Game Development Reference
In-Depth Information
Sensors
Using the Mecanim state machine in this way is very powerful and just having scripts up-
date the parameters of the state machine through input (user taps a key, or scene loads) is
simple enough. However, if you want reactive AI, you might want to think about sensors.
Sensors are effectively the AI's eyes and ears and whatever else it wants to use to detect ac-
tion within a scene (even if it's an alarm or trip wire). Generally, they are self-contained
components that look after themselves and inform whatever they are attached to. They can
be as complex or as simple as you need them to be.
A basic sensor might be an empty game object with a trigger collider (the trip wire), which
tells the enemy state machine that the player has come into view. Alternatively, you could
use ray casting (yes, even in 2D) to check whether the target is in view.
One of the best examples of a sensor I've seen is a wandering game object with a sphere
trigger that wanders round the screen to represent the point where the enemy was looking
at. If it falls on the player or an object that has been moved in the scene, then all hell breaks
loose.
