So you want to write a game?

By Alex Hoffer What exactly do you need to know to write a game? Well you, have to know what makes a game fun, of course, but from a technical perspective, what is there to it?
The best way to learn how to write games is, alas, to get a solid grounding in the basics of computer science.
GraphicsThere is perhaps no single area of gaming in which players standards have risen more than in the field of graphics. While players in the 70s and 80s were accustomed to screens of text or 16-bit black-and-white graphics, the users of today demand Riven-quality, 3D graphics, complete with lighting effects, textures, and scale. Unfortunately, graphics are hard to do. They require math, at least on the level of multivariable calculus, and a great deal of time. But if you aren't quite a math wizard yet, don't despair; for more casual games, most people are willing to accept simple 2D sprites. Anyone who's ever been addicted to Tetris knows that while simple graphics may not cut it on the shelves any more, they're no barrier to a satisfying gaming experience. For more info on graphics programming, check out our tutorial on creating graphics with OpenGL and the 3D rotations series at the advanced tutorial section of the site.
SpeedIf youre writing a game--particularly an arcade-style game--speed is all-important. Hardware advances have to some extent made optimization less relevant, but for every advance in hardware, an advance in graphics is sure to come along to take up the slack. And even a more simple game can run less than lightning-fast if it's written in an interpreted language like Java. Learning how to speed things up requires a familiarity with data structures and algorithms. Choosing the right data structure to store your game data in can mean the difference between a pokey game and one that zips along. For information on efficient game programming, see AI Horizon's article on efficient chessboard representation or algorithmic efficiency and big-o notation.
StructureNo matter what kind of program you're writing, from an implementation of Space Invaders to a filing system for grandma's recipes, clear programming structure is vital when it comes to understanding your code when you come back to work on it after a break, or, even moreso, if you plan on working with a buddy who has to be able to understand what you wrote or use your functions. Good commenting and readable style are a must. Games are also well-suited to object-oriented programming, since the elements of your game world are often, well, objects, like a spaceship, a bullet, or an evil alien vessel. Choosing classes appropriately is key, and inheritance can often come in handy (for example, if your game has several different light sources, or monsters, or doors, that all share some basic properties.) For more tips on style, see how and why to comment, thinking about programming, and this series on programming style.