WEBVTT 00:06.830 --> 00:08.060 Welcome back. 00:08.650 --> 00:10.510 So things are coming right along. 00:10.510 --> 00:12.550 We have our enemies approaching. 00:12.550 --> 00:20.320 We have our melee enemies attacking, but so far it just plays an attack montage, although we do have 00:20.350 --> 00:29.650 that location at the tip of the spear, as indicated by our debug red sphere, what I'd like to do is 00:29.650 --> 00:39.010 use that location and get all actors within the radius of that point, that spear point, so that we 00:39.010 --> 00:43.120 can do things to them like apply gameplay effects and so on. 00:43.120 --> 00:47.080 Now this is going to involve some kind of query. 00:47.110 --> 00:54.880 We need to see what actors exist within some sphere of a particular radius. 00:55.030 --> 01:03.040 Now finding all actors or players within a given sphere is quite useful. 01:03.040 --> 01:09.080 It's one of those types of things that you would add to a blueprint function library because because 01:09.080 --> 01:11.090 you could use it for multiple purposes. 01:11.090 --> 01:14.030 You could use it for what we want to use it for here. 01:14.030 --> 01:22.190 In our case, we'd like to say cause a damage gameplay effect to all actors inside of the sphere, but 01:22.190 --> 01:24.350 we could use it for a number of things. 01:24.350 --> 01:28.940 You could probably think of 4 or 5 different use cases for something like this. 01:28.940 --> 01:34.670 So we're going to make a nice static function to add to our function library for this. 01:34.700 --> 01:43.250 Now I'd like to have this function check to see if any actors within that radius are still alive, because 01:43.250 --> 01:48.140 I don't really care about any actors within the radius that have already died. 01:48.140 --> 01:52.370 Now we've already introduced the concept of death to our project. 01:52.610 --> 02:00.050 In fact, our combat interface has a die function and it'd be handy if we could have interface functions 02:00.050 --> 02:06.980 to check to see if we have died, to see if the thing that implements that interface has died. 02:07.220 --> 02:14.840 Now, another thing that I think would be extremely useful is if our combat interface could return the 02:14.840 --> 02:22.340 Avatar actor, the actor associated with the combat interface that implements it, basically its owner. 02:22.370 --> 02:24.440 So that would be nice. 02:24.440 --> 02:31.010 And we've seen that when we make these functions Blueprint Native event that we could execute the static 02:31.010 --> 02:35.660 function, the execute version of it without having to cast to the interface. 02:35.660 --> 02:41.300 We saw this in our projectile spell we had execute get combat socket location. 02:41.300 --> 02:44.720 This exists because we made that blueprint native event. 02:44.750 --> 02:52.220 We can do that same thing for functions on the combat interface to get whether our actor has died and 02:52.220 --> 02:56.090 to also get the actor itself an avatar, if you will. 02:56.090 --> 03:01.700 Now for that reason, I'd like to make two blueprint callable functions. 03:01.700 --> 03:07.910 One to get whether or not the player or character has died and one for getting the avatar. 03:08.000 --> 03:18.590 So the first one I'm going to get is a boolean called is Dead So Is Dead will be Blueprint Native event 03:18.590 --> 03:19.910 Blueprint Callable. 03:19.910 --> 03:26.480 Let's go ahead and mark it as such and the next one will return an A actor pointer and this is going 03:26.480 --> 03:29.120 to be called get Avatar. 03:30.930 --> 03:36.960 So get Avatar will also be Blueprint Native event Blueprint callable. 03:37.170 --> 03:43.340 Now these are simple getters, so there's really no reason that they can't be const functions. 03:43.350 --> 03:44.760 Let's go ahead and mark them both. 03:44.760 --> 03:45.450 Const. 03:49.500 --> 03:52.140 And we just need to override these. 03:52.140 --> 03:55.470 We can override them in the or a character base class. 03:55.470 --> 03:57.840 So let's go there and override them. 03:57.840 --> 04:01.620 Here we're going to have a virtual BOOL. 04:01.620 --> 04:07.320 Returning function is dead, but we have to override the implementation version and we're also going 04:07.320 --> 04:11.970 to have a virtual a actor returning function called Get Avatar. 04:12.000 --> 04:16.800 That's also the implementation version We must override. 04:16.830 --> 04:21.270 These, by the way, are functions belonging to the combat interface. 