WEBVTT 00:07.170 --> 00:08.370 Welcome back. 00:08.520 --> 00:16.380 Now I'd like a way to access our widget controllers for our project, At least those that should only 00:16.380 --> 00:19.260 exist as a single instance. 00:19.260 --> 00:22.170 There shouldn't be copies constructed all over the place. 00:22.170 --> 00:27.440 That would be our overlay and our attribute menu widget controllers. 00:27.450 --> 00:35.130 If we go into attribute menu and open up our attribute menu, then I'd like to be able to go into the 00:35.130 --> 00:44.670 attribute menu, into the event graph, right click and type something like get attribute menu, widget 00:44.670 --> 00:46.620 controller or something like that. 00:46.620 --> 00:49.530 And I'd love if it popped up right here. 00:49.710 --> 00:55.350 A nice little function with this name that returns the attribute menu widget controller. 00:55.350 --> 01:02.670 And then as soon as this attribute menu gets constructed, say in event construct, for example, I'd 01:02.670 --> 01:05.250 like it to set its own widget controller. 01:05.370 --> 01:08.860 I'd like this because I don't really want to have to do that. 01:08.860 --> 01:10.620 From the overlay class. 01:10.630 --> 01:18.910 You see, the overlay overlay could set the widget controller as soon as we click the attribute menu 01:18.910 --> 01:24.970 button because we're constructing the attribute menu widget here, we could take it and say set widget 01:24.970 --> 01:25.570 controller. 01:25.570 --> 01:31.090 But I really would like if the attribute menu could handle that itself as soon as we create it. 01:31.120 --> 01:36.340 Now, we can't really do that with some of the widgets in the overlay, such as our Health and Mana 01:36.370 --> 01:43.690 globes, because timing is important here and the widget controller for the overlay is set at a specific 01:43.720 --> 01:47.860 time and the Health and Mana Globes share that widget controller. 01:47.860 --> 01:50.560 So we do want to time this correctly. 01:50.560 --> 01:57.730 We want to make sure that our overlay widget controller is set before our Globes widget controllers 01:57.730 --> 01:58.450 are set. 01:58.450 --> 02:02.500 So in this case, the overlay can set those widget controllers. 02:02.500 --> 02:08.650 But for the attribute menu, as soon as we click that button, we're constructing a new attribute menu. 02:08.650 --> 02:14.290 I'd like the attribute menu to handle setting its own widget controller, especially because it's a 02:14.290 --> 02:16.960 different widget controller than the overlay has. 02:16.960 --> 02:23.410 The overlay uses the overlay widget controller class Attribute menu is now going to use its own attribute 02:23.410 --> 02:25.840 menu widget controller class. 02:25.840 --> 02:31.230 So for that reason I'd like to create a blueprint function library. 02:31.240 --> 02:33.100 What's a blueprint function library? 02:33.100 --> 02:39.010 Well, if you right click in the event graph and type get ability system component for example. 02:40.120 --> 02:42.520 And select that and hover over it. 02:42.520 --> 02:46.440 You see that the target is Ability System Blueprint Library. 02:46.450 --> 02:48.940 That's a blueprint function library. 02:49.090 --> 02:56.740 It's a bunch of static functions, usually static, that are declared in a class such as the ability 02:56.740 --> 03:03.550 system, blueprint, library, class and usually expose to blueprint in the form of these blueprint 03:03.580 --> 03:04.060 nodes. 03:04.060 --> 03:10.330 This is a blueprint, pure function, and we've already looked into the insides of this function and 03:10.330 --> 03:13.240 seen how it accesses ability system components. 03:13.240 --> 03:21.310 When it's given an actor, we're going to make our own ability system Blueprint library for our project. 03:21.310 --> 03:22.300 So I'd like to do that. 03:22.300 --> 03:30.070 Now let's go into C plus plus classes ora public and we need to decide where we'd like this function 03:30.070 --> 03:30.970 library. 03:31.060 --> 03:37.540 And really it could go anywhere if we're going to call this something with ability system in the name, 03:37.540 --> 03:42.950 perhaps we should stick it in the ability system folder and we could just put it right here next to 03:42.950 --> 03:46.550 the ability system component and attribute set classes. 