This virtual reality thing calls into question, what does it mean to "be somewhere"?

Before cell phones, you would call someone and it would make no sense to say, "Hey, where are you?" You know where they are, you called their house, that's where they are.

So then cell phones come around and you start to hear people say, "Hello. Oh, I'm at Starbucks," because the person on the other end wouldn't necessarily know where you are, because you became un-tethered from your house for voice communications.

So when I saw a VR demo, I had this vision of coming home and my wife has got the kids settled down, she has a couple minutes to herself, and she's on the couch wearing goggles on her face. I come over and tap her on the shoulder, and I'm like, "Hey, where are you?"

It's super weird. The person's sitting right in front of you, but you don't know where they are.

-Jonathan Stark, mobile expert and podcaster

In this article, by Jonathan Linowes, author of the book Unity Virtual Reality Projects, we will define virtual reality and illustrate how it can be applied not only to games but also many other areas of interest and productivity.

Welcome to virtual reality! In this book, we will explore what it takes to create virtual reality experiences on our own. We will take a walk through a series of hands-on projects, step-by-step tutorials, and in-depth discussions using the Unity 5 3D game engine and other free or open source software. Though the virtual reality technology is rapidly advancing, we'll try to capture the basic principles and techniques that you can use to make your VR games and applications feel immersive and comfortable.

This article discusses the following topics:

What is virtual reality?
Differences between virtual reality (VR) and augmented reality (AR)
How VR applications may differ from VR games
Types of VR experiences
Technical skills that are necessary for the development of VR

What is virtual reality to you?

Today, we are witnesses to the burgeoning consumer virtual reality, an exciting technology that promises to transform in a fundamental way how we interact with information, our friends, and the world at large.

What is virtual reality? In general, VR is the computer-generated simulation of a 3D environment, which seems very real to the person experiencing it, using special electronic equipment. The objective is to achieve a strong sense of being present in the virtual environment.

Today's consumer tech VR involves wearing a head-mounted display (such as goggles) to view stereoscopic 3D scenes. You can look around by moving your head, and walk around by using hand controls or motion sensors. You are engaged in a fully immersive experience. It's as if you're really there in some other virtual world. The following image shows a guy experiencing an Oculus Rift Development Kit 2 (DK2):

Virtual reality is not new. It's been here for decades, albeit hidden away in academic research labs and high-end industrial and military facilities. It was big, clunky, and expensive. Ivan Sutherland invented the first head-mounted display in 1966, which is shown in the following image. It was tethered to the ceiling! In the past, several failed attempts have been made to bring consumer-level virtual reality products to the market.

virtually-everything-everyone-img-1

In 2012, Palmer Luckey, the founder of Oculus VR LLC, gave a demonstration of a makeshift head-mounted VR display to John Carmack, the famed developer of Doom, Wolfenstein 3D, and Quake classic video games. Together, they ran a successful Kickstarter campaign and released a developer kit called Oculus Rift Development Kit 1 (DK1) to an enthusiastic community. This caught the attention of investors as well as Mark Zuckerberg, and in March 2014, Facebook bought the company for $2 billion. With no product, no customers, and an infinite promise, the money and attention that it attracted has helped fuel a new category of consumer products. Others have followed suit, including Google, Sony, Samsung, and Steam. New innovations and devices that enhance the VR experience continue to be introduced.

Most of the basic research has already been done and the technology is now affordable thanks in large part to the mass adoption of devices that work on mobile technology. There is a huge community of developers with an experience in building 3D games and mobile apps. Creative content producers are joining in and the media is talking it up. At last, virtual reality is real!

Say what? Virtual reality is real? Ha! If it's virtual, how can it be... Oh, never mind.

Eventually, we will get past the focus on the emerging hardware devices and recognize that content is king. The current generation of 3D development software (commercial, free, and open source) that has spawned a plethora of indie, or independent, game developers can also be used to build non-game VR applications.

Though VR finds most of its enthusiasts in the gaming community, the potential applications reach well beyond that. Any business that presently uses 3D modeling and computer graphics will be more effective if it uses the VR technology. The sense of immersive presence that is afforded by VR can enhance all common online experiences today, which includes engineering, social networking, shopping, marketing, entertainment, and business development. In the near future, viewing 3D websites with a VR headset may be as common as visiting ordinary flat websites today.

Types of head-mounted displays

Presently, there are two basic categories of head-mounted displays for virtual reality—desktop VR and mobile VR.

Desktop VR

With desktop VR (and console VR), your headset is a peripheral to a more powerful computer that processes the heavy graphics. The computer may be a Windows PC, Mac, Linux, or a game console. Most likely, the headset is connected to the computer with wires. The game runs on the remote machine and the head-mounted display (HMD) is a peripheral display device with a motion sensing input. The term desktop is an unfortunate misnomer since it's just as likely to be stationed in either a living room or a den.

