WEBVTT 00:06.810 --> 00:08.010 Welcome back. 00:08.280 --> 00:14.760 So we've taken a look at the gameplay effect context struct. 00:14.790 --> 00:21.150 We've seen that it exists here in gameplay effect types and we've seen the benefits and the limitations 00:21.150 --> 00:21.910 of it. 00:21.930 --> 00:28.800 And I'd like to create a custom gameplay effect context struct derived from this one. 00:28.950 --> 00:37.380 And that way we can add additional fields to this struct that we may wish to set on the effect context 00:37.380 --> 00:42.420 and pass through and perhaps change and manipulate based on situations. 00:42.420 --> 00:48.930 I'd like to have specifically a couple of booleans in here for whether or not we've gotten a block or 00:48.930 --> 00:49.980 a critical hit. 00:50.670 --> 00:57.390 So since I'm going to be creating my own gameplay effect context struct, I'd like to create it in a 00:57.390 --> 01:03.420 new header file and because I may be creating more of my own types for the ability system, I'm going 01:03.420 --> 01:10.440 to store them in a header file here in the public section and I'm going to create that header file here. 01:10.440 --> 01:15.090 I'm going to right click on my public folder, go to add and select file. 01:15.090 --> 01:19.410 And this is going to be for my ability system custom types. 01:19.410 --> 01:24.060 So I'm going to call this aura ability types. 01:25.160 --> 01:30.930 It could be ability system types, but I'm going to keep the name a little bit shorter and call it aura. 01:30.950 --> 01:32.930 Ability types Dot H. 01:33.020 --> 01:34.310 I'm going to click okay. 01:34.310 --> 01:38.390 And Ryder asks if I'd like to add this to Jet. 01:38.420 --> 01:44.330 I'm going to click Don't Ask again and cancel because I prefer to add these things by myself through 01:44.330 --> 01:45.020 the git bash. 01:45.020 --> 01:52.970 So I'm going to hit cancel and now I have aura ability types, dot h and I'm going to be creating definitions 01:52.970 --> 01:57.830 for functions on my types and I'd like those to be in their CPP file. 01:57.830 --> 02:05.810 So I'm going to right click on the private folder, go to add and select file and this will be Aura 02:05.840 --> 02:08.270 ability types dot CPP. 02:09.050 --> 02:15.620 I'm going to click okay here and the first thing I'm going to do in Aura ability types, CPP is include 02:15.620 --> 02:17.030 that header file. 02:17.030 --> 02:21.590 So I'm going to include aura ability types dot h here. 02:21.950 --> 02:29.520 Now here in aura ability types, I'm going to declare a new struct and this will be derived from the 02:29.730 --> 02:31.890 gameplay effect context struct. 02:31.890 --> 02:40.980 So I'm going to say struct and I'm going to call this f aura gameplay effect context and it's going 02:40.980 --> 02:46.410 to be publicly derived from F gameplay effect context. 02:46.440 --> 02:54.000 That of course means I need to include the header file for gameplay effect context and writer just went 02:54.000 --> 02:55.740 ahead and did it for me. 02:55.740 --> 02:57.900 It included gameplay effect types. 02:57.900 --> 02:59.040 Dot h. 02:59.220 --> 03:03.630 That's where gameplay effect context is defined. 03:04.050 --> 03:09.120 Now writers telling me that the public for a struct is redundant, right? 03:09.120 --> 03:11.220 This is the behavior we get with a struct. 03:11.220 --> 03:13.440 Anyway, I'm going to leave it there. 03:13.530 --> 03:19.320 I'm also going to make this a use struct with blueprint type and give it a generated body. 03:21.580 --> 03:25.030 And I'm going to have multiple access levels. 03:25.030 --> 03:31.420 So I'm going to stick a public right here, even though I know that structs have a public body by default. 03:32.020 --> 03:37.350 I'm going to have a public section labeled there and a protected section. 03:37.360 --> 03:40.120 And again, the public here is redundant. 03:40.360 --> 03:44.860 Even if I add variables and functions here, they would be public anyway. 03:44.860 --> 03:48.760 So this is just because I want this to say public. 