Section 21.2. Internet Requirements

21.2. Internet Requirements

There are a couple of important requirements when supporting a web-based game from within the browser. The first is the Internet communication. Will your game require broadband-type speeds to function correctly, or will any Internet connection speeds suffice? Only you can answer this question. However, there is a factor that could narrow down the answer. The genre of game can dictate the types of communication required: strategy-based games would require much less bandwidth back and forth between client and server than an FPS game would. So, look at the type of game you plan to build, and think about the connection requirements you think you will need based on the amount of client/server communication necessary.

The more important Internet requirement is what the game's platform will be. This requirement boils down to two choices: one of an assortment of plug-ins, or JavaScript with Ajax.

21.2.1. Plug-ins

There are few choices when it comes to plug-ins for browsers, and I am going to throw applets into this definition as well. Each type of plug-in has its advantages, of course, and the biggest disadvantage with all plug-ins is that they require a user to download software for them to work. The plug-ins that I will focus on are:

• Flash

• Shockwave

• Java applets

21.2.1.1. Flash

Perhaps the most popular plug-in for browsers today is Flash. This could be because its interoperability within a browser has become nearly seamless. Whole sites are built using Flash to create all functionality and content. Media sites, especially those for movies, use Flash to allow more user interactivity.

Macromedia released Flash in 1996, after acquiring the technology from FutureWave Software. Adobe acquired Macromedia and its software in December 2005, and the current version of Flash is Flash CS3. Originally developed as a multimedia platform for the World Wide Web, Flash has grown and become a tool for user interaction, as well as a platform for games and complicated presentation that is much more difficult to produce using XHTML, CSS, and JavaScript. Flash uses the ActionScript programming language, which has the same syntax as JavaScript, as it is an implementation of ECMAScript. ActionScript allows a developer to interact with all of the objects created within Flash, as well as communicate with a server.

Flash is a small browser download, and according to Adobe's web site, it's available on nearly 99 percent of Internet-enabled desktops.^[10] This makes it a good candidate for game development, and an alternative for web developers who have JavaScript experience. In fact, Ajax can be implemented within a Flash platform, as Flash uses ActionScript behind the scenes. ActionScript is a close cousin to JavaScript, and it follows ECMAScript more closely. Flash can be a good alternative for more complicated games in which you still wish to implement Ajax for communication between the client and the server.

^{[10] *} Flash Player Statistics from Adobe Systems (http://www.adobe.com/products/player_census/flashplayer/)

21.2.1.2. Shockwave

Macromedia Director was introduced before Flash. It was followed shortly after by Shockwave, which Macromedia introduced around the same time as Flash, and although both are from the same company, Shockwave was a direct competitor to Flash. Shockwave was geared more toward game development from the start, having a more powerful graphics engine. This made it a larger plug-in, however, and its size kept it from enjoying the same widespread adoption as Flash. Shockwave's other limitation is that it is not compatible with all operating systems—in particular, Linux.

As noted earlier, Adobe bought Macromedia and all its products in 2005. The current version of Shockwave is 10.2.

Today's Shockwave is well suited to games, as it renders faster, includes hardware-accelerated 3D images, and offers blend modes for layered display of graphical assets. This allows it to build much more graphically rich games, something Flash cannot do. The trade-off is its lack of support for operating systems other than Windows and Mac OS X, its larger initial download size, and its slower startup time in browsers.

21.2.1.3. Java applets

Java applets are specialized Java programs intended to run within browsers as plug-ins. The browser's operating system must have a compatible version of the Java Runtime Environment (JRE) for applets to function correctly. The most recent version of the JRE at the time of this writing is JRE 6 Update 2.

You create an applet by extending a new class for the program with the Applet class. Any other classes supported by the JRE on the client can be used in the applet. The advantage is that you can build a pretty robust gaming application to run in the browser. Just remember that the larger and more complex the application, the larger the size of the file that the browser must download.

Java applets can be well suited for games, as they have Java's graphing capabilities and the ability to handle network connections not available using Ajax. The only thing to remember is that the user must have the JRE associated with your build of the applet. This download may take a very long time, though, if the user doesn't have a compatible version of the JRE already installed. This may turn people away from using your gaming applet.

21.2.2. Game Development with Ajax

Ajax solutions to browser-based game programming have the advantage of complete browser reliance without the need for any additional software. This can improve startup times and give a completely seamless look within the browser. The real advantage over plug-ins for game programming is that there is nothing else new to learn.

An Ajax solution for game development must rely on XHTML, CSS, JavaScript, and XML/JavaScript Object Notation (JSON). Do these skills sound familiar? They ought to, as they are the skills that every developer should possess. What's more, they are the skills that you either knew before reading this book, or hopefully have gained by now. This can be appealing to a developer who has always wanted to program a game, but has lacked the skills to create one on a traditional platform (i.e., the desktop).

So that you can better understand the parts of a typical game, I will break them down in a modular manner, as each component of the game will need its own Ajax functionality. The parts that we will be interested in are:

• Character animation

• Collisions

• Input

Putting all of this together will result in a rough game client that can communicate with a server and handle the basic functionality most games need.