The Oculus Rift (https://www.oculus.com/) is an example of a device where the goggles have an integrated display and sensors. The games run on a separate PC. Other desktop headsets include HTC/Valve Vive and Sony's project Morpheus for PlayStation.

The Oculus Rift is tethered to a desktop computer via video and USB cables, and generally, the more graphics processing unit (GPU) power, the better. However, for the purpose of this book, we won't have any heavy rendering in our projects, and you can get by even with a laptop (provided it has two USB ports and one HDMI port available).

Mobile VR

Mobile VR, exemplified by Google Cardboard (http://www.google.com/get/cardboard/), is a simple housing (device) for two lenses and a slot for your mobile phone. The phone's display is used to show the twin stereographic views. It has rotational head tracking, but it has no positional tracking. Cardboard also provides the user with the ability to click or tap its side to make selections in a game. The complexity of the imagery is limited because it uses your phone's processor for rendering the views on the phone display screen. Other mobile VR headsets include Samsung Gear VR and Zeiss VR One, among others.

Google provides the open source specifications, and other manufacturers have developed ready-made models for purchase, with prices for the same as low as $15. If you want to find one, just Google it! There are versions of Cardboard-compatible headsets that are available for all sizes of phones—both Android and iOS.

Although the quality of the VR experience with a Cardboard device is limited (some even say that it is inadequate) and it's probably a "starter" device that will just be quaint in a couple of years, Cardboard is fine for the small projects in this book, and we'll revisit its limitations from time to time.

The difference between virtual reality and augmented reality

It's probably worthwhile clarifying what virtual reality is not.

A sister technology to VR is augmented reality (AR), which superimposes computer generated imagery (CGI) over views of the real world. Limited uses of AR can be found on smart phones, tablets, handheld gaming systems such as the Nintendo 3DS, and even in some science museum exhibits, which overlay the CGI on top of live video from a camera.

The latest innovations in AR are the AR headsets, such as Microsoft HoloLens and Magic Leap, which show the computer graphics directly in your field of view; the graphics are not mixed into a video image. If the VR headsets are like closed goggles, the AR headsets are like translucent sunglasses that employ a technology called light fields to combine the real-world light rays with CGI. A challenge for AR is ensuring that the CGI is consistently aligned with and mapped onto the objects in the real-world space and eliminate latency while moving about so that they (the CGI and objects in real-world space) stay aligned.

AR holds as much promise as VR for future applications, but it's different. Though AR intends to engage the user within their current surroundings, virtual reality is fully immersive. In AR, you may open your hand and see a log cabin resting in your palm, but in VR, you're transported directly inside the log cabin and you can walk around inside it.

We can also expect to see hybrid devices that somehow either combine VR and AR, or let you switch between modes.

Applications versus games

The consumer-level virtual reality starts with gaming. Video gamers are already accustomed to being engaged in highly interactive hyper-realistic 3D environments. VR just ups the ante.

Gamers are early adopters of high-end graphics technology. Mass production of gaming consoles and PC-based components in the tens of millions and competition between vendors leads to lower prices and higher performance. Game developers follow suit, often pushing the state-of-the-art, squeezing every ounce of performance out of hardware and software. Gamers are a very demanding bunch, and the market has consistently stepped up to keep them satisfied. It's no surprise that many, if not most, of the current wave of the VR hardware and software companies are first targeting the video gaming industry. A majority of the demos and downloads that are available on Oculus Share (https://share.oculus.com/) and Google Play for the Cardboard app (https://play.google.com/store/search?q=cardboard&c=apps) are games. Gamers are the most enthusiastic VR advocates and seriously appreciate its potential.

Game developers know that the core of a game is the game mechanics, or the rules, which are largely independent of the skin, or the thematic topic of the game. Gameplay mechanics can include puzzles, chance, strategy, timing, or muscle memory (twitch). VR games can have the same mechanic elements but might need to be adjusted for the virtual environment. For example, a first-person character walking in a console video game is probably going about 1.5 times faster than their actual pace in real life. If this wasn't the case, the player would feel that the game is too slow and boring. Put the same character in a VR scene and they will feel that it is too fast; it could likely make the player feel nauseous. In VR, you will want your characters to walk a normal, earthly pace. Not all video games will map well to VR; it may not be fun to be in the middle of a war zone when you're actually there.

That said, virtual reality is also being applied in areas other than gaming. Though games will remain important, non-gaming apps will eventually overshadow them. These applications may differ from games in a number of ways, with the most significant having much less emphasis on game mechanics and more emphasis on either the experience itself or application-specific goals. Of course, this doesn't preclude some game mechanics. For example, the application may be specifically designed to train the user at a specific skill. Sometimes, the gamification of a business or personal application makes it more fun and effective in driving the desired behavior through competition.

