WEBVTT 00:06.800 --> 00:07.840 Welcome back. 00:07.850 --> 00:13.760 So we have our elementalist behavior tree, and it's the same as our regular behavior tree for all of 00:13.760 --> 00:14.990 our other enemies. 00:14.990 --> 00:17.210 But we're going to want a few differences here. 00:17.210 --> 00:19.930 For one, I'd like my attack to be different. 00:19.940 --> 00:26.870 I want an attack that checks to see our number of minions, and if it's below a certain number, then 00:26.870 --> 00:31.340 I'd like to activate the summon ability to summon minions. 00:31.340 --> 00:38.420 For this reason, I'm going to double click on my ranged attack task node and browse to the folder that 00:38.420 --> 00:42.350 has this task so that I can duplicate this attack. 00:42.350 --> 00:48.410 I'm going to right click, I'm going to duplicate it and call this BT attack underscore Elementalist 00:49.100 --> 00:51.110 So we have an elementalist attack. 00:51.110 --> 00:55.160 Now I can close BT attack and open the Elementalist version. 00:55.160 --> 00:59.150 Now this version is going to be more specific to the Elementalist. 00:59.150 --> 01:04.730 And what I'd like to do is check right here before activating abilities. 01:04.730 --> 01:09.840 I'd like to pass in a tag that depends on some conditions. 01:09.840 --> 01:16.140 I want to see how many minions the enemy has and then we can try activate abilities with the tag that 01:16.140 --> 01:17.310 we set. 01:17.310 --> 01:20.520 So I'm going to make a tag for summoning. 01:20.520 --> 01:22.080 So we have an attack tag. 01:22.080 --> 01:26.010 I want a summon tag as well, so I'm going to add a new variable. 01:26.010 --> 01:28.170 I'm going to call this summon tag. 01:28.740 --> 01:33.600 It's going to be a gameplay tag, so we'll change it to gameplay tag for its type. 01:34.240 --> 01:39.580 And I'm going to compile so I can give this a default value of abilities dot summon. 01:39.820 --> 01:44.470 And then I'm going to make another variable called ability tag. 01:45.190 --> 01:50.050 And this one will not be set until we check some conditions. 01:50.050 --> 01:54.250 So I'd like to check some conditions after we set a combat target. 01:54.280 --> 01:58.630 Now, I really don't like this controlled pawn wire coming across here. 01:58.630 --> 02:01.090 It's making me feel like this is very messy. 02:01.090 --> 02:06.010 So I'm going to take my controlled pawn and I'm going to promote it to a variable called controlled 02:06.010 --> 02:07.240 pawn right here. 02:07.600 --> 02:12.700 And then we'll just use that variable instead of having these reroute nodes. 02:12.850 --> 02:16.270 So we'll put that there and we'll put it here. 02:18.700 --> 02:21.490 And then I'm going to delete these reroutes. 02:22.180 --> 02:25.130 So that's making me feel a little bit better. 02:25.150 --> 02:27.760 And I'm just going to straighten a couple things out. 02:28.330 --> 02:28.870 Okay. 02:28.870 --> 02:32.590 So we need to set our ability tag based on some conditions. 02:32.620 --> 02:39.640 I'd like to check the number of minions for our controlled pawn, so I'm going to right click and type 02:39.640 --> 02:40.360 get. 02:41.570 --> 02:42.980 Minion count. 02:43.160 --> 02:50.450 Now, this is on our combat interface and it needs to know the object that is supposedly who implements 02:50.450 --> 02:51.390 this interface. 02:51.410 --> 02:54.470 We're going to pass in our controlled pawn here. 02:54.800 --> 03:01.370 So after we get our minion count, we have something we can check and we can check against a number 03:01.370 --> 03:02.240 of minions. 03:02.240 --> 03:07.970 That should be a sort of threshold, and I think that can be a member variable of our attack task. 03:07.970 --> 03:13.340 So I'm going to add a new variable and call this minion spawn threshold. 03:14.570 --> 03:19.670 I'm going to change this to an integer compile and give it a default value. 