What is Unity?

Unity is a paradox. It is a video game engine that is not a video game engine, or rather, it is so much more than that.

Firstly, what's a video game engine? Aww, come on. Are you really reading this book and asking that? Okay, you are forgiven. Maybe you are recovering from a mind-wipe. A video game engine is a software tool that helps you to create a video game. One example of an incredibly famous video game engine would be… Unity!

Unity was first released in 2005. It was available only on Mac and could only publish games for Mac. That very quickly changed and now, over a decade later, Unity is a mature and capable (though not yet sentient) piece of software. Unity is available for use on Windows, macOS, and Linux. As of this writing, Unity can create 3D and 2D games for more than 25 different platforms! These platforms include Windows, macOS, and Linux as well as WebGL, PlayStation, Xbox, Nintendo Switch, various virtual reality and augmented reality platforms, and more!

Here is an example of a made-in-Unity, first-person-shooter:

Fig. 1.1 – Escape from Tarkov. Developer: Battlestate Games

And here is an example of a retro 2D arcade game:

Fig. 1.2 – Cup Head. Developer: Studio MDHR

When I say Unity can "create games," I don't actually mean it can only "create games." That's just the tip of the planetoid. Unity is currently used to create many different kinds of experiences in areas and industries besides video games, including the fields of virtual/augmented/extended reality (VR/AR/XR), simulation, real-time cinema, film pre-visualization, and automotive design and marketing. Oh yeah, let's not leave out construction, architecture, art installations, engineering, and research data visualization. Got all that? For those of you sitting in the back, there may be a pop quiz later.

Now, it's true that there are other powerful game engines out there, such as Unreal, Godot, and so on. So why should Unity be your go-to game engine of choice?

Top 12 Reasons for Using Unity

These are the top reasons for using Unity as your game engine of choice:

1. Versatility: If you can dream it, you can build it, all the way up to AAA titles. Unity has an amazing toolset that allows you to create 2D and 3D games ranging from the very simple to the very complex. It can be your go-to choice whether you are re-making Pong or creating the next best MMORPG.
2. Ease of Learning: To be clear, Unity development can get very complex. But to get started with Unity and produce something surprisingly fun and advanced can take as little as 15 minutes. And Unity caters to different learning styles, with visual scripting available for those who prefer that to code editing.
3. Portability: With little to no modification, you can get your latest masterpiece running on a number of the many platforms Unity supports, including desktop, web, mobile, and XR!
4. Community: You are not alone. Unity has a development community of over 1.5 million people. You read that right, 1.5 million humans. Of course, that is insignificant on a galactic scale, but from your limited perspective, it is quite impressive. This means that if you run into a problem or need advice, the answers are out there in cyberspace. The Unity developer community is very friendly and encouraging as well. 
5. Learning support: Unity has excellent documentation as well as an extensive, dedicated, free learning site: https://learn.unity.com. This is not to mention the hundreds of high-quality tutorial videos on YouTube as well as the many excellent how-to books available (such as this one!).
6. Customizability: Every developer and every project is different. The Unity editor is tremendously configurable and even programmable. You can create in-editor custom tools to make working on your specific game much easier. And if you need a certain special visual quality for your game? Even the rendering pipeline Unity uses for graphics is programmable and customizable. 
7. Price: Free! Did I mention that already? You only need to start paying a fee if your games start making gobs of money. Gobs.
8. Reach: You have certainly played a Unity-made game before whether you knew it or not. As of the writing of this book, Unity games have reached over 500 million gamers and the Unity engine is responsible for creating 34% of free mobile games on the market. Unity games reach every game market there is.
9. Assets: 3D models, 2D art, visual effects, sound effects, GUIs, tools, templates, and much more. Back in the bad old days of game development, there were some powerful game engines and development technologies available (anyone remember Microsoft's XNA?) but, as an indie developer or hobbyist, there was nothing to put into your game unless you created it yourself or paid (or mind-controlled) a talented artist. It cannot be overstated how valuable the Unity Asset Store is, whether for assets to use in prototyping or in your final release. And some very high-quality assets are available for free. In fact, on our journey, we will use multiple free assets in addition to the ones we create.
10. Development Support Tools: Unity includes tools for integration with different code editors/IDEs, version control systems, asset creation tools (such as Photoshop), and it supports collaborative team development as well.
11. Monetization-Friendliness: Unity wants you to profit from your efforts! Built-in packages such as Unity Ads and In-App Purchases make it easy to build revenue opportunities into your game. And the Unity Analytics tools allow you to discover and make use of insights about how players play your game. Even minor game changes can greatly boost the success of your game.
12. Maturity: Unity has been around long enough that most of its sharp edges have been smoothed. Over and over, every day the engine proves itself to be stable, effective, and reliable.

With Unity explained away, let's take a look at the other focus of this book…