03:49.150 --> 03:53.710 Okay, so we've created an aura gameplay effect context struct. 03:53.740 --> 03:57.640 Now we can't just use this struct just because we've created one. 03:57.670 --> 04:02.920 There are a number of steps to go through before we can actually use this and we're actually going to 04:02.920 --> 04:09.640 need to set the gameplay effect context used by our project to this particular struct and we'll get 04:09.640 --> 04:10.720 to that later. 04:10.720 --> 04:19.360 But for now I'd just like to add a couple of things to the struct and before we even add our new booleans, 04:19.360 --> 04:25.180 the whole reason why we wanted these, there are a couple of things that we need before we can get started 04:25.180 --> 04:30.910 on that and we can learn what those things are by looking at the gameplay effect, context, struct 04:30.910 --> 04:32.600 and gameplay effect types. 04:32.600 --> 04:38.690 So here in gameplay effect types, there are just a couple of things that our gameplay effect context 04:38.720 --> 04:39.920 needs to have. 04:39.920 --> 04:47.450 And if we scroll down towards the bottom of this struct we'll come across a function called get script 04:47.450 --> 04:48.320 struct. 04:48.440 --> 04:50.210 Now what is a script struct? 04:50.210 --> 04:56.810 Well, if you're familiar with the static class function on most you objects, you'll know that it returns 04:56.840 --> 04:57.860 a new class. 04:57.890 --> 05:05.030 Now, if you don't know what a class is, it's generated for each class in the engine that's derived 05:05.030 --> 05:08.300 from a new object for the reflection system. 05:08.300 --> 05:16.190 So if you have a new actor class, for example, a new class is generated for that for the reflection 05:16.190 --> 05:19.700 system structs also have a version of this. 05:19.730 --> 05:21.410 It's called a script struct. 05:21.440 --> 05:28.580 So when you create a struct that's capable of being exposed to the reflection system, a script struct 05:28.610 --> 05:31.340 is created for the reflection system. 05:31.340 --> 05:38.540 Think of it as a reflection of that struct, much like a class is a reflection of the object. 05:38.570 --> 05:46.580 Now static struct is a function just like static class that returns that and our gameplay effect context 05:46.610 --> 05:48.680 has a virtual function. 05:48.680 --> 05:53.090 Get script struct which just returns that static struct. 05:53.090 --> 05:57.080 As you can see it just calls static struct and returns that. 05:57.080 --> 06:01.850 And notice the comment says subclasses must override this so we can override it. 06:01.850 --> 06:02.990 I'm going to go ahead and copy it. 06:02.990 --> 06:10.550 This is in the public section here, so we're just going to override it and stick it in our public section 06:10.550 --> 06:12.920 and aura ability types dot h. 06:13.160 --> 06:19.010 And it looks like I actually defined my class in the CPP file. 06:19.010 --> 06:24.980 You might have noticed that I actually meant for this to be in the header file, but that's okay. 06:24.980 --> 06:29.780 I can just cut it and I can stick it right here in the header file. 06:29.780 --> 06:30.920 No big deal. 06:31.010 --> 06:35.900 And in the public section we're going to override get script struct. 06:35.900 --> 06:40.580 So I'm going to copy these lines here and just paste them here in the public section. 06:41.390 --> 06:41.870 Okay. 06:41.870 --> 06:44.750 So that's one thing that we need. 06:44.780 --> 06:47.720 Let's go back and take a look at what else we have. 06:47.720 --> 06:53.750 We're going to scroll down and there's a very important function at the end of the public section called 06:53.750 --> 06:55.040 Net Serialize. 06:55.040 --> 07:00.350 And the comment says custom serialization subclasses must override this. 07:00.560 --> 07:05.510 Now, net Serialize determines how this struct is serialized. 07:05.690 --> 07:12.920 Now serialization is necessary if you're going to save one of these structs, for example, or send 07:12.920 --> 07:14.480 it across the network. 