WEBVTT 00:06.990 --> 00:08.220 Welcome back. 00:08.340 --> 00:16.350 As you can see, my boring checkered floor has been replaced with my more exciting tiled floor. 00:16.350 --> 00:19.500 And when I press play, it looks a lot better. 00:19.500 --> 00:28.770 Although I do feel like my character's spring arm is a little short, so I might just go into my character 00:28.770 --> 00:35.040 ora ora character and bring that spring arm out just a bit. 00:35.140 --> 00:38.060 Looks like my target arm length is in the four hundreds. 00:38.070 --> 00:40.740 I'm going to bring it up to 7 or 800 or so. 00:42.110 --> 00:45.170 That's a little bit more appropriate for a top down, I think. 00:45.260 --> 00:47.650 And we're good to go. 00:47.660 --> 00:55.400 Now in this video, we're concerned with making a new ability and I'd like a projectile spell. 00:55.520 --> 00:57.500 So we're going to make one of those. 00:57.530 --> 01:04.490 Let's go into C plus plus classes or aura, public ability system and abilities. 01:04.520 --> 01:12.440 Now we are planning on spawning fireballs, but this C plus plus class is not going to be specific to 01:12.440 --> 01:13.130 fire. 01:13.160 --> 01:16.010 This is going to be a projectile spell. 01:16.010 --> 01:17.480 It could be used for fireballs. 01:17.480 --> 01:20.410 It could be used for any kind of projectile. 01:20.420 --> 01:24.380 So I'm not going to put it in a fire folder or anything like that. 01:24.380 --> 01:26.870 I'm just going to put it right here in abilities. 01:26.870 --> 01:30.560 So we'll go ahead and make a new C plus plus class here. 01:30.560 --> 01:39.710 Choose all classes and for this we're going to choose aura gameplay ability because we want to use our 01:39.710 --> 01:47.880 project wide base ability class and that way it'll inherit anything that all of our abilities need, 01:47.880 --> 01:50.820 such as the startup input tag and so on. 01:50.820 --> 01:54.090 So we're going to go ahead and create that class. 01:54.090 --> 01:59.820 I'm going to call this aura projectile spell. 01:59.850 --> 02:01.620 Let's go ahead and create the class. 02:01.620 --> 02:03.270 I'm going to close the editor. 02:04.040 --> 02:10.190 And let's see what we get in our ability system Abilities folder. 02:10.190 --> 02:12.500 We have Aura projectile spell. 02:12.500 --> 02:14.750 So here's the H file. 02:14.750 --> 02:16.310 I'm going to drag it over. 02:16.310 --> 02:22.450 I'm going to open the CPP file and we've got them open here and that's great. 02:22.460 --> 02:26.900 So what does our projectile spell C plus plus class need? 02:26.900 --> 02:30.920 Well, for one, we're going to want to spawn a projectile and we'll get to that. 02:30.920 --> 02:34.340 But what does the gameplay ability class have? 02:34.340 --> 02:37.760 We know that the Blueprint has an Activate event, right? 02:37.790 --> 02:45.500 Well, if we go into aura gameplay ability and right click on new gameplay ability and go to declaration 02:45.500 --> 02:48.950 or usages, here's the gameplay ability class. 02:49.190 --> 02:56.990 Now I highly recommend that you skim through this class just like you did hopefully for the ability 02:56.990 --> 02:58.250 system component. 02:58.280 --> 03:05.940 So if you're so inclined and I do recommend it, pause the video here and go through this whole header 03:05.940 --> 03:13.290 file and read the comments and skim the names of the functions and variables just so you kind of get 03:13.290 --> 03:18.180 an idea of all that the gameplay ability class has and is capable of. 03:18.180 --> 03:21.180 So you don't have to do it, but I highly recommend it. 03:21.180 --> 03:24.990 So go ahead and pause the video now and skim through the class. 03:25.840 --> 03:26.410 Okay. 03:26.410 --> 03:31.270 So hopefully you paused the video and you read through game ability. 03:31.960 --> 03:39.580 And if you did and I think I know you did, then you now know more about gameplay abilities than most 03:39.580 --> 03:41.470 people out there using gas. 03:41.500 --> 03:42.520 It's true. 03:42.550 --> 03:48.400 Just going through and reading these comments will be very enlightening and is probably opened your 03:48.400 --> 03:52.180 eyes to a lot of the things that a gameplay ability can do. 03:52.210 --> 03:57.700 Now you've probably noticed as you were going through that a lot of the comments say that some of these 03:57.700 --> 04:04.660 things are only for instanced abilities, so you're already seeing the limitations of non instanced 04:04.660 --> 04:05.170 abilities. 04:05.170 --> 04:07.270 They can't do certain things right? 04:07.270 --> 04:15.150 And that just comes down to them not being instanced and not able to store any state inside of them. 04:15.160 --> 04:24.250 Now you've seen that there are a lot of functions, but they all seem to center around this activate 04:24.280 --> 04:25.700 ability right? 