Game Development Reference
In-Depth Information
React AI
React AI doesn't come equipped with a patrol script, so we provided one. We'll start
with this behavior tree script and look at how it works and how to use it. Here are the
steps to reproduce it:
1. Create a patrol script.
2. Create a patrol AI.
3. Set up the NPC patrol.
To start with, we've provided a script for you to use. In it, I started with the last script
for pathfinding, and then I extended it to use a similar configuration to the patrol path
in Quick Path's patrol script. Here are a couple of key points about this script:
• It is based on the
FollowThePlayer
script from the previous chapter.
• You can find the code in the topic's contents at
\Scripts\React
AI\Patrol.cs
.
• It stores a public array of
Vector3
, so the
Inspector
UI can allow designers
to set the waypoints.
• Instead of the target being a player, it is set to the next waypoint in the list.
Once we are close enough, it selects the next waypoint.
Close Enough
is the
float field that allows the inspector to find it.
• If there are no waypoints left to select, it starts over at the first waypoint.
However, now we need to create the user endpoint. Right-click on a folder in the
Project
tab and choose
Create
|
Reactable
. Name the reactable
PatrolAI
. In its
Inspector
UI, add the patrol script as one of the behaviors. Next, right-click on the
PatrolAI
asset and select
Edit Reactable
.
In the reactable, right-click on the root element and select
AddBranch
|
Sequence
.
A sequence repeats all the steps in an order. Under the
Sequence
option, right-click
and navigate to
Add
|
Leaf
|
Action
. Assuming that you only added the patrol script
to its behaviors, it should automatically select
Patrol.Go
as its action. You can add
notes to each step to help write a better story of what the AI is doing. When it is this
simple, it does not matter so much, but many AIs will become more complex.
Next, the NPC needs to be set up to use this new patrol AI. Find the NPC in the previ-
ous chapter's React AI project. You'll need to remove the following AI that was on the