04:21.270 --> 04:28.440 So just like we did in our enemy class or an enemy where we have this combat interface, we could do 04:28.440 --> 04:31.410 the same thing in or a character base. 04:31.410 --> 04:37.110 We can say this is the combat interface and right here is the end of the combat interface. 04:37.110 --> 04:38.070 We could do that. 04:38.100 --> 04:41.550 That would allow us to put those functions there. 04:41.580 --> 04:43.320 These are all public, by the way. 04:43.320 --> 04:47.310 And here we have get hit, react montage. 04:47.340 --> 04:50.650 We have die and get player level. 04:50.650 --> 04:53.380 These are all functions belonging to this interface. 04:53.380 --> 05:00.310 We could move them into this comment and again, they're public so we could actually move these all 05:00.310 --> 05:02.980 up to the public section. 05:02.980 --> 05:08.440 So I'm just going to quickly do that, move these up to the public section like so, and if we missed 05:08.440 --> 05:10.300 any, we can move them in there later. 05:10.300 --> 05:13.000 But we do need to implement these two functions. 05:13.000 --> 05:19.990 So we're going to generate function definitions and what are we going to return for is dead and get 05:19.990 --> 05:20.530 Avatar. 05:20.530 --> 05:22.780 Well, get Avatar is the easiest one. 05:22.780 --> 05:24.670 It's going to return this. 05:25.030 --> 05:33.730 And in fact this can't be const as the function cannot convert from const A or a character base pointer 05:33.730 --> 05:35.590 to type a actor. 05:35.740 --> 05:43.690 So we'll go ahead and just remove const from this and from the declaration here and from combat interface. 05:45.080 --> 05:46.550 That'll take care of that. 05:47.060 --> 05:48.680 Now for is dead. 05:48.890 --> 05:51.200 Now we have a die function, don't we? 05:51.200 --> 06:00.770 And if we want is dead to return that status, we can have a variable for whether or not this particular 06:00.770 --> 06:02.720 character has died. 06:02.750 --> 06:06.020 So we can go ahead and just add that variable here. 06:06.050 --> 06:08.570 I'll go ahead and make it right here in the protected section. 06:08.610 --> 06:10.310 Bool, be dead. 06:11.440 --> 06:19.160 We'll set it to false by default and we have a handy is dead function that will return that. 06:19.190 --> 06:21.210 Let's go ahead and return that here. 06:21.230 --> 06:23.870 Return be dead. 06:24.140 --> 06:27.830 Now be dead is never set so we can always set that. 06:27.830 --> 06:31.590 We only really need to set it to true if the character dies. 06:31.610 --> 06:35.170 Now we don't have to make this a replicated variable. 06:35.180 --> 06:40.010 If we set it in multicast, handle death because then it will be set everywhere. 06:40.010 --> 06:41.540 Clients and server. 06:41.540 --> 06:43.070 So we can just set it here. 06:43.100 --> 06:44.970 Be dead equals. 06:44.970 --> 06:45.660 True. 06:46.400 --> 06:50.330 So now we have two nice blueprint native events. 06:50.370 --> 06:54.770 They're blueprint callable is dead and get Avatar. 06:55.860 --> 06:56.990 Let's just compile. 06:57.030 --> 07:00.030 Make sure we haven't done anything too reckless. 07:00.330 --> 07:07.200 And with a successful compile, we're ready to head over to our Blueprint function library, where we 07:07.200 --> 07:14.510 can make use of these functions and create a function for getting all live players within a radius. 07:14.520 --> 07:16.520 So let's go to that. 07:16.530 --> 07:25.080 I'm actually going to close all tabs at this point and go to public ability system or ability system 07:25.080 --> 07:26.640 library dot H. 07:26.670 --> 07:30.240 We're going to make a new static function to add to our library. 07:30.750 --> 07:34.890 So what exactly is this function going to return? 07:34.890 --> 07:36.290 What's it going to take? 07:36.300 --> 07:44.540 Well, a function to get all live players within a radius is clearly going to need a world context object. 07:44.550 --> 07:48.360 I'd also like to pass in an array of actors that we can fill out. 07:48.390 --> 07:51.510 So this will be a static void function. 07:52.800 --> 07:57.850 I'm going to call it get live players within radius. 07:58.550 --> 08:04.040 I'd like it to be blueprint callable, so I'm going to give it that new function macro right off the 08:04.040 --> 08:04.760 bat. 08:04.880 --> 08:12.200 And for category, I'm just going to call this category gameplay mechanics as I don't really have a 08:12.200 --> 08:13.790 better name for it. 08:14.240 --> 08:19.340 Now get live players within radius will take a world context object. 