Flash MX 2004 Games : Art to ActionScript

Flash MX 2004 Games
The example we are going to study in this chapter is deliberately kept very simple. There is a lot
to learn when understanding sockets and so your time is better spent understanding the principles
rather than getting bogged down in the intricacies of the game design. In the example there are
up to eight boxes. A user can click and drag any unused box. When a box is being dragged, it
will be seen moving on the screen of every other computer connected to the site. If a user has
entered their name in the box at the top, then their name will be displayed in the box. Very simple
maybe, but it illustrates the concepts of multiple users receiving and passing data in real-time across
a remote network. Before we can create the Flash application we need a program to be running
on the server. This program acts as the conductor for all the connected computers. We are going
to create this program using Visual C++.
Sockets on a Windows server
This section is going to use C++ code. The syntax
for C++ is very similar to the JavaScript syntax you
are familiar with from using Flash ActionScript. We
are going to use something called Microsoft Foundation
Classes. This is a library of C++ classes (another word
for objects) that make programming Windows applications
easier and more robust. To make use of the example
on the CD, you will need a copy of Visual C++ on
a PC. If you can, open the file ‘Examples\Chapter22\
SockListener\SockListener.dsw’. This file is a Visual C++
project file. A C++ project uses several files to store the
source code and other information required by the IDE
(Integrated Development Environment) to compile the
program. The source we will examine is in the file ‘Sock-
ListenerDlg.cpp’, which is simply a text file; so if you don’t
have Visual C++ then just open this in a text viewer. MFC
applications come in several flavours; this one uses a dialog
box as the main window. Figure 22.2 shows the applica-
Figure 22.2 The SockListener
application
tion running. Visually the program is just a list box where we can add text information that makes
understanding the program’s operation easier. The purpose of the program is to open a server
socket on a defined port on a computer with a static IP address and listen for users across the
Internet who want to connect to this socket. Whenever there is a new connection it is stored in a
list and the program sees to it that all the current listeners to this socket get fed with information.
The example program allows remote users to move boxes on another user’s computer and vice
versa.
Initializing the dialog box
Whenever a new dialog box is created, MFC calls the function ‘OnInitDialog’ in the dialog box
class. Most of this is standard to all dialog boxes; a menu is created and the icon for the application
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