793than 0.5 to be converted to false, and any value greater than or equal to 0.5 to
be converted to true. This is the essence of GUI-based event systems like Un-
real Engine 3’s Kismet. A screen shot of Kismet is shown in Figure 14.19.
14.7.11.2. Some Pros and Cons of GUI-Based Programming
The benefi ts of a graphical user interface over a straightforward, text-fi le-
based scripting language are probably prett y obvious: ease of use, a gradual
learning curve with the potential for in-tool help and tool tips to guide the
user, and plenty of error-checking. The downsides of a fl ow-chart style GUI
include the high cost to develop, debug, and maintain such a system, the addi-
tional complexity, which can lead to annoying or sometimes schedule-killing
bugs, and the fact that designers are sometimes limited in what they can do
with the tool. A text-fi le based programming language has some distinct ad-
vantages over a GUI-based programming system, including its relative sim-
plicity (meaning that it is much less prone to bugs), the ability to easily search
and replace within the source code, and the freedom of each user to choose the
text editor with which they are most comfortable.
14.7. Events and Message-Passing
Figure 14.19. Unreal Engine 3’s Kismet.