03:19.670 --> 03:23.190 But we could change this if we check the eye icon to expose it. 03:23.210 --> 03:30.530 I'm going to set this to two and if we go down below to in other words, there's one minion left. 03:30.560 --> 03:32.720 Then we should spawn minions. 03:32.720 --> 03:34.880 We should activate the summon ability. 03:34.880 --> 03:37.970 So I'm going to check this minion count against our threshold. 03:37.970 --> 03:44.820 We're going to say if the minion count is less than our minion spawn threshold, which is two. 03:44.850 --> 03:51.450 So if minion count becomes one, then what we need to do is we need to spawn. 03:51.570 --> 03:56.150 We're going to have a branch here and we're going to spawn minions. 03:56.160 --> 04:03.210 In other words, if it's true, I want to set my ability tag here and I want to set it to my summon 04:03.210 --> 04:03.900 tag. 04:05.120 --> 04:06.590 So that's what we'll do. 04:07.340 --> 04:13.580 Now, if it's false, we're going to set the ability tag to the attack tag and that way we won't summon, 04:13.580 --> 04:15.180 but instead we'll attack. 04:15.200 --> 04:22.040 So in the true case, we're setting it to summon tag and the false case, we're setting ability tag 04:22.040 --> 04:24.410 to the attack tag. 04:26.240 --> 04:29.840 So all we're doing is setting the tag based on our condition here. 04:29.960 --> 04:31.400 I'm going to make some room here. 04:31.430 --> 04:37.790 Now, regardless of which one, both of these are going to go into the same try activate abilities by 04:37.790 --> 04:41.570 tag so they'll both go into that same node. 04:42.240 --> 04:48.120 The only difference is which tag we're going to use for trying to activate an ability. 04:48.940 --> 04:51.550 And that depends on minion spawn threshold. 04:51.640 --> 04:53.350 Now, here's the thing, right? 04:53.350 --> 04:58.990 We need to keep an updated minion count every time we spawn in a minion. 04:59.020 --> 05:02.160 That should increase our minion count. 05:02.170 --> 05:04.420 And what does get Minion count do? 05:04.450 --> 05:07.990 Well, we implemented this on the base character class. 05:07.990 --> 05:08.530 Right? 05:08.530 --> 05:13.570 Which means that we're returning a simple integer on the base character class. 05:13.570 --> 05:15.520 We're never actually updating that. 05:15.520 --> 05:22.420 So every time we spawn a minion, we need to set that minion count or at least increment it, right? 05:22.420 --> 05:29.890 So we should have a function on the combat interface to set the minion count, or at least increment 05:29.890 --> 05:30.820 the minion count. 05:30.820 --> 05:31.270 Right. 05:31.270 --> 05:32.940 Incremented by one. 05:32.950 --> 05:38.200 So I'd like to make that function and make sure we're updating our minion count before continuing. 05:38.200 --> 05:44.650 So I'm going to close the editor saving everything and we're going to go into our combat interface and 05:44.650 --> 05:49.040 let's just make a function to increment minion count. 05:49.040 --> 05:54.380 So I'm going to make it a void function and I'm just going to call it increment. 05:55.230 --> 05:56.460 Minion count. 05:56.640 --> 05:59.770 We're just going to increment it by one. 05:59.790 --> 06:04.780 Although we could pass in an integer if we want to increment it by more than one. 06:04.800 --> 06:10.910 And if we want to increment by one, just pass a one in there just because that's slightly more versatile. 06:10.920 --> 06:11.880 I'm going to do it. 06:11.880 --> 06:19.290 I'm going to have an int 32 called amount and we can override this and or a character base. 06:19.290 --> 06:25.410 So where we have our get minion count, we're also going to override increment minion count. 06:25.560 --> 06:34.320 So virtual void increment minion count implementation override. 06:34.350 --> 06:43.260 Let's generate the definition and we're going to take our minion count plus equals amount. 06:43.500 --> 06:52.200 So now we have the ability to increment our minion count and we could pass in a negative value if we 06:52.200 --> 06:55.030 need to decrement that minion count. 