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
Even simpler, we might just want to cause a couple of shafts of light to stream into
a room onto a relic, a magical sword, or a hero helper character. We can also use a
light trigger to build this behavior.
This sample shows how to create a spotlight on the hero helper when a player is
near them:
// JavaScript sample of "light" trigger support
if(player.nearHeroHelper()) {
createSpotlight(heroHelper);
}
BUILDING BEHAVIORS
You’ve now seen some basic script examples and experienced some of the power in
using triggers. Building behaviors often requires using a measure of both. It’s important
that you learn enough about scripting and triggers to combine their power together
into building behaviors. Let’s look at another example that demonstrates how you
would use trigger information to control entire groups of creatures.
Creature Creator
Sometimes you will want to use triggers to control the behavior of prop creatures for
pure visual effect. These might include insect swarms, flocks of birds, or schools of
fish. Depending on your script system specifics, sometimes you will use commandline
entries (like the sine wave attack pattern), and other times you will simply set
properties in a tool—properties that define how your trigger is going to behave.
So, suppose we set down a trigger of the type creature_creator. The kinds of properties
we might edit for its behavior include (but are not limited to) the following:
� The maximum number of creatures generated (let’s say, 10)
� Which type of creature will spawn? (We might have 15 choices here, bug_1,
bug_2, fish_1, fish_2, and so forth. Sometimes we can even spawn the same
trigger with two or more types—like two different kinds of bugs coming from
the same hive. We might “hide” the trigger inside a hive actor in the scene.)
� What is the spawn radius, in units? (How far around the trigger will these
creatures spawn?)
� What is the spawning rate or speed? (How fast will these creatures spawn?)
� What is the spawn life? (How long do these creatures “live” on the screen
before they die off or disappear?)