Ultimate Game Design : Building game worlds

Building Game Worlds
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U L T I M A T E G A M E D E S I G N
(www.ngweb.biz/software/djsedit.shtml), while others build custom script systems
into a complete stand-alone tool. In the latter case, right-clicking an actor in a scene
might bring up a series of “property” editing tabs that can be used to specify a number
of details for selected actors. Some examples of these properties include
� Actor’s patrol speed (How fast does the actor move in protecting a
boundary?)
� Actor’s patrol shape (Does the actor walk a box perimeter, a semicircle,
or a custom shape?)
� Actor’s hostility towards other actor types (Friend or foe? Attack or defend?)
� Actor’s default offensive weapon choice (Laser fire? Space baton?)
� Actor’s default defense (Use shield, roll into a ball, or self-destruct?)
� Actor’s default wait-state (Tap foot, sit down, or rub eyes?)
� Actor’s inventory specifics (Order of item use? Weapon priority?)
� Actor’s response to attack (Fight till death, fight till damage = 80 percent,
or fight till out of ammo?)
� Actor’s specialized orders (Seek another actor, seek map position, seek level
midpoint, seek ammo cache, return to camp, band together with closest similar
actor, play cards/dice [or other humor element], summon help, cloak or hide,
shadow or follow another actor, chase distraction, search for something until
the search condition is met?)
The properties listed here, as examples, as well as a vast number of other actor
properties might be similarly editable in this fashion. You will often need tools programming
support from a tools programmer to set up each of the properties you wish
to edit, since ultimately your edits need to be reflected in the code when the game is
recompiled or rebuilt.
To provide you with a sample of what different scripting languages look like, this
section translates a simple monster behavior script into JavaScript, Visual Basic,
Python, and Perl. Throughout this chapter, I’ll show scripts in JavaScript most of the
time, because it’s a well-supported scripting language with editors freely available,
but Visual Basic and Python are also gaining in popularity.
This script calls for the monster to attack the player if it sees the player, to pick up a
weapon if it sees the weapon, and otherwise to simply patrol.