04:25.700 --> 04:33.410 Activate ability seems to be the most important out of this entire thing, which I'm sure you have noticed. 04:33.410 --> 04:41.240 And if we search for activate ability and we see that there are lots of functions related to it, such 04:41.240 --> 04:43.340 as can activate ability and so on. 04:43.340 --> 04:50.900 But if we keep searching until we find the actual activate ability function, there's a nice big comment 04:50.900 --> 04:54.920 that says this is the main function that defines what an ability does. 04:55.130 --> 05:02.090 Now there are two versions of many of these functions, and you may have noticed that these two versions 05:02.120 --> 05:03.890 are all new functions. 05:03.910 --> 05:05.870 They're all exposed to Blueprint. 05:05.960 --> 05:13.070 K2 is a sort of legacy convention that a lot of engine classes will have in front of their functions 05:13.070 --> 05:15.050 if they're exposed to blueprint. 05:15.080 --> 05:20.620 You see, before Blueprint there used to be kismet and there was a kismet too. 05:20.630 --> 05:25.130 So Kismet version two and then Blueprint came around. 05:25.130 --> 05:26.450 So now we have Blueprint. 05:26.450 --> 05:32.630 So you can kind of think of K2 as Blueprint BP, Right? 05:32.780 --> 05:38.900 K2 is just a legacy convention and you'll see it throughout gas and other engine classes. 05:38.900 --> 05:41.270 So that's just what K2 means. 05:41.270 --> 05:49.250 It's the K2 version or the blueprint version of various functions that exist, and they are often separated 05:49.250 --> 05:52.520 into the native version, which is just C plus plus. 05:52.520 --> 05:53.750 There's no new function. 05:53.750 --> 05:56.510 It's not exposed to reflection or blueprint. 05:56.510 --> 06:02.030 And then the K2 version, which is usually either a blueprint, implementable event, blueprint, callable 06:02.060 --> 06:03.770 blueprint, pure and so on. 06:03.980 --> 06:09.290 So Activate Ability has a native version and as we can see, it's virtual. 06:09.290 --> 06:15.890 And then there's the void K2 Activate ability, which is a blueprint implementable event. 06:15.890 --> 06:18.770 And that means it's an event and the event graph. 06:18.770 --> 06:23.690 Right now, if you're confused, why didn't we see K2 on the event? 06:23.720 --> 06:29.860 Well, that's because the function macro has this display name that says activate ability. 06:29.860 --> 06:32.560 That's what the display name will be in Blueprint. 06:32.560 --> 06:37.390 So that's just one of those you function specifiers that you can use. 06:37.420 --> 06:43.750 Now, there are other associated functions related to activate ability, but activate ability is the 06:43.750 --> 06:49.240 one that we want to override and we don't actually call activate ability. 06:49.240 --> 06:51.520 That is not how we activate abilities. 06:51.520 --> 06:54.730 We activate them by trying to activate them, right? 06:54.730 --> 07:00.160 Because there are things that can prevent them from being activated, such as blocked tags and so on. 07:00.160 --> 07:04.300 So we're concerned with overriding activate ability. 07:04.300 --> 07:10.090 And if we do that in our own custom gameplay ability, then we can determine what happens when that 07:10.090 --> 07:11.950 ability is activated. 07:11.950 --> 07:17.050 So I'd like to override activate ability in or a projectile spell. 07:17.080 --> 07:19.930 Now what is this, a protected function? 07:19.930 --> 07:20.890 Public function? 07:20.890 --> 07:23.710 Well, writer says right here it's a protected method. 07:23.710 --> 07:29.540 So we're going to create a protected section right here in Aura projectile spell. 07:30.760 --> 07:36.190 And we're going to override this virtual function, virtual void, activate ability. 07:36.280 --> 07:38.740 And it has a kind of a long signature. 07:38.740 --> 07:39.940 It's not that long. 07:39.950 --> 07:43.240 It has a gameplay ability spec handle. 07:43.240 --> 07:46.030 So we have access to the spec handle itself. 07:46.030 --> 07:52.450 We've seen how useful spec handles are and in debug mode we've seen that we can dig deep into these 07:52.450 --> 08:00.010 types to find that they often have these pointers right for the data underneath the handle. 08:00.010 --> 08:04.000 The handle is just a lightweight thing we pass around just like a pointer. 08:04.000 --> 08:10.090 We have the gameplay ability actor info and if you read through gameplay ability you'll see that the 08:10.090 --> 08:15.010 comment says that this contains lots of useful information pertaining to the ability. 08:15.010 --> 08:20.470 It's owner controller, lots of different things, so it's got the actor info in it. 08:20.500 --> 08:26.800 We have activation info again, another struct filled with lots of stuff and we can always peek those 08:26.800 --> 08:29.200 structs to see the member variables in them. 08:29.200 --> 08:31.880 But we'll get plenty of experience using these. 