06:55.030 --> 07:00.460 And that actually raises a question how are we going to decrement the minion count? 07:00.490 --> 07:03.730 How are we going to lower that minion count? 07:03.760 --> 07:04.330 Right. 07:04.330 --> 07:06.580 So that's a question we have to think about. 07:06.580 --> 07:13.840 But here's another question, and this is something that some developers feel a lot more strongly about 07:13.840 --> 07:14.560 than others. 07:14.560 --> 07:22.300 But if increment minion count can take a negative value and decrement the minion count, well that goes 07:22.300 --> 07:24.040 against the name, right? 07:24.040 --> 07:32.020 If we use this function to decrement the minion count by passing a negative value in this really grinds 07:32.020 --> 07:33.700 some developers gears. 07:33.790 --> 07:39.640 Some would say that increment minion count should only be able to increment the minion count and there 07:39.640 --> 07:44.800 should be a decrement minion count that should only be able to decrement the minion count. 07:44.890 --> 07:50.770 Now, if you were a mathematician, you would say that, well, you could add a negative value and that's 07:50.770 --> 07:52.330 the same as subtract. 07:52.330 --> 07:57.520 So increment by a negative value means subtract means decrement. 07:57.880 --> 08:06.700 Now, whatever philosophy you subscribe to here, by all means do what makes you feel is better. 08:06.700 --> 08:12.040 Here, make two functions, one for incrementing and one for decrementing if that's what you want to 08:12.040 --> 08:12.790 do. 08:12.790 --> 08:19.330 Or you could just say add to minion count and you can add a negative value and then it doesn't necessarily 08:19.330 --> 08:24.220 restrict you to incrementing or just have a setter set minion count. 08:24.250 --> 08:25.960 It's really up to you. 08:26.230 --> 08:31.780 I'm going to keep increment minion count and if I need to decrement it, I'm going to pass a negative 08:31.780 --> 08:32.950 value in there. 08:33.010 --> 08:40.270 I'm really sorry if that upsets you, but feel free to implement your naming conventions differently. 08:40.870 --> 08:46.180 Okay, so the first thing we should do is increment our minion count when we spawn a new minion. 08:46.180 --> 08:50.080 So let's launch the editor and make sure we're at least doing that. 08:52.070 --> 08:56.630 So we can go back and open up our ability. 08:56.780 --> 09:04.220 So we'll go to blueprints, ability system, enemy abilities and open up our summon ability. 09:04.220 --> 09:08.820 And every time we call Spawn actor, we should increment the minion count. 09:08.840 --> 09:12.050 So I'm going to go ahead and move these nodes forward. 09:12.650 --> 09:17.690 I'm not really needing my draw debug sphere anymore, so I'm going to remove that. 09:18.680 --> 09:24.050 And I'm just going to tidy this up real quick, like so. 09:24.200 --> 09:33.440 And just after spawning an actor, I'm going to right click and call increment minion count. 09:37.820 --> 09:38.780 For the target. 09:38.810 --> 09:42.260 We're getting the avatar actor from actor info. 09:43.170 --> 09:50.250 Passing that in and the amount is going to be one because we have now spawned a single minion. 09:51.800 --> 09:54.110 So we're incrementing the minion count. 09:54.140 --> 09:55.760 How do we decrement it? 09:55.790 --> 09:58.340 Well, we'll get to that in just a second. 09:58.340 --> 10:06.850 But first, I want to see if this is working by using my new BT attack task for the Elementalist. 10:06.860 --> 10:10.160 So I'm going to go not into my enemy blackboard. 10:10.160 --> 10:13.130 Actually, I don't know why my enemy blackboard was open. 10:13.130 --> 10:21.290 I want my behavior tree, but for the elementalist and instead of BT attack, I'm going to drag off 10:21.290 --> 10:29.360 and go to my tasks and get BT attack Elementalist instead and replace this attack with this one. 10:29.360 --> 10:35.540 Now we do need to change the combat target selector to target to follow. 