08:19.370 --> 08:21.470 We're definitely going to need that. 08:22.510 --> 08:27.970 I'm also going to want to fill in a t array of actor pointers, so we're going to pass that in by reference. 08:28.000 --> 08:32.350 T array of type A actor pointer. 08:33.490 --> 08:37.550 We're going to pass it in by reference and I'm going to call this out. 08:37.570 --> 08:40.660 Overlapping actors. 08:41.860 --> 08:46.840 Now, whenever doing something like this, we can always ignore some actors. 08:46.840 --> 08:50.590 We can provide a t array of actors that we can ignore. 08:50.770 --> 08:59.560 So I'm going to provide a const reference to a t array of actor pointers called actors to ignore. 08:59.590 --> 09:02.860 That way, if we do want to ignore any actors, we can. 09:02.920 --> 09:07.420 Now we're going to get all live players within a radius, so we're going to need that radius. 09:07.420 --> 09:15.700 So I'll pass in radius and we need all live players within radius of some location, right? 09:15.700 --> 09:21.400 So we're going to pass in a const vector reference called Sphere location. 09:22.390 --> 09:26.560 So we're getting all live players within some invisible sphere. 09:26.590 --> 09:35.270 We need that sphere location more specifically, it actually is a sphere origin, the center of some 09:35.300 --> 09:36.740 imaginary sphere. 09:37.220 --> 09:41.960 So now all that's left is to decide how to implement this function. 09:41.960 --> 09:44.330 Let's generate the definition for it. 09:44.990 --> 09:52.190 Get all live players within radius and let's decide how we're going to do this. 09:52.490 --> 10:00.110 So the way I'd like to do this is to perform some kind of query, some kind of check for a sphere in 10:00.110 --> 10:01.130 the world. 10:01.160 --> 10:05.630 And first of all, get all actors inside of that sphere. 10:05.870 --> 10:07.700 So how do we do that? 10:08.220 --> 10:14.790 Well, I know of some functions that exist in the engine, but a lot of people ask me when I just come 10:14.790 --> 10:17.910 up with this magic function that exists in the engine. 10:17.910 --> 10:19.260 How did you know that? 10:19.560 --> 10:21.210 How did you figure that out? 10:21.360 --> 10:27.390 So for something like this, if I just give you the function, I should tell you, Well, how did I 10:27.390 --> 10:28.200 figure that out? 10:28.200 --> 10:30.750 How do I already know that? 10:30.960 --> 10:37.110 Well, the first thing I do, if I don't already know, is I try to think what exists in the engine 10:37.110 --> 10:40.350 that I do know about that does something similar. 10:40.440 --> 10:44.910 Now, I personally already know about a couple of things in the engine. 10:44.910 --> 10:49.260 So if I say, Well, I know about this function and you didn't know about that. 10:49.260 --> 10:51.900 Well, yes, that's something I knew that you didn't. 10:51.900 --> 10:54.030 But that comes with experience. 10:54.270 --> 10:59.460 So the more experience you get, the more things you will do, the more functions, you know, that 10:59.460 --> 11:00.630 exist in the engine. 11:00.630 --> 11:04.950 So, you know, with practice, you start to gain that kind of knowledge. 11:04.950 --> 11:13.000 But one of the things that I know exists in the engine is a nice function for applying radial damage 11:13.000 --> 11:14.350 with a fall off. 11:14.440 --> 11:20.770 You see, if you want to apply radial damage with a fall off in Unreal Engine, that's clearly going 11:20.770 --> 11:28.180 to involve seeing what actors are nearby and applying damage to each of those according to their distance 11:28.180 --> 11:31.420 from some origin, some sphere origin. 11:31.420 --> 11:38.470 So it would make sense that a function for applying radial damage with a fall off would query some kind 11:38.470 --> 11:41.870 of sphere to see what actors are overlapping. 11:41.890 --> 11:46.030 Now in writer I can hit shift twice and I can search. 11:46.030 --> 11:51.910 In Visual Studio it's control shift F where I could search the whole solution and I'm going to search 11:51.910 --> 11:56.140 for apply radial damage. 11:56.680 --> 11:58.150 With fall off. 11:59.830 --> 12:02.080 And I'll see the gameplay statics pops up. 12:02.080 --> 12:04.360 First thing, I'm going to double click on that. 12:04.810 --> 12:07.900 And here we have apply radial damage with falloff. 12:07.900 --> 12:15.040 So here's an example of a function that's already doing, at least in part, some of what we want to 12:15.040 --> 12:15.970 do, right? 12:16.000 --> 12:19.660 Let's look through this function line by line and see what it's doing. 