03:46.550 --> 03:49.070 So I'd like to do that. 03:49.070 --> 03:50.330 Let's make a new class. 03:50.330 --> 03:55.010 I'm going to right click new C plus plus class, choose all classes. 03:55.010 --> 04:01.520 And now we need to ask ourselves what is the C plus plus class for a blueprint function library. 04:01.520 --> 04:07.670 Well, typing in blueprint function library is a great start and there it is. 04:07.700 --> 04:10.100 Blueprint function Library. 04:10.130 --> 04:17.000 Let's create this and I'd like to call this class aura ability system. 04:17.650 --> 04:18.740 Library. 04:18.760 --> 04:24.160 So we have our own ability system library called aura ability system library. 04:24.160 --> 04:29.020 We could call it aura ability system, blueprint, library like that. 04:29.020 --> 04:34.990 But then again, no, we can't because the class creation wizard here is telling us we can't go above 04:34.990 --> 04:35.980 32 characters. 04:35.980 --> 04:39.610 So aura ability system library it is. 04:39.640 --> 04:43.450 Let's create the class and close the editor. 04:43.630 --> 04:51.730 Go ahead and save everything there and we should get our new ability system Blueprint Library class. 04:51.730 --> 04:53.110 Why don't we open it up first? 04:53.110 --> 04:59.670 I'm going to close everything else, close all tabs and open up the CPP and open up the dot h. 04:59.680 --> 05:01.150 And here we have it. 05:01.180 --> 05:04.750 So now we have a blueprint function library. 05:04.780 --> 05:06.010 Pretty cool. 05:06.040 --> 05:14.740 Now I'm going to add a public section and the first thing I'm going to do is add a getter for the widget 05:14.740 --> 05:21.050 controller, the overlay widget controller that already exists, just so we can test out our new function 05:21.050 --> 05:24.290 library and see if it works in Blueprint. 05:24.380 --> 05:29.510 Now, with Blueprint function libraries, we usually make these static functions. 05:29.510 --> 05:35.360 In fact, we always make them static functions because we don't plan on creating a instance of this 05:35.360 --> 05:35.990 class. 05:35.990 --> 05:38.990 We just plan on calling it static functions. 05:38.990 --> 05:47.660 So we make a static function and this function is going to return the you overlay widget controller 05:47.660 --> 05:48.260 type. 05:48.260 --> 05:54.050 Now it's asking if we want to include or forward declare, we're going to forward declare because we 05:54.050 --> 06:01.160 just need a function declaration here and we're going to call this get overlay widget controller. 06:02.240 --> 06:03.500 Now here's the thing. 06:03.500 --> 06:09.980 This is a static function and if we're going to trace our way all the way up to the HUD, somehow we 06:09.980 --> 06:14.540 need to trace up to the HUD using an object that exists. 06:14.540 --> 06:19.670 But a static function cannot access any objects that exist in the world. 06:19.670 --> 06:19.970 Why? 06:20.000 --> 06:26.780 Because the class itself that the static function belongs to, may not exist in the world. 06:26.810 --> 06:33.500 The static function can be called directly, and this is the reason why many function libraries in the 06:33.500 --> 06:36.800 engine require a world context object. 06:36.800 --> 06:44.600 It needs a reference that it can use to trace its way up somehow, some way to something in the world 06:44.600 --> 06:46.100 that we want to affect. 06:46.340 --> 06:53.600 So our get overlay widget controller class needs a world context object, some kind of object that we 06:53.600 --> 06:57.230 can use to have context for the world that we're in. 06:57.530 --> 07:04.430 This is going to be a const uobject pointer called World Context Object. 07:05.910 --> 07:08.340 So we have a static function declaration. 07:08.340 --> 07:09.080 Great. 07:09.090 --> 07:12.060 But I'd like this to be exposed to blueprint. 07:12.060 --> 07:13.560 It'll be a new function. 07:14.700 --> 07:17.970 And this can be blueprint pure. 07:18.990 --> 07:22.930 It doesn't need an execution pin or anything like that. 07:22.950 --> 07:27.870 It's just going to perform some kind of operation and return a result. 