In general, non-gaming VR applications are less about winning and more about the experience itself.

Here are a few examples of the kinds of non-gaming applications that people are working on:

Travel and tourism: Visit faraway places without leaving your home. Visit art museums in Paris, New York, and Tokyo in one afternoon. Take a walk on Mars. You can even enjoy Holi, the spring festival of colors, in India while sitting in your wintery cabin in Vermont.
Mechanical engineering and industrial design: Computer-aided design software such as AutoCAD and SOLIDWORKS pioneered three-dimensional modeling, simulation, and visualization. With VR, engineers and designers can directly experience the hands-on end product before it's actually built and play with what-if scenarios at a very low cost. Consider iterating a new automobile design. How does it look? How does it perform? How does it appear sitting in the driver's seat?
Architecture and civil engineering: Architects and engineers have always constructed scale models of their designs, if only to pitch the ideas to clients and investors, or more importantly, to validate the many assumptions about the design. Presently, modeling and rendering software is commonly used to build virtual models from architectural plans. With VR, the conversation with stakeholders can be so much more confident. Other personnel, such as the interior designers, HVAC, and electrical engineers, can be brought into the process sooner.
Real estate: Real estate agents have been quick adopters of the Internet and visualization technology to attract buyers and close sales. Real estate search websites were some of the first successful uses of the Web. Online panoramic video walk-throughs of for-sale properties are commonplace today. With VR, I can be in New York and find a place to live in Los Angeles. This will become even easier with mobile 3D-sensing technologies such as Google Project Tango (https://www.google.com/atap/projecttango), which performs a 3D scan of a room using a smartphone and automatically builds a model of the space.
Medicine: The potential of VR for health and medicine may literally be a matter of life and death. Every day, hospitals use MRI and other scanning devices to produce models of our bones and organs that are used for medical diagnosis and possibly pre-operative planning. Using VR to enhance visualization and measurement will provide a more intuitive analysis. Virtual reality is also being used for the simulation of surgery to train medical students.
Mental health: Virtual reality experiences have been shown to be effective in a therapeutic context for the treatment of post traumatic stress disorder (PTSD) in what's called exposure therapy, where the patient, guided by a trained therapist, confronts their traumatic memories through the retelling of the experience. Similarly, VR is being used to treat arachnophobia (spiders) and the fear of flying.
Education: The educational opportunities for VR are almost too obvious to mention. One of the first successful VR experiences is Titans of Space, which lets you explore the solar system first hand. Science, history, arts, and mathematics—VR will help students of all ages because, as they say, field trips are much more effective than textbooks.
Training: Toyota has demonstrated a VR simulation of drivers' education to teach teenagers about the risks of distracted driving. In another project, vocational students got to experience the operating of cranes and other heavy construction equipment. Training for first responders, police, and the fire and rescue workers can be enhanced with VR by presenting highly risky situations and alternative virtual scenarios. The NFL is looking to VR for athletic training.
Entertainment and journalism: Virtually attend rock concerts and sporting events. Watch music videos Erotica. Re-experience news events as if you were personally present. Enjoy 360-degree cinematic experiences. The art of storytelling will be transformed by virtual reality.

Wow, that's quite a list! This is just the low-hanging fruit.

The purpose of this book is not to dive too deeply into any of these applications. Rather, I hope that this survey helps stimulate your thinking and provides a perspective towards how virtual reality has the potential to be virtually anything for everyone.

What this book covers

This book takes a practical, project-based approach to teach the specifics of virtual reality development using the Unity 3D game development engine. You'll learn how to use Unity 5 to develop VR applications, which can be experienced with devices such as the Oculus Rift or Google Cardboard.

However, we have a slight problem here—the technology is advancing very rapidly. Of course, this is a good problem to have. Actually, it's an awesome problem to have, unless you're a developer in the middle of a project or an author of a book on this technology! How does one write a book that does not have obsolete content the day it's published?

Throughout the book, I have tried to distill some universal principles that should outlive any near-term advances in virtual reality technology, that includes the following:

Categorization of different types of VR experiences with example projects
Important technical ideas and skills, especially the ones relevant to the building of VR applications
General explanations on how VR devices and software works
Strategies to ensure user comfort and avoid VR motion sickness
Instructions on using the Unity game engine to build VR experiences

Once VR becomes mainstream, many of these lessons will perhaps be obvious rather than obsolete, just like the explanations from the 1980's on how to use a mouse would just be silly today.

Who are you?

If you are interested in virtual reality, want to learn how it works, or want to create VR experiences yourself, this book is for you. We will walk you through a series of hands-on projects, step-by-step tutorials, and in-depth discussions using the Unity 3D game engine.

Whether you're a non-programmer who is unfamiliar with 3D computer graphics, or a person with experience in both but new to virtual reality, you will benefit from this book. It is not a cold start with Unity, but you do not need to be an expert either. Still, if you're new to Unity, you can pick up this book as long as you realize that you'll need to adapt to the pace of the book.