12:19.960 --> 12:24.940 First, it's creating a struct of something called F collision query params. 12:24.940 --> 12:31.240 Now it's calling it sphere params interesting, and it's taking in something called scene query. 12:31.240 --> 12:33.130 Stat looks like a macro, right? 12:33.130 --> 12:40.870 And it says in stat id along with a boolean called Trace complex, which it's set to false. 12:40.870 --> 12:47.560 And then this damage causer looks like it's an actor, so sphere params might be something we want to 12:47.560 --> 12:48.280 create. 12:48.310 --> 12:49.450 Now check this out. 12:49.450 --> 12:57.040 Sphere params has add ignored actors taking in a const array reference called in ignore actors. 12:57.040 --> 13:01.130 So we have an array of actors we'd like to ignore. 13:01.130 --> 13:03.920 So that's a nice function to know about as well. 13:04.600 --> 13:12.160 Now the next line says query scene to see what we hit and it has a t array of something called F overlap 13:12.160 --> 13:12.940 result. 13:13.610 --> 13:16.420 Sounds kind of like F hit result, right? 13:16.420 --> 13:18.070 It's called overlaps. 13:18.070 --> 13:26.050 And this function gets the world with get world from context object and from that world it calls overlap 13:26.050 --> 13:28.090 multi by object type. 13:28.180 --> 13:34.720 Now what this does is it passes in that overlaps that t array of overlap results. 13:34.750 --> 13:39.610 It also takes a position looks like origin is passed in here. 13:39.790 --> 13:47.920 It takes a rotation in the form of a quaternion and also an f collision object query params. 13:47.920 --> 13:50.110 And what's being passed in here? 13:50.110 --> 13:57.250 Well, it looks like it's being created right here in f collision object query params which seems to 13:57.250 --> 14:06.800 have a constructor that takes in this f collision object query params init type all dynamic objects. 14:06.800 --> 14:07.850 Interesting. 14:07.850 --> 14:12.200 Now after that input it takes an f collision shape. 14:12.230 --> 14:19.910 So there's this f collision shape type and it looks like it has a static function make sphere which 14:19.910 --> 14:21.470 takes a radius. 14:21.650 --> 14:25.430 So that's how we can specify that this function overlap. 14:25.430 --> 14:33.350 Multi by object type can create some invisible sphere and check to see if any actors overlap with it. 14:33.350 --> 14:41.240 And then that last input is an f collision query params for which sphere params is passed in. 14:41.270 --> 14:44.480 That's that sphere params that was created here. 14:44.480 --> 14:52.100 So really this overlap multi by object type is performing most of the work here with a few parameters 14:52.100 --> 14:53.120 that are set. 14:53.570 --> 14:56.660 Now that's pretty much all we're interested in here. 14:56.660 --> 15:02.510 The rest of this stuff appears to be related to actually causing damage. 15:02.600 --> 15:05.090 All that we really cared about was this right? 15:05.090 --> 15:08.270 We wanted to overlap with stuff. 15:08.270 --> 15:15.680 So now that we've seen an example of how to get all overlapping actors in some kind of a radius, we 15:15.680 --> 15:19.310 can do something similar in our static function library. 15:19.310 --> 15:21.680 So let's think about how to do that. 15:21.710 --> 15:25.610 Now I'm going to keep gameplay statics open so we can use it as a reference. 15:25.640 --> 15:29.390 The first thing it does is creates an f collision query params. 15:29.600 --> 15:34.310 Now the most important thing that I see here is be trace complex. 15:34.310 --> 15:36.650 We don't want to trace against complex collision. 15:36.650 --> 15:37.850 I rarely do. 15:37.970 --> 15:43.730 I want to trace against simple collision things like the physics asset and what have you. 15:43.880 --> 15:51.530 Now it is taking in a damage causer actor for this collision query params constructor, but I suspect 15:51.530 --> 15:57.890 that there are multiple constructors for this collision query params there usually are for most types 15:57.890 --> 16:03.380 in the engine, so let's see what we can get away with creating our own collision query params called 16:03.380 --> 16:04.460 sphere params. 16:04.550 --> 16:11.150 So I'm going to make an f collision query params called sphere params. 16:11.480 --> 16:18.230 Now if I just hit semicolon I see that well look, it has a default constructor. 16:18.230 --> 16:24.830 I don't have to really pass anything into it, but if I right click on this type and I go to it. 16:25.210 --> 16:28.180 Then I see that it has a few different things. 