07:28.200 --> 07:30.450 And we'll give it a category as well. 07:30.450 --> 07:41.280 And the category can be I'll have aura, ability, system, library and a subcategory of widget controller. 07:41.550 --> 07:43.320 So that looks nice and neat. 07:43.530 --> 07:45.810 So we'll generate the definition. 07:45.810 --> 07:52.920 And here we need to somehow, someway get the widget controller and return it to the caller. 07:52.950 --> 07:54.240 So how do we do that? 07:54.240 --> 07:57.390 Well, we need the player controller. 07:57.390 --> 07:58.500 So here's the thing. 07:58.500 --> 08:02.280 We're planning on calling this from a widget most likely. 08:02.280 --> 08:06.360 I don't really see any other reason to call this function. 08:06.360 --> 08:08.450 Widgets need widget controllers. 08:08.460 --> 08:15.610 So if we're calling this from within a widget, we're calling it from the perspective of a local player, 08:15.640 --> 08:23.200 a widget will only exist for the local player and we'll want the player controller associated with that 08:23.200 --> 08:25.390 game instance with that session. 08:25.390 --> 08:28.630 In other words, we can get the first player controller. 08:29.080 --> 08:34.270 So what I'm going to do is call the gameplay statics function you gameplay statics. 08:36.080 --> 08:37.550 Get player controller. 08:39.560 --> 08:46.670 And of course we need to include the gameplay statics header file if we want to call this function that's 08:46.670 --> 08:47.630 in kismet. 08:47.660 --> 08:51.350 So kismet slash gameplay statics dot H. 08:52.070 --> 08:54.580 And what does this function require? 08:54.590 --> 08:58.070 Well, it requires a world context object. 08:58.100 --> 09:04.340 We just happen to have one because we made this a requirement to be passed in when we call the function 09:04.340 --> 09:08.170 and get player controller needs an index and we're going to use zero. 09:08.180 --> 09:15.590 So now that we have a player controller, we're going to store it, a player controller, we'll call 09:15.590 --> 09:22.970 it PC for player controller, and we'll just check to make sure that this is not a null pointer. 09:23.750 --> 09:27.350 And from the player controller, we can always access the HUD. 09:27.350 --> 09:33.050 So we'll do this if check variable declaration trick again, we'll say if and in the if statement we'll 09:33.050 --> 09:36.620 say A or a HUD we're going to cast to or a HUD. 09:36.620 --> 09:46.040 So we're going to say HUD equals cast to a or a HUD because we want that class and we're going to use 09:46.070 --> 09:50.420 PC get HUD because the player controller can always get the HUD. 09:50.600 --> 09:57.300 And we need to alt enter a writer trick or just include or a HUD. 09:57.420 --> 09:59.910 And now we have access to the or a HUD. 09:59.940 --> 10:08.370 But we're only inside this if if we succeed and we should now we have the HUD we want to call get overlay 10:08.370 --> 10:09.990 widget controller on the HUD. 10:09.990 --> 10:10.260 Right? 10:10.260 --> 10:15.000 We want to say Aura HUD get overlay widget controller. 10:15.000 --> 10:18.480 But this getter requires an F widget controller params. 10:18.480 --> 10:24.030 We need this struct and we need to fill it in with the four key variables, which means we need to make 10:24.030 --> 10:24.960 sure we have those. 10:24.960 --> 10:31.140 So before we get ahead of ourselves and try to call that function, we need those four variables. 10:31.140 --> 10:35.400 We already have the player controller, but we also need the player state. 10:35.430 --> 10:37.290 We can get that from the player controller. 10:37.290 --> 10:44.790 We can say A or a player state A or a player state. 10:45.160 --> 10:51.000 We'll call this PS and we can get that from PC by calling get Player State. 10:51.030 --> 10:56.970 Now, the reason I made it an Or player state is because get player state can take an input template 10:56.970 --> 10:57.510 parameter. 10:57.510 --> 11:01.740 So we can just specify or a player state right there. 11:02.190 --> 11:03.720 And now we have the player state. 11:03.750 --> 11:08.580 Now we also need the ability system component and the attribute set. 11:09.000 --> 11:14.550 Well we cast to or player state or a player state has functions for both of those. 11:14.550 --> 11:20.940 So we can say PS, get attribute set, get ability system component, how convenient. 