Preface

Unity is a 3D game authoring tool for Mac and PC. Game engines are the nuts and bolts that sit behind the scenes of every video game. From the artwork right down to the mathematics that decide every frame on screen, the "engine" makes the decisions. Starting out with rendering—the method of displaying graphics on screen, and integrating a control method and a set of rules for the game to follow—the engine is what a developer builds to "house" the game. Modern 3D game engines are a deluge of meticulously written code, and as such, once used for their intended purpose (which is the production of a game they are made for), these engines are often sold, modified, and reused. An obvious example of this is the Epic Games Unreal Engine. Originally developed in the late 90s for Unreal—a PC First Person Shooter—the engine has gone on to see massive success in its more recent incarnations, being licensed by other developers for literally hundreds of commercial games and simulations.

Due to the level of complexity and cost of such commercial game engines, the game development industry is a difficult area of interest for potential fresh talent to break into, without studying programming languages such as C++ extensively. Modern console and computer games are built around C++ as it is currently the most efficient language in terms of computational speed, and as such, the structure and commands of commercial games engines require thousands upon thousands of such lines of code to function. This code is delivered in Unity with the help of just-in-time compilation (known as JIT), using the open source C++ library Mono. By using JIT compilation, engines such as Unity can take advantage of high-speed compilation, whereby the code you will write for Unity is compiled to Mono just before it is executed. This is crucial for games that must execute code at specific moments during runtime. In addition to the Mono library, Unity also takes advantage of other software libraries in its functionality, such as Nvidia's PhysX physics engine, OpenGL, and DirectX for 3D rendering and OpenAL for audio. All these libraries are built into the application, so you will not need to worry about learning how to use them individually. So, simply sit back and enjoy them working for you seamlessly within Unity.

The developers of engines also build tools with which to command the functional coding they have created. For example, the creation of an outdoor terrain is held in a set of instructions which define its shape (or topography), visual appearance, and even how it responds to deformation in game. But this set of instructions would be inefficient as a part of the game engine were it not attached to a visual tool to control the aforementioned properties. This is where a Graphical User Interface (GUI) comes in. Game engine developers will often build an interface of tools to aid their team in manipulating parts of the engine in order to save time in the development process and make the engine accessible to potential buyers, post production. This is also true of Unity, as it has a very strong community of users that share their tools in the form of plugins for the package. Visit the Unify community wiki at http://www.unifycommunity.com/wiki for more information.

For many new potential developers, the steep learning curve required to pick up programming languages such as C++, or the engines that utilize it, is simply too great a task to attempt. Without completing degree-level studies in programming or computer animation, it is difficult for many enthusiasts to get started in learning the concepts, methods, and design principles involved in game production. Unity Technologies is one such company that has set out to rectify this. Starting with their own game engine in 2001, the Danish-based game development company endeavoured to strip down their complex game development tools and make a simple, user-driven package that anyone could pick up and begin experimenting with. The team resolved to keep the source code that drives the engine behind the scenes, instead providing a complete GUI (Graphical User Interface) that allows the user to control the powerful engine source code without ever having to create parts of it themselves. This factor has made Unity highly popular with new developers, and is likely one of the key reasons you're reading this book. By establishing logical concepts and categorizing common methods involved in game production, Unity puts the power of its engine into the user's hands, allowing maximum results with minimal effort, thereby encouraging experimentation with the most crucial factor of all—gameplay.

Having appealed to many games developers, Unity has filled a gap in the games development market that few others can fully claim to cater to. Having the ability to produce professional standard games, publish 3D to both Mac and PC, as well as having its own Web Player, Unity is one of the fastest growing game engines in its sector. The engine also has its own Nintendo Wii and Apple iPhone developing versions, meaning that once you have mastered the basics, a pipeline to not only home computer, but also to console and mobile development lies ahead of you.

The fast pace of the entertainment and marketing industries requires a quick turnaround of gaming media. Also, many companies are now looking to packages such as Unity to enable their creatives to produce better products with the greatest of ease. With 2009 seeing the release of Unity version 2.5, and its first steps onto PC format, its usage looks set to skyrocket. But what is Unity? How does it work? What can it do? And most importantly, how can it get you get started on the path to 3D game development in just a few weeks?