Game developers may already be familiar with the concepts in the book, which are reapplied to the VR projects while learning many other ideas that are specific to VR. Engineers and 3D designers may understand many of the 3D concepts, but they may wish to learn to use the game engine for VR. Application developers may appreciate the potential non-gaming uses of VR and want to learn the tools that can make this happen.

Whoever you are, we're going to turn you into a 3D Software VR Ninja. Well, OK, this may be a stretch goal for this little book, but we'll try to set you on the way.

Types of VR experiences

There is not just one kind of virtual reality experience. In fact, there are many. Consider the following types of virtual reality experiences:

Diorama: In the simplest case, we build a 3D scene. You're observing from a third-person perspective. Your eye is the camera. Actually, each eye is a separate camera that gives you a stereographic view. You can look around.
First-person experience: This time, you're immersed in the scene as a freely moving avatar. Using an input controller (keyboard, game controller, or some other technique), you can walk around and explore the virtual scene.
Interactive virtual environment: This is like the first-person experience, but it has an additional feature—while you are in the scene, you can interact with the objects in it. Physics is at play. Objects may respond to you. You may be given specific goals to achieve and challenges with the game mechanics. You might even earn points and keep score.
Riding on rails: In this kind of experience, you're seated and being transported through the environment (or, the environment changes around you). For example, you can ride a roller coaster via this virtual reality experience. However, it may not necessarily be an extreme thrill ride. It can be a simple real estate walk-through or even a slow, easy, and meditative experience.
360-degree media: Think panoramic images taken with GoPro® on steroids that are projected on the inside of a sphere. You're positioned at the center of the sphere and can look all around. Some purists don't consider this "real" virtual reality, because you're seeing a projection and not a model rendering. However, it can provide an effective sense of presence.
Social VR: When multiple players enter the same VR space and can see and speak with each other's avatars, it becomes a remarkable social experience.

In this book, we will implement a number of projects that demonstrate how to build each of these types of VR experience. For brevity, we'll need to keep it pure and simple, with suggestions for areas for further investigation.

Technical skills that are important to VR

You will learn about the following in this book:

World scale: When building for a VR experience, attention to the 3D space and scale is important. One unit in Unity is usually equal to one meter in the virtual world.
First-person controls: There are various techniques that can be used to control the movement of your avatar (first-person camera), such as the keyboard keys, game controllers, and head movements.
User interfacecontrols: Unlike conventional video (and mobile) games, all user interface components are in world coordinates in VR, not screen coordinates. We'll explore ways to present notices, buttons, selectors, and other User interface (UI) controls to the users so that they can interact and make selections.
Physics and gravity: Critical to the sense of presence and immersion in VR is the physics and gravity of the world. We'll use the Unity physics engine to our advantage.
Animations: Moving objects within the scene is called "animation" (duh!) It can either be along predefined paths, or it may use AI (artificial intelligence) scripting that follows a logical algorithm in response to events in the environment.
Multiuser services: Real-time networking and multiuser games are not easy to implement, but online services make it easy without you having to be a computer engineer.
Build and run: Different HMDs use different developer kits (SDK) and assets to build applications that target a specific devise. We'll consider techniques that let you use a single interface for multiple devices.

We will write scripts in the C# language and use features of Unity as and when they are needed to get things done.

However, there are technical areas that we will not cover, such as realistic rendering, shaders, materials, and lighting. We will not go into modeling techniques, terrains, or humanoid animations. Effective use of advanced input devices and hand and body tracking is proving to be critical to VR, but we won't have a chance to get into it here either. We also won't discuss game mechanics, dynamics, and strategies. We will talk about rendering performance optimization, but not in depth. All of these are very important topics that may be necessary for you to learn (or for someone in your team), in addition to this book, to build complete, successful, and immersive VR applications.

Summary

In this article, we looked at virtual reality and realized that it can mean a lot of things to different people and can have different applications. There's no single definition, and it's a moving target. We are not alone, as everyone's still trying to figure it out. The fact is that virtual reality is a new medium that will take years, if not decades, to reach its potential.

VR is not just for games; it can be a game changer for many different applications. We identified over a dozen. There are different kinds of VR experiences, which we'll explore in the projects in this book.

VR headsets can be divided into those that require a separate processing unit (such as a desktop PC or a console) that runs with a powerful GPU and the ones that use your mobile phone for processing. In this book, we will use an Oculus Rift DK2 as an example of desktop VR and Google Cardboard as the example of mobile VR, although there are many alternative and new devices available.

We're all pioneers living at an exciting time. Because you're reading this book, you're one, too. Whatever happens next is literally up to you. As the personal computing pioneer Alan Kay said, "The best way to predict the future is to invent it."

So, let's get to it!