Unity 4.x Game Development by Example: Beginner's Guide: A seat-of-your-pants manual for building fun, groovy little games quickly with Unity 4.x , Third Edition

The idea's the thing. Every game starts with an idea—that little lightbulb above your head that flicks on all of a sudden and makes you say, "Aha!" If you've gone as far as picking up a book on Unity, you probably have at least one game idea floating around in your noggin. If you're like me, you really have 10,000 game ideas floating around in your head, all clamoring for your attention. "Build me! Build me!" Which of these ideas should you go ahead with?

The quality that defines a successful game developer is not the number of ideas he has. The guy with 10 game ideas is equally as valuable as the girl with 500 game ideas. They're both essentially worthless! A game developer develops games. The one thing that separates you from success is not the number of ideas you've had or the number of projects you've started and abandoned. It's the games you've finished that count. To put it another way: he who executes, wins. Don't worry about getting it right just yet; worry about...

The biggest barrier between you and your success as a Unity game developer is finishing a project. The idea stage that you enter when you sit staring at that endless 3D plane is crucial to you overcoming that barrier. If you choose the right idea, you will have a much better shot at finishing. Choose the wrong idea, and you might crash and burn. Then you'll probably go back to school and study to be an accountant. Starting in game development and ending in accounting is your worst-case scenario. Let's avoid that at all costs.

Before you even begin, the odds are stacked against you. That endless 3D plane is calling you, begging you to start a project that's way over your head. You may begin thinking of the other 3D games you've played: gritty, wide-open "sandbox" games like Saints Row or Grand Theft Auto; tightly-controlled platformer games with lots of exploration and interesting challenges like Super Mario 64; sweeping, epic role-playing games like Skyrim or Fallout...

Another trap fledgling game developers fall into is reducing the scope of their ideas in ways that still prove the project impossible. For example, they'll say, "I don't want to set my sights too high, so I'm going to make a game such as Gran Turismo, except with fewer cars," or "I want to make Diablo III with smaller levels," or "I'm going to build World of Warcraft with fewer classes and about half the items".

To understand why this approach is so dangerous we'll have to understand a little more about how games are put together. The two issues here are features and content. All things being equal, a game with 50 levels has more content than a game with 5 levels. The 50-level game has ten times more content, but both games have the same feature: levels. A role-playing game with twelve character classes has more content than a game with three character classes, but they both have the same feature: character classes.

So, while you may recognize that it's more work to...

We see how it can be dangerous and self-defeating to choose a game with many features and reduce the amount of content in that game. And, because some features are so time-consuming to develop, it's also dangerous to choose a fully featured game and start stripping features to reduce the scope of our project.

A much better approach, and one that you'll have much more success with, is to start with a game that has zero features, and then add them slowly, one by one. Using this approach, you can decide when your game is good enough to unleash on your players, and any additional features you had planned can go into the sequel. This is a winning approach that will see you through many small victories, and many finished games!

One skill that may help you finish a game is recognizing the difference between mechanic and skin. Your game's mechanic is how it physically functions. The very best games contain a simple mechanic that's easy to learn, hard to master, and compelling enough to keep a player interested. The mechanic in Tetris is to move and rotate falling blocks into place to create and eliminate one or more solid lines. The mechanic in many golf games is to simulate swinging a golf club by moving the controller's thumbstick around or tapping a button when the "Power" and "Accuracy" meters are at the right level. The mechanic in Breakout is to move a paddle back and forth to bounce a ball into a wall of fragile bricks.

A game's skin is how it looks and sounds. It's the animated cutscenes that establish a story. It's the theme that you choose for your game. Imagine a game where you've programmed an object to follow the mouse cursor. There are "bad" objects on the screen that you must avoid...

The advantage that you gain by separating a mechanic from a skin is that you can shuck off video game conventions and free yourself to develop anything you want. If you think, "I'd like to create a space-themed strategy game," and you think back to all of the space-themed strategy games that you've played, you might think of 4X games like Alpha Centauri or Master of Orion—they both pit you in a massive quest to conquer the universe. They are huge games that you likely won't finish alone. So, you start trimming them down for sanity's sake—"I'll just build Master of Orion with fewer planets," or "I'll just build Alpha Centauri with fewer features". Now you've unwittingly fallen into that self-defeating trap. Your project is still too huge. You eventually abandon all hope. A few years later, you're an accountant wondering what might have been.

Instead of going down that doomed copycat road, start asking yourself questions about the outer space theme and the strategy mechanic. What's fun about each of them? Which moments in a game like Master of Orion really turn your crank? Do you like mining a planet for resources and buying new stuff? Do you like the thrill of discovering a new planet? Or does building an armada of spaceships and conquering enemies really get you excited?

Distill your game down to that one thing—that singular piece of joy. Create that one joyful experience for your player, and nail it. That's your game. Everything else is just feature creep.

The Internet is packed with small, simple, and free-to-play games that offer the cheap thrill of a singular piece of joy. Let's analyze some of these games to see what we can learn. For each example, we'll identify:

These games require the Flash Player plugin, which you probably already have. If, for some weird reason, your computer's been living under a digital rock and you need to install it, browse to http://get.adobe.com/flashplayer/ and follow the instructions there.

