WEBVTT 00:06.910 --> 00:08.200 Welcome back. 00:08.230 --> 00:14.140 Now we've created our attribute system and we've created a couple of gameplay abilities. 00:14.170 --> 00:16.840 One, offensive ability, the Firebolt. 00:16.840 --> 00:19.600 And we have hit React for our enemies. 00:19.600 --> 00:24.100 But of course, our enemies are going to want to do much more than just hit react. 00:24.100 --> 00:30.130 And we still do want to create a lot more abilities, more offensive abilities, attacks. 00:30.130 --> 00:33.760 That aura can use, different types of spells and so on. 00:33.760 --> 00:39.520 But at this point in the course, it's time for our enemies to start having more functionality, more 00:39.520 --> 00:44.350 behavior as they need to be able to react to things they need to attack. 00:44.380 --> 00:48.460 Aura needs to be able to take damage from the enemies. 00:48.460 --> 00:54.250 And once we kill the enemies, we need to start gaining experience and think about how we're going to 00:54.250 --> 00:56.860 level up and reward the player. 00:56.860 --> 01:03.040 So amongst all that, the enemy needs some sort of way to be controlled by AI. 01:04.040 --> 01:06.050 So we have our aura enemy. 01:06.050 --> 01:10.900 And this class so far does nothing but just stand there. 01:10.910 --> 01:14.030 Yes, it can hit react, but that's it. 01:14.060 --> 01:21.170 Now it needs a way to make decisions, a way for it to process logic based on what's going on. 01:21.170 --> 01:26.750 It needs a way to chase aura so that it can decide when to attack. 01:26.750 --> 01:31.790 And we could place all of that logic in C plus plus code if we wanted to. 01:31.790 --> 01:35.060 But another way is to use behavior trees. 01:35.150 --> 01:44.600 A behavior tree is a nice way to encapsulate AI behavior into a nice tree blueprint where we can easily 01:44.600 --> 01:48.110 see the control flow of AI logic. 01:48.350 --> 01:57.620 We can also tie this in to the enemy via interface function calls or even to the ability system by sending 01:57.620 --> 02:01.790 gameplay events, activating abilities and so on. 02:02.030 --> 02:06.150 So a behavior tree is a pretty good way to control the enemy. 02:06.150 --> 02:12.930 And if we have a behavior tree asset tied to the enemy class itself, then different enemies could potentially 02:12.930 --> 02:14.280 use different behavior. 02:14.280 --> 02:14.640 Trees. 02:14.640 --> 02:17.100 They could all share the same behavior tree. 02:17.100 --> 02:22.740 Or we could make this flexible so they can swap that behavior tree asset out. 02:22.860 --> 02:29.490 Now, in addition to a behavior tree, AI enemies are going to need an AI controller, so this class 02:29.490 --> 02:32.370 will be closely tied to the enemy. 02:32.370 --> 02:39.060 And if we're going to be using a behavior tree, then something somewhere needs a behavior tree component 02:39.060 --> 02:41.700 and something called a blackboard. 02:41.730 --> 02:47.580 The behavior tree and the blackboard are classes that work closely together with each other. 02:47.580 --> 02:52.920 We'll see how and these components should be on some class. 02:52.950 --> 03:00.600 I'm going to choose to put them on the AI controller class so the AI controller will own these components. 03:00.600 --> 03:07.020 But the AI controller needs to be told what behavior tree its behavior tree component should use. 03:07.020 --> 03:11.640 So the behavior tree component is the component that contains the behavior tree. 03:11.670 --> 03:18.180 Our enemy specifically will have that and it's going to have to tell the controller to use its specific 03:18.180 --> 03:19.170 behavior tree. 03:19.170 --> 03:25.350 And once that behavior tree component knows which behavior tree it should use, it needs to run that 03:25.350 --> 03:26.430 behavior tree. 03:26.460 --> 03:29.580 So we need to start that behavior tree and get it going. 03:29.580 --> 03:34.560 And we can do that by calling run behavior tree on the AI controller. 03:34.770 --> 03:41.580 So the AI controller, as well as the behavior tree and blackboard are classes that don't exist in our 03:41.580 --> 03:42.630 project yet. 03:42.630 --> 03:44.730 So we have some things we need to make. 03:45.250 --> 03:48.100 So we have some next steps to perform. 03:48.250 --> 03:54.130 We need an AI controller class and we need to create a blackboard and a behavior tree. 03:54.160 --> 04:00.670 Now our AI controller is going to own the components for these, so we need to add a blackboard component 04:00.670 --> 04:04.090 and a behavior tree component to the AI controller. 04:04.120 --> 04:11.520 Once the AI controller has these components, then we need to add a behavior tree to our aura anime 04:11.530 --> 04:17.230 and we can set this in blueprint so we can potentially swap it out for different types of enemies if 04:17.230 --> 04:18.190 we need to. 04:18.190 --> 04:24.340 And once we've tied all this together, we need to actually run the behavior tree so that it's running 04:24.340 --> 04:27.130 and controlling our AI enemies. 04:27.130 --> 04:33.580 So once we get all of this foundational setup in place, then we can start deciding how our enemies 04:33.580 --> 04:37.570 are going to behave and start filling out our behavior tree. 04:37.720 --> 04:41.700 So we'll start tackling items on this list in the next video. 04:41.710 --> 04:42.880 I'll see you soon.