Mission Two – Testing a Player's Learning - Creating E-Learning Games with Unity - page 190

public class condition_onEnter :
npcCondition;
10. Give the condition_OnEnter class a public reference to a GameObject
called trackObj . This will hold a reference to the most recent GameObject
that enters the trigger volume. This can be done with the following line of
code:
public GameObject trackObj;
11. Add a private Boolean variable named hasEntered , and initialize it to
false . This will be used to track whether an object is actually inside the
volume (rather than only having entered this frame):
private bool hasEntered = false;
12. Now recall that the OnTriggerEnter / OnTriggerExit callbacks are re-
turned from the physics system rather than our DecisionMgr system. In order
to interface the two, we will implement OnTriggerEnter and OnTrigger-
Exit and then pass the relevant information outward.
13. The OnTriggerEnter method should simply set hasEntered to true ,
and it should set trackObj to other.gameObject as shown in the follow-
ing code snippet:
void OnTriggerEnter(collider other)
{
hasEntered = true;
trackObj = other.gameObject;
}
14. The OnTriggerEnter method should conversely set hasEntered to
false , and it should nullify trackObj as shown in the following code snip-
pet:
void OnTriggerExit(Collider other)
{
hasEntered = false;