In the menu bar, you can choose the environment you want to run the app on. You might be familiar with this, but if you are not, this is where you specify where the app will be deployed. You have several options, such as the local machine and a remote machine. Those two are the most used in normal development, such as if you are writing a universal Windows platform application or a website, but that will not work for us. We need to deploy the app to a Holographic capable device such as the emulator. If you have installed that, it will show up here in the menu, as follows:

The deployment options

The version of the emulator might be different on your system--Microsoft continuously updates its software, so you might have a newer version. The one shown here is the latest one that was available during the writing of this book.

Now that you have selected this, you can select Run (through the green arrow, pressing F5, or through the Debug | Start Debugging menu). If you do that the emulator will start up. This might take some time. After all, it is starting up a new machine in the Hyper-V environment, loading Windows 10, and deploying your app.

However, after a couple of minutes, you will be greeted with the following view:

Our first HoloLens app in the emulator!

You will see a rotating multicolored cube on a black background.

Before we can dive into the code, it would be worthwhile to learn to use the emulator a bit. Obviously, you cannot use the gestures we have talked about before--it will not see what you are doing and you have to emulate these. Fortunately, it is not too hard to get used to the controls. You can use the mouse or the keyboard, or you can attach an Xbox controller to your machine and use that as well. We will cover the main controls; the more advanced options will be discussed when we need them in later chapters.

The following table shows the Keyboard, mouse, and Xbox controls in the emulator:

In the center of your view, you will see a dot; this is the cursor. Do not try to move this dot--this will always be in that spot. Move the emulator with the walk and look options to position the dot on the menu item you want to choose, then perform the air tap with the options mentioned above. This takes some practice, so try it out for a little while; it will be worth the effort.

Using the emulator can be a great tool in your toolbox, especially when you are working in a team; having a device for each developer is usually not an option. The devices are pretty expensive, and you don't need one to develop your app. Of course, when you are working on a project, it is invaluable to deploy to the device every now and then and see how your code behaves in the real world. After all, you can only experience the true power of the HoloLens by putting it on.

So, we need to deploy the code to the device. First of all, you need to make sure that you have the Developer Mode switched on. You can do this by going to the Settings app and selecting the For Developers option in the Update part. There, you can switch the Developer mode on.

Once you have done this, you can start the deployment from Visual Studio to the device. To do this, you have two options:

Since you already have set up the device to use the network, you can use the option. This one tends to be slightly slower than using the USB deployment, but it has the advantage that you can do this without having a wire attached to the device. Trust me--this has some advantages. I have done a deployment through USB only to discover I could not immediately stand up and walk around my holograms--I forgot the cable was still attached to the device.

Deploying through Wi-Fi

If you chose the Wi-Fi deployment option, you can choose Remote as your deployment target. If you do this the first time, you will get a menu where you can pick the device out of a list of available devices. The autodiscovery method does not always work--every now and then, you need to enter the IP address manually.

You can find this IP address in the Settings | Network & Internet | Advanced Options menu on the device. This is the same IP address you use to launch the device portal.

The Remote Connections dialog

Make sure that you have the Authentication Mode set to Universal, otherwise your device will not accept the connection.

You need to take an additional step to deploy--your device needs to pair with your computer. This way you can be sure that no other people connect to it without you knowing it. If you start the debugger using the Remote Machine option or try to deploy to the Remote Machine, you will get a dialog box asking you for a PIN.

Visual Studio asking for the PIN to pair

This pin can be obtained in the device by navigating to the Settings app, then to Update, and then selecting For Developers. Here, you can pair the device. If you select this, you will get a PIN globally for each machine you want to connect. Enter this pin in the dialog and you are all set to go--the device should receive your app now. If you choose Deploy in Visual Studio, the app will show up in your list on the device. You can find it by starting the Start screen with the Bloom gesture, then select the + on the right-hand side of the menu. There, you will find the list with all the installed apps, including your new HelloHoloWorld project. Air-tap this to start it. If you are done with it, you can do the Bloom again to go back to the main menu.

Note

If you happen to forget the pin, do not worry. All you have to do is enter a wrong number three times in a row. After that, the device will ask you to reconnect once again from scratch, enabling you to think of a new pin.

If you choose Debug, the app will start automatically--you do not have to select it in the device.

The code you just wrote is a C#, UWP Windows 10 app using DirectX through the SharpDX library. In later chapters, we will examine this much more closely. DirectX is the technology that allows us to write fast-running apps that use a lot of graphics, such as the holograms we create. However, DirectX is a C++ library and can officially only be used in C++ programs. Luckily, the people at SharpDX have written a wrapper around this, so we can use this in our C# applications and apps as well, this is the reason why the HoloLens SDK developers included this in the template. For more information about SharpDX, I suggest that you have a look at their site at http://sharpdx.org/.

The app uses some libraries from the Windows SDK. However, if you look closely at the References part in the solution, you will note that there are no Holographic-specific libraries included. The reason for this is that the APIs needed to run Holographic apps are standard in the Windows 10 runtime. That is right; your Windows 10 computer has all the code it needs to run Holographic apps. Unfortunately, the hardware you have will not support these APIs, so they are not available to use. If you try to deploy this app to a normal machine, you will get errors--the required capabilities are not available and the runtime will refuse to install the app.

This means that our app is a standard Windows 10 UWP app with some extra capabilities added. If you right-click on the Package.appxmanifest, you will find the following tag somewhere:

 <Dependencies> 
    <TargetDeviceFamily Name="Windows.Holographic" MinVersion="10.0.10240.0" MaxVersionTested="10.0.10586.0" /> 
  </Dependencies> 

This is what makes sure that our device accepts our app and other systems do not--the app is marked for usage in Windows. holographic-capable device. The numbers you see in MinVersion and MaxVersionTested may differ--these depend on the SDK versions that you have installed and chose when you created the project.

The structure of the project

If you have written UWP apps before, you will see that the structure of this app is quite different. This is mostly because of the code SharpDX needs to start up. After all, a Holographic app needs a different kind of user interface than a normal screen-based app. There is no notion of a screen, no place to put controls, labels, or textboxes, and no real canvas. Everything we do needs to be done in a 3D world. An exception to this is when we create 2D apps that we want to deploy to the 3D environment. Examples of this are the Edge Browser and the now familiar Settings app. Those are standard UWP apps running on HoloLens. We will see how to build this later on.

The project should look like this:

The project structure

As you can see, we have the normal Properties and References parts. Next, we have the expected Program.cs and Assets folder. That folder contains our logos, start screen, and other assets we usually see with UWP apps. Program.cs is the starting point of the app. We also can identify the HelloHoloWorld_TemporaryKey.pfx. The app needs to be signed in order to run on the device, and this is the key that does this. You cannot use this key to deploy to the store, but since we have set our device in developer mode, it will accept our app with a test key such as this one. Package.appxmanifest we have already looked at.

The other files and folder might not be that familiar.

The Common folder contains a set of helper classes that help us use SharpDX. It has some camera helpers that act as viewport to the 3D world, timers that help us with the animation of the spinning cube, and so on.

The Content folder has the code needed to draw our spinning cube. This has the shaders and renderers that SharpDX needs to draw the cube we see when we start the app. We will have a closer look at how this works in later chapters.