07:14.780 --> 07:18.200 These are things that require serialization. 07:18.200 --> 07:25.460 In other words, take a struct, convert it into bits, zeros and ones and send those bits in a stream 07:25.460 --> 07:26.780 across the internet. 07:26.810 --> 07:31.780 If you want to be able to replicate something, it needs this net serialize. 07:31.790 --> 07:33.350 Interesting, right? 07:33.350 --> 07:39.260 So we're going to learn all about this in the next few videos, but for now we're just going to override 07:39.260 --> 07:40.400 it as we have to. 07:40.400 --> 07:44.600 So we're going to go to aura ability types and override net serialize. 07:44.630 --> 07:46.340 I'll go ahead and. 07:46.950 --> 07:49.110 Generate a definition for it. 07:49.290 --> 07:51.010 I'm going to empty it out. 07:51.030 --> 07:54.270 So we're going to need to return something from this. 07:54.780 --> 07:56.940 For now, I'm just going to return. 07:56.940 --> 07:59.670 True until we fill this out. 07:59.670 --> 08:01.470 But we do need to fill this out. 08:01.800 --> 08:03.680 And what are we going to fill it out with? 08:03.690 --> 08:09.720 Well, we need to specify how our struct is going to be serialized, which means we have to learn about 08:09.720 --> 08:10.750 how that works. 08:10.770 --> 08:17.940 Now we can learn about how that works by seeing the definition for net serialize for the gameplay effect 08:17.940 --> 08:18.950 context. 08:18.960 --> 08:27.000 So I can go to gameplay effect types dot CP and search for gameplay effect context net serialized function 08:27.000 --> 08:27.570 here. 08:27.780 --> 08:34.290 And if you take a look at net serialize for the first time it's going to look quite cryptic. 08:34.320 --> 08:37.440 There are some things in here that look a lot like magic. 08:37.530 --> 08:42.390 So for that reason we're going to need to have a discussion about this. 08:42.480 --> 08:45.450 Notice that net Serialize takes three inputs. 08:45.550 --> 08:52.210 One is an archive passed in by reference and it's not a const reference, so that should tip you off 08:52.210 --> 08:54.070 about this input parameter. 08:54.070 --> 09:01.300 It should tell you, well, maybe this function is designed to fill it in somehow to change this f archive 09:01.330 --> 09:03.100 mystical object here. 09:03.580 --> 09:09.910 There's also a u package map called map passed in and a boolean called B out Success. 09:10.210 --> 09:12.790 Now let's take a look at what's happening here. 09:12.820 --> 09:19.990 Notice that we're performing some if checks and all of these if checks, every single one of them has 09:19.990 --> 09:24.670 to do with one of the variables stored on this gameplay effect. 09:24.670 --> 09:29.980 Context struct notice we have the actors, we have the hit results has world origin. 09:29.980 --> 09:30.640 Right? 09:30.640 --> 09:34.450 So it's checking something about these, right? 09:34.450 --> 09:38.950 It's looking at if instigator is valid, if effect causer is valid. 09:38.950 --> 09:44.050 So it's checking things and then it's doing something that looks a little bit strange. 09:44.320 --> 09:48.220 And all of this is in an if r dot is saving. 09:48.220 --> 09:52.240 So this F archive has a dot is saving, right? 09:52.240 --> 09:53.830 This is saving function. 09:53.830 --> 10:01.480 Then we call a function called serialized bits on it and then have another series of if statements checking 10:01.480 --> 10:08.980 another sort of cryptic expression here before doing something with the R, this archive object. 10:09.160 --> 10:14.500 And it looks like each of these has to do with the variables here in the struct again. 10:14.500 --> 10:21.580 So at a high level, in a nutshell, net serialize is just serializing each of the member variables 10:21.580 --> 10:28.120 in this struct, saving it into an archive if the struct is being saved. 10:28.120 --> 10:33.820 But if the struct is not being saved, if it's being loaded, well then we're getting that data out 10:33.820 --> 10:35.020 of the archive. 