Game Development Reference
In-Depth Information
9
.
For basic configuration settings, an INI file makes the most sense because
it's very simple and would therefore be easy for the end user to edit.
10
.
The two main components of UI add-ons in
World of Warcraft
are the lay-
out and the behavior. The layout is implemented in XML and the behavior
is implemented in Lua.
Chapter 12: Networked Games
1
.
The Internet Protocol is the base protocol that needs to be followed in or-
der to send any data over the Internet. The main difference between IPv4
and IPv6 is how the addresses are configured. In IPv4, addresses are a set
of four bytes, for a total of about four billion possible combinations. This
seemed like a lot when IPv4 was introduced, but in recent years addresses
have been running out. IPv6 increases the number of address combina-
tions to 2128, which means it will not run out of addresses any time soon.
2
.
ICMP, or Internet Control Messaging Protocol, is designed mostly for ac-
quiring status information about a network and connections. One use for
games, however, is the echo request/echo reply feature of ICMP. This al-
lows games to “ping” and determine the amount of time it takes a packet
to travel a round trip.
3
.
TCP is connection based, which means two computers have to perform a
handshake before any data can be transmitted. Furthermore, TCP guaran-
tees that all packets will be received—and received in the order they were
sent.
4
.
A port can be thought of a virtual mailbox. Each computer has approxim-
ately 65,000 ports for TCP and 65,000 ports for UDP. Certain ports are
traditionally used for certain types of data (such as 80 for HTTP servers),
but there is not necessarily a strict use of a particular number. The import-
ance of ports is that they allow multiple applications on the same com-
puter to be using the network without interfering with each other.
5
.
UDP is generally more preferable for real-time games because the addi-
tional guarantees that TCP provides might cause unnecessary slowdown.
A great deal of information is not mission critical and therefore should not
be resent if it's lost. But with TCP, everything will be resent until an ac-
knowledgement is received, which could substantially delay the data be-
ing processed if it's received out of order.