16:28.300 --> 16:30.850 It has a number of variables. 16:30.940 --> 16:36.610 And if we scroll down enough, we can see that it has a constructor. 16:36.610 --> 16:41.830 It actually has a constructor that takes a number of inputs, but they all have default values. 16:41.830 --> 16:44.350 So we can get away with not passing any in. 16:44.380 --> 16:46.060 That's what's happening here. 16:46.090 --> 16:48.340 Now what do we care about? 16:48.370 --> 16:53.830 Well, we do want to trace against only simple collision, but that's already set there. 16:53.950 --> 16:55.780 We have a mobility type. 16:55.780 --> 16:56.890 What does that do? 16:56.920 --> 16:59.500 Well, it's an E query mobility type. 16:59.500 --> 17:06.880 And if we're really interested in that, we can go to the definition of that and see that we have any 17:06.880 --> 17:08.530 static and dynamic. 17:08.530 --> 17:11.950 Static says any shape that's considered static by physics. 17:11.980 --> 17:13.150 Static mobility. 17:13.150 --> 17:20.710 So this is actually an old comment that dates back to the time when Unreal Engine used physics as its 17:20.710 --> 17:21.760 physics engine. 17:21.790 --> 17:26.330 Unreal Engine now uses chaos as its physics engine, so this is interesting. 17:26.330 --> 17:29.870 It's one of those relics of code that was never updated. 17:29.870 --> 17:39.410 But nevertheless, for any objects that are simulating physics, if they're static or dynamic, we can 17:39.410 --> 17:45.560 only trace for those kinds of objects based on their mobility, or we can trace for any. 17:45.590 --> 17:45.920 Right. 17:45.950 --> 17:47.600 So that's interesting. 17:47.600 --> 17:50.270 We can set that mobility type. 17:50.660 --> 17:54.590 Okay, back to our collision query params. 17:54.620 --> 18:01.310 It's in this same header file so I can search for f collision query params and go back down to this 18:01.310 --> 18:02.360 constructor here. 18:02.360 --> 18:04.340 So we have mobility type. 18:04.340 --> 18:06.440 We also have a trace tag. 18:06.470 --> 18:11.990 It says tag used to provide extra information or filtering for debugging of the trace. 18:11.990 --> 18:13.940 I'm not too concerned with that. 18:13.970 --> 18:17.870 We have find initial overlaps that's set to true by default. 18:17.870 --> 18:21.680 It says whether we want to find out initial overlap or not. 18:21.710 --> 18:23.480 If true, we'll return. 18:23.480 --> 18:26.840 If this was an initial overlap, that's something we do want. 18:26.870 --> 18:32.870 True because we're going to do the query and if anything was already overlapping, we want that. 18:33.020 --> 18:40.850 Now there's a number of other things, and I think the most important thing here is tracing complex 18:40.850 --> 18:42.530 and the mobility type. 18:42.530 --> 18:45.080 I'm not really too concerned with any of this other stuff. 18:45.080 --> 18:48.730 So what I'm going to do is set these two properties. 18:48.750 --> 18:51.710 It looks like they're the first two, so I could pass in a false. 18:51.710 --> 18:55.850 And let's just say I only want dynamic objects. 18:55.850 --> 18:56.360 Really. 18:56.360 --> 18:58.370 I could just leave it at any if I want to. 18:58.400 --> 19:03.950 We're going to check those objects anyway, make sure that they implement our interface and that they're 19:03.950 --> 19:04.750 alive. 19:04.760 --> 19:07.280 So yeah, really, it doesn't matter. 19:07.280 --> 19:12.380 We don't have to set any of these, so I'm just going to leave it at sphere params. 19:12.380 --> 19:16.370 It has its settings set to my liking already. 19:16.400 --> 19:21.410 Now, I may have spoken too soon because we do have our actors to ignore, don't we? 19:21.440 --> 19:24.170 So that's really the only thing that I'd like to set. 19:24.170 --> 19:31.550 I'm going to take my sphere params and call that function, add ignored actors and pass in actors to 19:31.550 --> 19:32.660 ignore for that. 19:34.900 --> 19:37.210 And after that I have my sphere params. 19:37.240 --> 19:40.900 All right, let's go back to gameplay statics and see the next thing we did. 19:40.900 --> 19:43.960 So after add ignored actors. 19:43.990 --> 19:52.420 Next there was a t array of f overlap results and we then called overlap multi by object type on the 19:52.420 --> 19:53.380 world. 19:53.410 --> 19:56.320 So that's what we're going to want to do. 19:56.320 --> 20:05.080 So I'm just going to copy the line declaring the t array and come back to my function and paste it. 20:05.080 --> 20:09.160 So I have this overlaps and I'm going to want to get the world. 