10:35.260 --> 10:36.280 Kind of confusing. 10:36.280 --> 10:36.640 Right? 10:36.640 --> 10:39.280 So we're going to talk about this in the next video. 10:39.280 --> 10:45.340 For now, it's enough to know at a high level what this net serialized does and that we need to override 10:45.340 --> 10:45.820 it. 10:45.820 --> 10:50.320 But how are we going to override it when we don't know what's going on here? 10:50.320 --> 10:57.940 And especially if we're going to have even more variables here that don't exist in gameplay effect context. 10:58.090 --> 11:01.450 So in the next video, we'll learn about how Net Serialize works. 11:01.450 --> 11:07.960 But before we wrap up, let's go ahead and add those variables that we'd like on our custom gameplay 11:07.960 --> 11:09.310 effect context. 11:09.310 --> 11:11.170 So I'm going to add those. 11:11.200 --> 11:14.710 They're going to be protected and they're just going to be balls. 11:14.710 --> 11:23.860 There's going to be one bool called B is critical hit and it'll be set to false by default and we're 11:23.860 --> 11:27.760 going to give it a new property and I'm going to have another one. 11:27.790 --> 11:31.270 B is block or is blocked hit. 11:31.270 --> 11:33.130 I'd like that one to be first, actually. 11:33.130 --> 11:35.320 So B is blocked. 11:35.350 --> 11:36.700 Hit equals false. 11:36.700 --> 11:38.890 We have both of these and they're protected. 11:39.010 --> 11:45.880 Now, I'd like to create functions to retrieve these that are public so that we can get them from outside 11:45.880 --> 11:50.290 the class and functions to set them basically getters and setters. 11:50.440 --> 11:59.680 So up here in the public section I'm going to make a bool is critical hit const function that returns 11:59.710 --> 12:02.320 B is critical hit. 12:03.330 --> 12:07.470 And I'll make a bool is blocked hit. 12:09.680 --> 12:13.950 Also const that returns B is blocked. 12:13.970 --> 12:14.540 Hit. 12:15.230 --> 12:17.630 And then I'll make a void. 12:17.630 --> 12:28.430 Function called set is critical hit, which takes a bool called B in is critical hit. 12:30.100 --> 12:31.960 And sets B is critical. 12:31.960 --> 12:37.060 Hit equal to b n is critical hit simple. 12:37.240 --> 12:44.230 And we'll have another one for is blocked hit so void and this will be set is blocked hit. 12:45.570 --> 12:49.800 It'll take a bull called B in is blocked hit. 12:51.630 --> 12:58.740 And it's going to set B is blocked, hit equal to B in is blocked, hit. 12:58.950 --> 12:59.670 Cool. 12:59.670 --> 13:07.530 So we have our new variables justifying going through all this trouble to make our own effect context. 13:07.530 --> 13:12.510 But the only problem is we don't have net serialize filled out. 13:12.510 --> 13:15.480 This function needs to be filled out. 13:15.510 --> 13:24.150 And one last very important detail before we give this a test compile is we have a generated body here. 13:24.150 --> 13:28.260 That means we need a generated h file for this header file. 13:28.260 --> 13:37.680 And in fact, another safeguard is to use pragma once at the top so this header can't be included more 13:37.680 --> 13:38.970 than once anywhere. 13:39.180 --> 13:45.420 So we got pragma once and we're also going to include all the ability types. 13:47.570 --> 13:50.630 Dot generated Dot h. 13:52.210 --> 13:53.920 Now I'm going to compile this. 13:56.140 --> 13:59.100 And with that, we have a successful compile. 13:59.110 --> 14:01.210 Everything's looking good so far. 14:01.240 --> 14:02.830 The next step is to fill out. 14:02.860 --> 14:07.930 Net serialize and that involves learning how the gameplay effect context. 14:07.960 --> 14:12.700 Net serialize class works and that's in gameplay effect type scope. 14:12.970 --> 14:18.880 So in the next video we're going to discuss this and demystify it so that we can put this type of thing 14:18.910 --> 14:21.550 to use in our gameplay effect context. 14:21.550 --> 14:22.910 And we'll do that next. 14:22.930 --> 14:24.100 I'll see you soon.