11:20.940 --> 11:30.420 So let's make a new ability system component pointer called ASC and we'll initialize it with PS, get 11:30.450 --> 11:35.490 ability system component and we'll make a new attribute set as well. 11:36.770 --> 11:37.670 That's a pointer. 11:37.670 --> 11:42.140 We'll call it a s and we'll use P get attribute set. 11:43.610 --> 11:46.400 So now we have the four key variables. 11:46.400 --> 11:48.710 We can make those widget controller params. 11:48.710 --> 11:57.590 Let's make a const f widget controller params called widget controller params. 11:57.740 --> 12:03.060 And this struct has a constructor that takes the four key variables in the following order. 12:03.080 --> 12:09.080 Player controller player state ability system component attribute set. 12:09.260 --> 12:11.510 And we have all four here. 12:11.690 --> 12:14.630 Now this is an incomplete type, isn't it? 12:14.660 --> 12:16.970 Because where is it defined? 12:17.010 --> 12:18.980 F widget controller params. 12:19.400 --> 12:21.910 Well, let's remind ourselves. 12:21.920 --> 12:26.870 Let's go to a widget controller and back into the header file. 12:27.050 --> 12:28.070 Here it is. 12:28.100 --> 12:30.200 F Widget controller params. 12:30.200 --> 12:32.510 It's an aura widget controller. 12:32.630 --> 12:40.040 So here in our blueprint library, let's include or a widget controller we don't need or a player controller. 12:40.040 --> 12:46.710 So I'm going to go ahead and just replace this, include with aura widget controller which exists in 12:46.710 --> 12:53.550 actually UI slash widget controller slash aura widget controller. 12:54.040 --> 12:56.320 And now we have our widget controller params. 12:56.320 --> 13:05.140 All we need to do now is get our HUD and call get overlay widget controller passing in widget controller 13:05.140 --> 13:09.790 params and this function needs to return that overlay widget controller. 13:09.790 --> 13:12.640 So we just need to return that and we're done. 13:12.640 --> 13:20.020 And by the end of this, if we make it to the end and we shouldn't, as long as we've reached this return, 13:20.110 --> 13:24.940 if we make it to the end, we'll return a null pointer, no big deal. 13:24.940 --> 13:31.960 So now we have this blueprint, pure function that we can call from a blueprint to get the overlay widget 13:31.960 --> 13:32.880 controller. 13:32.890 --> 13:34.740 Why don't we just test it out? 13:34.750 --> 13:35.740 Let's go ahead and run. 13:35.740 --> 13:37.330 I'm going to run in debug mode. 13:38.480 --> 13:42.530 And I'll go ahead and open the last blueprint I had open. 13:42.650 --> 13:50.930 And here in overlay, I'm going to just zoom in anywhere and right click and type in git overlay and 13:50.930 --> 13:51.410 look at that. 13:51.410 --> 13:58.610 We have get overlay widget controller under the category or ability system library, sub category widget 13:58.610 --> 13:59.420 controller. 13:59.420 --> 14:06.110 And if we click that it's a blueprint, pure function, it requires a world context object we can pass 14:06.110 --> 14:09.680 in usually this or self here in blueprint. 14:09.680 --> 14:16.640 If I wanted to get a reference to self and pass that in and the return value is an overlay widget controller 14:16.640 --> 14:18.260 object reference. 14:18.260 --> 14:25.520 So we're getting the overlay widget controller and we're getting it by calling the HUD function get 14:25.520 --> 14:32.240 overlay widget controller, which as we know will return the one and only overlay widget controller 14:32.240 --> 14:33.530 if it exists. 14:33.530 --> 14:40.800 But if it does not exist yet, it will construct a new one, initializing it with the four key variables. 14:40.800 --> 14:42.560 That's why we have to pass those in. 14:42.570 --> 14:48.360 So now that we know how to do this and we've done it with the overlay widget controller, what's stopping 14:48.360 --> 14:49.650 us from doing it? 14:49.650 --> 14:54.780 For the attribute menu Widget controller We have all the tools. 14:54.780 --> 14:57.870 We can do it, so we're going to do that next. 14:57.870 --> 14:59.340 So excellent job. 14:59.340 --> 15:02.340 I'm going to go ahead and save all in the editor. 15:02.370 --> 15:05.460 Close out and I'll see you in the next video.