20:09.160 --> 20:15.820 So I'm going to have an if statement and make a const New World Pointer and I'm going to call it World 20:15.820 --> 20:18.790 and set it equal to what was the function. 20:18.790 --> 20:19.900 Let's go look. 20:19.900 --> 20:21.550 It's getting it from engine. 20:21.550 --> 20:25.270 It's saying G engine, get world from context object. 20:25.300 --> 20:31.030 Now, this function requires a world context object as well as an E get world error mode. 20:31.030 --> 20:36.290 So if it fails to get the world this s error mode determines what to do. 20:36.290 --> 20:39.440 In response to that, it says log and return null. 20:39.470 --> 20:46.280 That sounds to me like it's going to log something, an error perhaps, and return a null pointer. 20:46.310 --> 20:47.720 That's the behavior I'd like. 20:47.720 --> 20:52.760 So I'm going to copy the function call, come back to my function, call it there. 20:52.760 --> 20:56.980 And if we make it inside this if statement, we have the world. 20:56.990 --> 21:03.050 Now, once the world has been acquired, we have overlap multi by object type. 21:03.050 --> 21:07.490 With all these parameters, let's just copy the whole line. 21:08.440 --> 21:10.580 And we'll call that function here. 21:10.600 --> 21:13.960 Now, of course, we're going to need to change some things, right? 21:13.990 --> 21:15.850 Let's see what we need to change. 21:15.940 --> 21:19.390 The first input is the t array of overlap results. 21:19.390 --> 21:21.460 We can pass that in now. 21:21.460 --> 21:24.150 The next input is origin. 21:24.160 --> 21:28.360 That's going to be our sphere origin, so we can go ahead and pass that in. 21:28.510 --> 21:30.160 Now, next is a rotation. 21:30.160 --> 21:37.150 I don't care about a rotation for a sphere, so we're going to leave that at identity for the F collision 21:37.150 --> 21:38.560 object query params. 21:38.560 --> 21:43.540 I think all dynamic objects is fine for the f collision shape. 21:43.540 --> 21:49.810 We're going to make a sphere, but it needs a radius and our function has a radius input. 21:49.810 --> 21:51.880 So we're going to pass in the radius. 21:51.880 --> 21:59.710 And finally we get our sphere params pass that in and after this our array should have some overlaps. 21:59.950 --> 22:00.880 All right. 22:01.630 --> 22:07.650 Now, what I really like to do is loop over this array so I can make a for loop. 22:07.660 --> 22:11.050 Now, what are these items in overlaps? 22:11.050 --> 22:14.140 Well, they're overlap results, right? 22:14.140 --> 22:17.290 So I'm going to use overlap result. 22:17.380 --> 22:19.540 I'm going to use a reference for it. 22:19.540 --> 22:21.850 I'm going to call it overlap result. 22:22.300 --> 22:23.650 I'll just call it overlap. 22:24.310 --> 22:26.830 And we're going to loop through the overlaps array. 22:27.670 --> 22:29.710 And for each of these, what am I going to do? 22:29.710 --> 22:30.970 Well, overlap. 22:30.970 --> 22:36.640 If I type overlap dot, then we have a number of functions including get actor. 22:36.670 --> 22:43.210 That's really the only one I care about because this actor is what I'd like to check for one to see 22:43.210 --> 22:46.000 if it implements my combat interface to. 22:46.000 --> 22:48.550 I want to see if it is dead. 22:48.550 --> 22:56.680 And three, I want to add that actor to my out overlapping actors array, and then my function has done 22:56.680 --> 22:57.700 its job. 22:57.880 --> 23:03.890 So what I'm going to do is first check to see if the actor implements my combat interface. 23:04.040 --> 23:08.210 Now, one way we can do this is we can call implements. 23:08.270 --> 23:14.000 Implements is a template function that requires the type of the interface you're interested in. 23:14.030 --> 23:20.870 Now, unlike when we say cast the actor to our interface, we don't use the I combat interface. 23:20.870 --> 23:24.650 We use the you combat interface instead. 23:25.040 --> 23:32.480 So this is going to return a Boolean whether or not this actor implements the interface so I can make 23:32.480 --> 23:39.350 a local const bull called implements Combat interface, for example. 23:39.350 --> 23:43.940 And it'll be true if the actor does in fact implement it. 23:43.970 --> 23:48.770 Now, in addition to that, I want to know if the actor's dead, so I'm going to make another const 23:48.770 --> 23:55.850 bool called is I'll make it is alive and I'll set it to true if the actor is dead. 23:55.850 --> 24:02.930 Now for that I can use the static function on I combat interface, which is the execute version of is 24:02.930 --> 24:03.470 dead. 24:03.500 --> 24:09.440 But this of course requires the object that implements that interface that's going to be overlapped. 