10:37.230 --> 10:39.420 Just like our other attack here. 10:40.200 --> 10:48.150 We're going to change the node name to Elementalist attack and we're going to leave that minion spawn 10:48.150 --> 10:52.080 threshold at two and we're going to remove the old attack. 10:52.080 --> 10:54.440 So now we have an elementalist attack. 10:54.450 --> 11:00.690 We're going to replace that here and we're going to replace it here for the melee attack just in case 11:00.720 --> 11:05.340 our ranged elementalist finds its way into this one. 11:05.340 --> 11:12.990 So dragging off getting our attack elementalist here, removing the melee attack. 11:12.990 --> 11:20.040 And then this one is going to be combat target selector will be target to follow and we'll give the 11:20.040 --> 11:23.400 node name elementalist attack. 11:23.880 --> 11:29.250 So let's just really quickly see if we get the behavior we want. 11:29.280 --> 11:36.420 Now, what I expect is my shaman will first summon things because it's going to go into this task. 11:36.420 --> 11:41.050 It's going to check the minion spawn threshold and it's going to check the minion count, which will 11:41.050 --> 11:41.920 be zero. 11:41.920 --> 11:44.710 So it will first activate the summon ability. 11:44.710 --> 11:52.030 After that, it's going to have five minions, at which point it will then hit the false side of this 11:52.030 --> 11:54.430 branch and activate the attack tag. 11:54.430 --> 11:58.030 So we should get Firebolts after that, let's press play. 11:59.570 --> 12:01.220 And we don't see a summon. 12:02.500 --> 12:04.360 Let's find out why. 12:07.730 --> 12:09.950 I'm going to print my minion count. 12:11.360 --> 12:12.200 Here. 12:15.000 --> 12:16.770 And it's zero. 12:16.830 --> 12:17.690 Okay. 12:17.700 --> 12:26.880 As expected and zero is less than minion spawn threshold, which means we want to activate the ability 12:26.880 --> 12:28.020 with the summon tag. 12:28.020 --> 12:32.520 Oh, and of course we're activating abilities using our attack tag. 12:32.520 --> 12:35.520 We actually need to use the ability tag now. 12:35.520 --> 12:39.990 So that is why we saw the attack ability. 12:40.020 --> 12:42.780 Now we're going to activate with the ability tag. 12:42.780 --> 12:44.790 Now we should see that summon first. 12:44.970 --> 12:46.200 There it is. 12:47.580 --> 12:51.150 And we have our attack now. 12:51.360 --> 12:58.620 Interestingly, we got our minions spawned and I assume they were spawned over here for some reason. 12:58.650 --> 13:00.160 Let's go and find out why. 13:00.180 --> 13:01.950 We'll go to our summon ability. 13:02.740 --> 13:04.060 To spawn actor. 13:04.060 --> 13:06.310 And it looks like I broke something here. 13:06.340 --> 13:10.830 This should actually have our spawn location. 13:10.840 --> 13:15.910 We're going to spawn the actor at our chosen spawn location. 13:15.910 --> 13:16.500 Right? 13:16.510 --> 13:19.180 So we're going to get our spawn locations. 13:20.060 --> 13:21.560 We're going to get a copy. 13:23.680 --> 13:26.500 And we're getting it at our spawn location index. 13:27.180 --> 13:28.110 Right there. 13:29.200 --> 13:31.990 And we're raising it by 70 units. 13:33.980 --> 13:34.640 There we go. 13:34.640 --> 13:36.110 That's what we wanted to see. 13:36.350 --> 13:39.140 And after that, we get the fireball. 13:39.920 --> 13:42.050 Okay, so this is looking great. 13:42.080 --> 13:43.280 Now there's an issue. 13:43.310 --> 13:46.100 We're never decrementing that minion count. 13:46.100 --> 13:49.420 So I can kill some of these minions here. 13:49.430 --> 13:54.660 But if I do, that's not going to subtract one from the minion count. 13:54.680 --> 14:01.040 So really, we're never going to get more minions once I get down to one minion left, which is the 14:01.040 --> 14:02.180 behavior I want. 14:02.330 --> 14:07.970 So in the next video, we're going to work on how we can decrement that minion count when one of our 14:07.970 --> 14:09.030 minions dies. 14:09.050 --> 14:11.180 So great job and I'll see you soon.