Motherload by XGen Studios (http://www.xgenstudios.com/play/motherload) distills a complicated 4X game, like Master of Orion, down to two joy-inducing tasks: mining for resources and shopping for stuff. Here's a screenshot from the game:

The core mechanic: Pilot your vehicle by using the arrow keys—dig, fly, and avoid long falls—with a finite fuel source. There's only one real "level" in the game, and it stretches down your screen for a long time. Your drill-enabled vehicle can only dig down so deep and dig up so many pieces of ore before having to return to the surface to sell off the goods and clear some cargo space. The trick is to dig up and sell enough ore to upgrade your ship so that it can dig deeper, carry more loot, and survive longer falls. The initial goal is to rack up ludicrous cash, but a story eventually develops that adds meaning to your loot-lust. This mechanic is similar to the much simpler game Lunar Lander, where the player must gently land a spacecraft on...

Pay close attention to a game's Head-up display (HUD). Video game HUDs contain graphical elements that usually don't make sense within the context of the game world, but they provide vital information to the player. A great example is the heart health meter in any Zelda game, or the energy bar in any fighting game. The Motherload HUD includes draining Fuel and Hull bars. It displays dynamic money and depth tallies. Three clickable elements lead the player to the Inventory, Options, and Instructions screens. Finally, a piece of text lets the player know that there are more shops to be found past the borders of the viewable game area.

Unity has great features for building game HUDs. Every HUD item type that you see in Motherload—the graphical bar, the dynamic (changeable) text, the clickable icons, and the flashing helper text—can all be built in the Unity game engine. Skip ahead to Chapter 4, Code Comfort if you're dying to try it!

Artillery Live! (http://www.gamebrew.com/game/artillery-live/play) is one of the many, many iterations of the classic Artillery game mechanic, which is nearly as old as video games themselves. It was also built in Flash, but there's no reason it couldn't be built in Unity using 3D tank models and some awesome exploding particle effects.

The core mechanic: Artillery games share a familiar mechanic where the player sets the trajectory and power of his shot to demolish the enemy tanks. This version also has a wind speed feature that affects the way the tank shells travel through the air. Over time and in other incarnations, the game mechanic evolved into a pull-back-and-release experience, mimicking a slingshot. Other versions have the gun turret automatically angling towards the mouse, and the player holds down the mouse button to power up his shot.

The skin: The Gamebrew version is a classic tanks-and-mountains affair, holding true to the very first Artillery games developed...

Seriously, Pong? Yes, Pong. The British Academy of Film and Television Arts hosts an online version of the classic game (http://www.bafta.org/games/awards/play-pong-online,678,BA.html). The original Pong is credited with kick-starting the commercial video game industry that we know today:

The mechanic: Pong takes its name from "ping pong"—a real-world activity where two players use paddles to bounce a ball at each other across a table with a tiny net. Ping pong was adapted from tennis, after people finally realized that all that running around was too much effort.

Some real-world activities lend themselves very well to video game mechanics. Not quite 50-years old, the video game industry is still very much in its infancy. There is an enormous wealth of fun stuff in the physical world (such as playing ping pong or blowing up tanks) that's waiting to be adapted to a terrific video game mechanic. Are you clever enough to find one of those undiscovered mechanics and build the next Pong?

...

The Pong game mechanic is so simple and so effective that its impact can be felt far and wide throughout the annals of video game history.

From Pong, we get Breakout. The innovation here is to turn Pong into a single-player game like real-world handball or squash, with the addition of a breakable brick wall. Breakout introduces stages or levels to the Pong concept, each with a different configuration of bricks:

Arkanoid iterates on Breakout by changing the skin to a sci-fi theme. The paddle becomes a spaceship. Arkanoid adds a few new features, most importantly power-ups that come in the form of capsules that are released when the ball smashes into the bricks. When the player catches the capsules with the spaceship, the game rules get bent. The spaceship can become longer. It can become sticky so that the player can catch the ball and plan the next shot. My favorite Arkanoid power-up is the red capsule marked L; it enables the spaceship to fire...

The approach that we're taking to your initial idea phase is not an approach that comes naturally. Usually, new game developers want to start with setting the story and characters, as if writing a book. That's how we've always been taught to begin a creative project. As there's often so much overlap between narrative forms such as books, movies, and teevee shows, it's tempting to start there. "My game is about a dark, brooding superwarrior named Kane Glorg who doesn't know who his parents are, so he travels the wasted landscape with his two-handed axe and his vicious battle sloth, slicing through hordes of evil slime demons in his ultimate quest to punch Satan in the face."

The take-away from this chapter is that all that stuff is window dressing. When you're just starting out (and unless you're building an explicitly narrative game like a graphic or text-based adventure), story, setting, and character are the end point, not the start point. Too many would-be game developers...

The sky's the limit, and Unity starts us off with an endless sky. But through this chapter, we've seen that that endless sky can actually trap us into an ambitious concept that we'll have no chance of completing. So, let's redefine the sky. Instead of wondering how big and complex your game can be, think about the endless array of simple interactions and moments of joy our world contains. Throwing and catching a ball, knocking a pile of stuff over, feeding an animal, growing a plant—the world is packed with simple, effective interactions that ignite our most primitive, most basic "Joy Cortices", which is a neurological term that I've entirely invented just now.

If you want to discover one of these joy-producing real-world moments, study a child. Because games are all about playing, the simple things that amuse and delight children and babies are the stuff of award-winning games. What is Metal Gear Solid if not a complex game of hide and seek? Rock Band and Guitar Hero are...

In case you ever need to answer a multiple-choice quiz on this chapter, here's a quick rundown of what we've learned: