WEBVTT 00:06.820 --> 00:08.050 Welcome back. 00:08.140 --> 00:10.000 Now we have some basic behavior. 00:10.000 --> 00:15.970 We still have a ways to go, but we know that our melee attackers will continue walking in closer. 00:15.970 --> 00:18.730 And as soon as they get here, they attack. 00:18.760 --> 00:26.260 Now, I'd like them to attack and then kind of shuffle around or move around to a different location 00:26.260 --> 00:28.750 around their target aura. 00:28.900 --> 00:34.170 So that way they don't just stand there in one location and just swing away and swing away. 00:34.180 --> 00:39.880 If they swing, then I'd like them to move around over to here and swing and move around over to here 00:39.880 --> 00:40.660 and swing. 00:40.660 --> 00:42.340 And I'd like that to be random. 00:42.340 --> 00:44.890 So that's what we're going to take care of in this video. 00:45.040 --> 00:49.330 Now, another thing, if we press play, take a look at the melee attacker. 00:49.330 --> 00:52.680 As soon as it reaches that point, there's a little pause. 00:52.690 --> 00:58.810 That point is 500 units away because they're in this branch move to Target. 00:58.810 --> 01:05.650 But as soon as they're no longer far enough to be approaching using this branch, then am I close enough 01:05.650 --> 01:06.310 to attack? 01:06.340 --> 01:07.580 Is suddenly true. 01:07.580 --> 01:13.040 And then they're using this move to get close and there's a little bit of a jerk. 01:13.040 --> 01:14.720 It's very slight. 01:14.720 --> 01:19.460 It's hardly noticeable, but you can see that he kind of jerks a little bit. 01:19.580 --> 01:21.260 Now that can be fixed. 01:21.290 --> 01:23.660 We can take a look at his blend space. 01:23.660 --> 01:28.370 So I'd like to really quickly just take a look at that before moving on. 01:28.610 --> 01:38.990 So we have blueprints and character and we can go to Goblin Spear and in AVP, Goblin Spear, we can 01:38.990 --> 01:45.920 take a look in the asset override to see where it's idle walk, run, blend space is. 01:45.920 --> 01:46.580 It's here. 01:46.580 --> 01:48.230 We can browse to that and here it is. 01:48.230 --> 01:50.360 It's in its animations sphere. 01:50.360 --> 01:54.140 I'm going to go into this and change the blend settings just a bit. 01:54.170 --> 02:03.350 Now the blend space uses a weight speed and this is kind of an interesting way to handle this, but 02:03.350 --> 02:07.670 it's basically the speed at which the sample weights are allowed to change. 02:07.670 --> 02:14.900 So in other words, if we change this value, we can make that jerkiness a little less jerky, a little 02:14.900 --> 02:15.830 smoother. 02:15.980 --> 02:21.290 Now we see that a speed of one means the sample weight can change from 0 to 1 in one second. 02:21.320 --> 02:23.870 A speed of two means that this would take half a second. 02:23.870 --> 02:29.300 So the higher the value, the faster we're going to blend between our sample weights. 02:29.300 --> 02:32.270 That's those inputs for that blend space. 02:32.270 --> 02:36.800 So if I put a value of four, then it'll take a quarter second. 02:37.210 --> 02:39.040 And we should see that jerkiness. 02:39.070 --> 02:40.480 Be a little smoother. 02:42.320 --> 02:44.120 In fact, there is no jerkiness. 02:44.120 --> 02:45.500 There's a slight pause. 02:45.530 --> 02:46.940 I'm okay with a slight pause. 02:46.940 --> 02:48.020 I'm fine with that. 02:48.020 --> 02:49.880 I just don't want jerkiness. 02:50.760 --> 02:52.110 So that looks great. 02:52.110 --> 02:56.460 And I think a value of four for weight speed is perfect. 02:56.490 --> 03:00.570 We can even add that for our slingshot goblin. 03:00.600 --> 03:05.500 That way, if they ever stop and start again, they don't do so jerkily. 03:05.520 --> 03:07.500 So I'm going to go ahead and close out of those. 03:07.530 --> 03:09.110 That takes care of those. 03:09.120 --> 03:12.570 But now for this, finding a new location business. 03:12.570 --> 03:19.520 So when my melee attackers get close and attack, I want them to attack and then find a new location. 03:19.530 --> 03:24.720 And this on screen debug message here is going to be quite annoying. 03:24.720 --> 03:32.730 So what I can do is just go into my Bet service, find nearest player and we can take away that on screen 03:32.730 --> 03:33.810 debug message here. 03:33.810 --> 03:35.560 We don't need that anymore do we? 03:35.580 --> 03:38.340 So next time we compile that will be gone. 03:38.640 --> 03:40.890 Now back to the task at hand. 03:40.890 --> 03:42.290 We need a task, right? 03:42.300 --> 03:44.430 We need a behavior tree task. 03:44.460 --> 03:48.690 We want one for finding a new location around the player. 03:48.720 --> 03:50.860 Now, this is a simple task. 03:50.860 --> 03:54.130 No need to go through the trouble of making one in C plus plus. 03:54.160 --> 03:57.520 Now that we know how to do that, that's an option. 03:57.520 --> 04:04.930 I'm going to make it in blueprint and I'm going to have a new blackboard key for a location for our 04:04.930 --> 04:09.130 AI to move to that's going to be different than Target to follow. 04:09.130 --> 04:09.670 Right? 04:09.670 --> 04:14.020 Because if they're moving to their target to follow, they're moving towards aura. 04:14.020 --> 04:19.210 And as soon as they reach it and attack, I want to find a new location that's different than the target 04:19.210 --> 04:20.080 to follow. 04:20.110 --> 04:25.390 I want a vector location somewhere in the vicinity around Aura. 04:25.420 --> 04:27.580 So I'm going to add a new blackboard key. 04:27.610 --> 04:34.180 We're going to go to Blackboard, add new Key, and we're going to use a vector and I'm going to call 04:34.180 --> 04:41.170 this vector move to location and we're going to set that move to location with a task here. 04:41.170 --> 04:43.840 So I'm going to make a new behavior tree task. 04:43.840 --> 04:49.150 So I'm going to click the dropdown for new task and we can choose one of our tasks. 04:49.180 --> 04:55.090 BT Attack is the Blueprint version and BT task attack is the C plus plus version. 04:55.090 --> 04:58.990 Notice it shows the full C plus plus name minus the U. 04:58.990 --> 05:01.630 And then we have BT Task Blueprint Base. 05:01.630 --> 05:06.490 That's what I'm going to choose and we're going to choose to save it here in our AI folder. 05:06.490 --> 05:08.580 And I'm going to call this BT. 05:09.190 --> 05:16.240 I'm going to use the convention BT without the full task to signify that this is a blueprint task and 05:16.240 --> 05:20.980 I'm going to call this BT go around Target. 05:20.980 --> 05:27.400 So I'm going to go ahead and save it there and here in BT, go around Target, I'm going to use event, 05:27.400 --> 05:33.100 receive, execute AI and we're also going to need to call, finish, execute. 05:33.850 --> 05:37.570 And in between here is where we're going to make things happen. 05:37.570 --> 05:41.920 Now I'm going to want a blackboard key selector so that I can set its value. 05:41.950 --> 05:46.000 We're going to want to set that value for move to location. 05:46.000 --> 05:53.980 So here in BT, go around Target, I'm going to add a new variable and change its type to blackboard. 05:54.580 --> 06:04.870 Key selector, and I'm going to call this new location and we can link this up with our move to location 06:04.870 --> 06:05.550 here. 06:05.560 --> 06:13.330 If we drag off of this and add the task, the task is go around target and if we click on it and select 06:13.330 --> 06:13.750 it. 06:14.280 --> 06:15.630 We can set it here now. 06:15.630 --> 06:16.830 We don't see it yet. 06:16.860 --> 06:20.730 We have to go back and open the eye icon and compile. 06:21.060 --> 06:26.520 And once we do that, we can go back to our behavior tree and see new location and we can link it up 06:26.520 --> 06:28.440 with our move to location here. 06:28.560 --> 06:35.100 Once we've done that here in go around Target, we can set the value of new location. 06:35.220 --> 06:38.520 So how do we set the value of new location? 06:38.520 --> 06:45.480 Well, we're going to need to find a new location around our enemies Target. 06:45.510 --> 06:49.050 Now, the enemy doesn't know what its target is. 06:49.050 --> 06:50.490 Exactly, does it? 06:50.520 --> 06:51.990 Well, it kind of does. 06:51.990 --> 06:55.060 It has a target to follow, which is an object. 06:55.080 --> 07:00.590 So that's another thing that we can sort of link up with one of our blackboard keys. 07:00.600 --> 07:05.150 We can have a new blackboard key selector for the target. 07:05.160 --> 07:08.970 So I'm going to add a new blackboard key selector called Target. 07:09.120 --> 07:11.730 I'm going to open the eye icon compile. 07:11.730 --> 07:19.780 And in our go around target task node, I'm going to set target to be linked up with target to follow. 07:19.780 --> 07:25.690 Now we have access to target to follow here in our task and it's a good idea to make sure that that's 07:25.690 --> 07:27.070 a valid target. 07:27.190 --> 07:30.640 So what we can do is get our target blackboard key selector. 07:30.670 --> 07:40.090 We can get the value of that blackboard key selector by using get blackboard value as and we can choose, 07:40.090 --> 07:43.030 we can choose actor, we can choose object. 07:43.030 --> 07:49.210 And we know if we go into our blackboard and select target to follow that its base class is actor. 07:49.210 --> 07:52.870 So get blackboard value as actor makes sense. 07:53.560 --> 07:57.220 So we're going to use get Blackboard value as actor. 07:57.250 --> 08:02.950 We're going to get that return value which is an actor and I'd like to use is valid to make sure that 08:02.950 --> 08:04.750 it is indeed valid. 08:05.220 --> 08:07.170 So this should be aura, right? 08:07.170 --> 08:14.640 And as soon as we have aura, if it's valid, we can get auras location with get actor location. 08:17.610 --> 08:19.020 What are we going to do with that? 08:19.020 --> 08:25.710 Well, we want to find a new location that's somewhere around Ora's actor location. 08:25.710 --> 08:29.340 But we want this new location to be navigable. 08:29.340 --> 08:33.030 We want it to be a reachable point in our nav mesh. 08:33.030 --> 08:38.610 We don't want to try to get any random location that could be in some hole in the nav mesh. 08:38.610 --> 08:39.090 Right? 08:39.090 --> 08:41.820 If I press P and look at our nav mesh. 08:42.470 --> 08:44.310 Let's say we're close to this pillar. 08:44.330 --> 08:48.880 We don't want a random location that could be somewhere in this hole. 08:48.890 --> 08:56.330 We want it to be a navigable point, which means it's in the green area somewhere we can actually reach. 08:56.540 --> 09:00.710 So the way we can do that is with the function. 09:00.710 --> 09:06.170 Get random location in navigable radius. 09:06.350 --> 09:10.010 This lets us choose a origin. 09:10.010 --> 09:12.050 We're going to use Ora's location. 09:12.050 --> 09:21.440 That's that actor location and some radius, some float value that determines how far away this random 09:21.440 --> 09:22.300 point can be. 09:22.310 --> 09:24.050 I'm going to use 300. 09:24.050 --> 09:26.480 In fact, I can promote this to a variable. 09:27.500 --> 09:29.180 And call this radius. 09:29.180 --> 09:34.940 I can even expose it with the eye icon and we can set this to a default value. 09:34.970 --> 09:37.370 I'll set it to a default of 300. 09:37.370 --> 09:44.000 And then because it's exposed, we could even go back to our behavior tree and we can set the radius 09:44.000 --> 09:45.080 here if we like. 09:45.080 --> 09:46.220 So that's handy. 09:46.250 --> 09:51.650 Now, if the actor's valid, we're going to do this and we're going to take that random location that 09:51.650 --> 09:52.730 we get from it. 09:52.730 --> 09:59.000 And what I'd like to do is set the blackboard value of our new location. 09:59.000 --> 10:05.060 So we're going to get that blackboard key selector and we're going to drag off of it and set blackboard 10:05.060 --> 10:07.040 value as vector. 10:08.850 --> 10:11.250 And we're setting it to that random location. 10:12.020 --> 10:13.130 Like so. 10:13.340 --> 10:18.950 And once we're done with that, we're going to finish, execute and return success. 10:18.980 --> 10:22.910 Now get random location in navigable radius could fail. 10:22.910 --> 10:27.080 And really, in that case, maybe we could just pass a failure in here. 10:27.080 --> 10:32.960 So we're going to go ahead and just add a reroute node here and here and just pass that straight in. 10:32.960 --> 10:35.240 And I think that will be fine. 10:35.330 --> 10:42.920 So now we have this go around target task that will get a random point in the navigable radius. 10:42.950 --> 10:49.910 We can go back in here and as soon as we get that random point, now we have this move to location set. 10:49.910 --> 10:53.510 It should be and we can move to that location. 10:53.630 --> 10:56.390 So we're going to drag off of our sequence. 10:56.390 --> 10:58.340 We're going to use another move to. 10:58.340 --> 11:04.060 And for this move to we're going to set the blackboard key to our move to location. 11:04.070 --> 11:07.370 Now we're moving to that random point around the target. 11:07.370 --> 11:13.530 And after attacking, I'd like just a little bit of a delay, maybe a second plus or minus half a second, 11:13.530 --> 11:14.520 something like that. 11:14.520 --> 11:17.730 So after the attack, let's do a wait node. 11:17.730 --> 11:24.660 And for this wait, we're going to have a wait time of one second plus or -0.5. 11:24.990 --> 11:30.390 So there will be an attack and a little delay and then we'll move around the target. 11:30.420 --> 11:37.770 Now, the thing about moving to a random location is we've seen that our enemy could get a bit stuck. 11:37.800 --> 11:42.690 It could have other enemies in the way those don't create holes in the nav mesh after all. 11:42.690 --> 11:47.550 So if we get hung up on this task too long, I want to abort. 11:47.550 --> 11:49.470 And we can do that with a decorator. 11:49.470 --> 11:51.750 I can right click, add decorator. 11:51.750 --> 11:54.780 And there's a special decorator called Time Limit. 11:54.780 --> 11:58.770 If I select that, then the time limit lets me abort. 11:58.770 --> 12:05.520 If the enemy's been struggling a little too long on this move too, so I'll have this set to observer 12:05.520 --> 12:06.810 abort self. 12:06.810 --> 12:08.970 So we'll abort the self. 12:08.970 --> 12:12.360 That's this specific move to node here. 12:12.360 --> 12:19.980 It can abort itself and we won't be stuck in limbo here and the time limit can be something like two 12:19.980 --> 12:20.520 seconds. 12:20.790 --> 12:26.460 So if we're trying to move to a new location around the target, if that takes longer than two seconds, 12:26.490 --> 12:29.880 we'll go ahead and abort and then we can try things again. 12:29.880 --> 12:35.430 So let's see how our go around target works and we can of course change the name of this node. 12:35.430 --> 12:39.540 I'm going to call it find new location around Target. 12:39.960 --> 12:41.940 Let's see how this is going to work. 12:41.940 --> 12:48.150 Let's go back, press play, and we'll see how our melee character behaves. 12:48.150 --> 12:49.230 Attack. 12:49.230 --> 12:50.700 Couple of seconds delay. 12:50.700 --> 12:51.720 Oh, it attacked again. 12:51.720 --> 12:52.560 It moved. 12:52.590 --> 12:53.820 It moved again. 12:53.820 --> 12:58.800 And notice that it moves to a new location, but then it comes in close again. 12:59.580 --> 13:03.590 So this gives it a little bit of a more aggressive behavior. 13:03.600 --> 13:05.550 And of course, we can change parameters. 13:05.550 --> 13:09.750 We can change that radius of the random point and so on. 13:09.750 --> 13:17.430 We can also test this out really close to a pillar here and we'll see that it should not get stuck. 13:17.460 --> 13:23.640 And if it does ever get stuck, there's a two second time limit and it'll go ahead and just abort that 13:23.640 --> 13:27.300 move to for moving to a random location. 13:28.170 --> 13:33.080 So this gives us a little bit more of some frantic behavior for our enemy. 13:33.090 --> 13:34.500 It's going to attack. 13:34.530 --> 13:36.900 It's going to try to find a new location. 13:36.900 --> 13:39.660 Notice it got stuck there because it was trying to move through. 13:39.660 --> 13:43.110 Ora Ora doesn't create a hole in the nav mesh either. 13:43.110 --> 13:51.000 So if it's trying to move and it's stuck after two seconds, we go ahead and try to find another location 13:51.000 --> 13:52.710 after attacking again. 13:52.950 --> 13:56.520 So this gives us a little bit of some safety. 13:57.810 --> 13:59.730 Okay, so that's looking great. 13:59.760 --> 14:02.220 Now, our attack is still pretty boring. 14:02.220 --> 14:08.220 It's still just drawing a debug sphere, but at least we know when it's attacking, when we see those 14:08.220 --> 14:17.040 red spheres and we know that after attacking, there's a second and a new location is found which we 14:17.040 --> 14:23.880 abort if it takes longer than two seconds to do so and we find a new location and attack again. 14:24.120 --> 14:25.050 Excellent. 14:25.080 --> 14:26.940 So this is looking pretty good. 14:26.940 --> 14:32.220 We still do need to actually have our enemies attack and we'll get to that. 14:32.220 --> 14:35.640 But we also want some behavior for our ranged attackers as well. 14:35.670 --> 14:35.970 Right. 14:35.970 --> 14:37.500 They get to attack, too. 14:37.530 --> 14:40.590 So we'll get to those things in the videos to come. 14:40.590 --> 14:43.380 For now, great job and I'll see you soon.