24:09.470 --> 24:10.520 Get actor. 24:10.940 --> 24:18.020 So now I know both whether or not the interface is implemented and if that actor is alive and I can 24:18.020 --> 24:23.420 check these conditions, I'm going to check first implements combat interface, but I'm also going to 24:23.420 --> 24:25.820 check with an and is alive. 24:25.820 --> 24:31.190 And I almost made a logical error here because this is checking is dead. 24:31.220 --> 24:36.830 We want a negation operator here because if it's not dead, it's alive. 24:36.950 --> 24:41.390 So we only want to do anything if it's, first of all, implementing the interface. 24:41.390 --> 24:43.820 And second of all, not dead. 24:43.850 --> 24:46.160 Now, at this point, it's pretty simple. 24:46.160 --> 24:52.280 What we need to do, we need to add that actor to our out overlapping actors. 24:52.280 --> 25:00.500 So I'm going to take out overlapping actors and I'm going to use Add Unique so we don't get any duplications. 25:00.500 --> 25:10.400 And I can simply use overlap dot get actor or if I want to, I could take that interface I combat interface 25:10.400 --> 25:20.330 and call execute get Avatar as we created that as a nice function to get the avatar we can pass in overlap 25:20.330 --> 25:21.410 dot get actor. 25:21.410 --> 25:28.160 I know it's a little bit of a roundabout way if we already have the actor well we have it so you know 25:28.160 --> 25:31.700 you don't really have to call this execute get avatar. 25:31.700 --> 25:34.370 We can just pass in overlap get actor. 25:34.370 --> 25:43.460 But either way, we should now have our out overlapping actors filled in with all live avatars controlled 25:43.460 --> 25:45.320 by players or AI. 25:45.350 --> 25:53.810 So with that we can go ahead and play, test this and see if we actually get all overlapping actors 25:53.810 --> 25:55.970 and we can do something to them. 25:57.140 --> 25:58.790 Okay, I'm going to click open. 25:58.820 --> 26:00.530 Go back to my game. 26:00.590 --> 26:02.180 Melee attack. 26:02.270 --> 26:07.340 And I'm going to see if I can call my new static function. 26:07.640 --> 26:10.370 Get live players within radius. 26:10.550 --> 26:11.960 Here it is. 26:11.990 --> 26:13.730 Now we need a sphere origin. 26:13.730 --> 26:16.220 That's going to be the combat socket location. 26:16.250 --> 26:17.900 We need a radius. 26:17.900 --> 26:20.540 I'm just going to pass in 45 for now. 26:20.570 --> 26:22.450 We need actors to ignore. 26:22.460 --> 26:29.410 I'm going to get the avatar actor of this melee attack and hook it straight into actors to ignore. 26:29.420 --> 26:31.190 That's going to create an array. 26:31.280 --> 26:39.890 We need a world context object we can pass in self or we can pass in the Avatar actor directly. 26:39.920 --> 26:41.690 Either way is fine. 26:41.690 --> 26:45.920 And what are we going to do with our out overlapping actors? 26:45.950 --> 26:49.610 Well, we could for now just draw debug spheres. 26:49.610 --> 26:56.040 I know debug spheres are less exciting than say causing real damage, but we'll get to that. 26:56.060 --> 27:03.530 So let's go ahead and draw debug spheres for each of our overlapping actors. 27:03.550 --> 27:08.460 In fact, we could loop through these with a for each loop. 27:11.660 --> 27:14.900 And for the loop body we could draw the debug sphere. 27:16.120 --> 27:17.590 Using the array element. 27:17.590 --> 27:18.790 This is an actor. 27:18.820 --> 27:24.670 We'll get actor location and we'll just draw a debug sphere at the actor's location. 27:24.820 --> 27:27.220 This will be a different color. 27:27.220 --> 27:33.430 Let's make it greenish, greenish blue and I'll go ahead and draw this smaller. 27:33.430 --> 27:36.370 We'll make it radius 15. 27:36.670 --> 27:37.420 Okay. 27:37.510 --> 27:45.010 And we also want to end the ability not after drawing the first debug sphere, we'll only end the ability 27:45.010 --> 27:46.600 when we complete the loop. 27:46.720 --> 27:50.260 But really this for each loop is just for debug purposes. 27:50.260 --> 27:53.890 We only care that we're getting any live players within the radius. 27:53.890 --> 27:56.440 So let's see if we're doing that. 27:57.730 --> 27:58.670 Save all. 27:58.690 --> 27:59.740 Press play. 28:00.890 --> 28:02.510 Let's see if we get hit. 28:02.510 --> 28:03.530 And there we go. 28:04.290 --> 28:10.380 So we don't want to see that sphere at the tip of the spear anymore necessarily. 28:10.410 --> 28:17.180 We just want to see the sphere at the actor's location, which is the center of aura. 28:18.580 --> 28:19.540 There we go. 28:20.310 --> 28:20.720 Okay. 28:20.730 --> 28:23.280 Now we got a exception here. 28:23.400 --> 28:28.060 And I suspect that I know what it's from, but let's take a look. 28:28.080 --> 28:30.240 We're failing this check here. 28:30.270 --> 28:36.210 That's checking implements, interface passing in you combat interface, static class. 28:36.420 --> 28:44.880 So we see that right here after calling execute is dead and passing in an object here called AU. 28:44.910 --> 28:48.090 That AU has get class called. 28:48.090 --> 28:54.720 And from that class we're calling implements interface with you combat interface static class. 28:54.990 --> 28:58.890 We see that AU is BP test actor. 28:59.340 --> 29:01.530 So that's a problem. 29:01.560 --> 29:09.150 BP test actor does not implement the interface and because test actor does not implement the interface, 29:09.150 --> 29:17.160 then this check fails because our test actor after calling implements interface will return zero here. 29:17.160 --> 29:25.240 So execute is dead is not going to allow us to even check anything that doesn't implement the interface. 29:25.420 --> 29:32.650 Now that's a pretty easy fix we don't even want to try to execute is dead if we don't implement the 29:32.650 --> 29:33.650 interface. 29:33.670 --> 29:41.200 So one easy thing we could do is check implements interface first and only continue. 29:41.230 --> 29:48.370 We could make an if statement here and then we'll never try to execute is dead unless the actor implements 29:48.370 --> 29:49.090 the interface. 29:49.090 --> 29:50.140 That's one. 29:50.140 --> 29:55.080 Or we can make this more compact and just check overlap. 29:55.390 --> 30:04.030 Get actor implements first in our if statement here and if this first part of the if statement fails, 30:04.030 --> 30:10.750 then the and will never check the second one and that second one can be not execute is dead. 30:10.870 --> 30:12.220 We can replace that. 30:12.220 --> 30:15.280 And then we don't need these two temporary booleans. 30:15.700 --> 30:21.490 We'll first check and make sure that we implement the interface and then check to make sure we're dead. 30:21.490 --> 30:22.150 But we don't. 30:22.150 --> 30:28.450 Check is dead unless we make it pass this first check and then we'll never get that exception. 30:28.450 --> 30:33.480 So with that, let's go ahead and hit stop and we'll debug this. 30:33.490 --> 30:35.320 This should take care of that. 30:35.320 --> 30:37.180 Just a logic error there. 30:38.190 --> 30:39.030 Okay. 30:39.300 --> 30:41.550 I'm going to go ahead and open up my. 30:42.360 --> 30:44.100 Melee attack again. 30:44.100 --> 30:46.380 Looks like everything is still there. 30:47.090 --> 30:48.920 I'm going to go ahead and press play. 30:49.340 --> 30:53.360 We're going to get close to the effect actor that was causing the problem. 30:53.360 --> 30:57.410 And now the problem is no more. 31:00.010 --> 31:02.680 Yeah, and we're definitely overlapping with this effect. 31:02.680 --> 31:06.550 Actor And no problems are occurring. 31:06.910 --> 31:08.050 Perfect. 31:08.350 --> 31:11.940 Now, this time we got this other enemy, right? 31:11.950 --> 31:14.440 It was overlapping in that radius too. 31:14.470 --> 31:16.630 Let's see if we can make it happen again. 31:17.140 --> 31:18.160 There we go. 31:18.160 --> 31:21.850 We got two spheres, one for me and one for the other enemy. 31:21.970 --> 31:30.100 So if we wanted to only affect Aura and not the enemies, or if it's aura doing it, we only want to 31:30.100 --> 31:34.040 affect the enemies and not aura and other friendly players. 31:34.060 --> 31:39.940 Well, we could also check those tags that we gave our aura character and our enemy. 31:39.940 --> 31:42.370 We have tags, aura and enemy. 31:42.370 --> 31:44.590 That's something that we could look into. 31:44.620 --> 31:47.330 For now, I think this is working just fine. 31:47.350 --> 31:50.140 We are getting all live players within Radius. 31:50.170 --> 31:57.820 We're now ready to start doing cool things like damage and parameterizing some of these values in melee 31:57.850 --> 32:01.400 attacks so we can reuse it with a bunch of different types of enemies. 32:01.400 --> 32:04.400 So things are starting to look great. 32:04.550 --> 32:07.670 Excellent job and I'll see you in the next video.