08:31.880 --> 08:32.720 Don't worry. 08:32.720 --> 08:34.940 And then there's gameplay event data. 08:34.940 --> 08:41.630 If this ability was activated because of an event and I know that doesn't make any sense to you just 08:41.630 --> 08:47.870 yet, but we have that data and we're going to learn how to activate abilities with gameplay events 08:47.870 --> 08:48.650 as well. 08:48.650 --> 08:51.080 So don't worry if that makes zero sense. 08:51.110 --> 08:52.850 It will when we get to that. 08:52.850 --> 08:54.020 Gas is big, right? 08:54.020 --> 08:55.610 Gas is a huge system. 08:55.610 --> 08:57.290 There's a lot of things to take in. 08:57.290 --> 09:04.520 So that's why I think it's a good idea to just skim right, to just take a look at this whole thing 09:04.520 --> 09:10.730 and don't really dig deep into any one thing, but just notice all the things that are here. 09:10.820 --> 09:12.530 There really aren't that many of them. 09:12.890 --> 09:17.630 So we have activate ability and we're going to go ahead and generate the definition. 09:17.630 --> 09:19.580 We're going to let it call super. 09:19.580 --> 09:21.200 And what are we going to do? 09:21.200 --> 09:24.650 Let's well, why don't we just print a debug message? 09:24.650 --> 09:30.470 So I'm going to add a debug message, but rather than the add on screen debug message function, I'm 09:30.470 --> 09:35.720 so fond of, I'm instead going to use you kismet system library. 09:36.290 --> 09:37.520 Print string. 09:37.520 --> 09:37.940 Why? 09:37.970 --> 09:43.850 Because this is actually the print string that we use in the event graph in blueprints. 09:43.850 --> 09:46.430 This is that print string. 09:46.430 --> 09:52.250 And if we're using the same one then we can see which of these is printed first as they're all going 09:52.250 --> 09:54.170 to use the same function. 09:54.170 --> 10:00.800 And we'll see, based on the order of messages printed to the screen, which of these is called first? 10:00.800 --> 10:05.420 So for print string and by the way, you have to include kismet system library. 10:05.420 --> 10:08.870 For this we can pass in a world context object. 10:08.870 --> 10:11.420 This will do and an F string. 10:11.420 --> 10:17.630 And I'm just going to say activate ability and parentheses C plus plus. 10:18.480 --> 10:21.240 Now for the next argument, be print to screen. 10:21.240 --> 10:22.650 We want that to be true. 10:22.680 --> 10:24.900 We do want to print this to the screen. 10:24.930 --> 10:26.620 Do we want to print it to the log? 10:26.640 --> 10:27.030 Sure. 10:27.030 --> 10:28.890 Let's print it to the log as well. 10:28.890 --> 10:36.150 And linear color is the color and we can use any color we want. 10:36.300 --> 10:38.520 How about yellow? 10:38.790 --> 10:45.540 And for the duration we'll just use three and we'll leave the key name at none. 10:45.540 --> 10:53.640 So that way we'll see all the messages older and newer, and we can create a blueprint from this and 10:53.640 --> 10:57.090 activate the ability and see what happens. 10:57.360 --> 11:02.130 And from here in the editor, I want to create a blueprint based on this. 11:02.310 --> 11:07.500 I'm just going to click open just to see what I had open I had or a character and firebolt That's perfect. 11:07.500 --> 11:12.210 I'll keep those open and let's make a blueprint based on our new gameplay ability. 11:12.210 --> 11:18.580 I'm going to go into blueprints, ability system, gameplay abilities, fire and Firebolt. 11:18.580 --> 11:23.170 I know it's kind of a long path name, but this keeps us organized. 11:23.200 --> 11:29.260 Now I'm going to make a blueprint based on my new Aura projectile spell, so I'm going to search for 11:29.260 --> 11:31.420 or projectile spell. 11:31.510 --> 11:39.430 Select that and call this a for gameplay ability and this can be firebolt. 11:40.580 --> 11:47.240 So we have a new aura projectile spell called Firebolt and we usually prefix them with a as I think 11:47.240 --> 11:49.760 I mentioned before, for gameplay ability. 11:50.330 --> 11:57.890 Now here's our event activate ability and we know that we have activate ability in C plus plus as well. 11:57.890 --> 12:04.100 And from right here in the blueprint I'd like to print a string and for this one I'll go ahead and give 12:04.100 --> 12:12.110 it a duration of three seconds and we'll say activate ability and parentheses Blueprint. 12:14.280 --> 12:15.660 And there we go. 12:15.810 --> 12:20.920 And if we go back to class defaults and take a look at input. 12:20.940 --> 12:25.380 Let's give this a startup input tag of lab for left mouse button. 12:25.380 --> 12:31.740 And that way we can give this ability to our character and we can left click to activate it. 12:31.740 --> 12:33.270 I'd like to see what happens. 12:33.270 --> 12:39.780 So I'm going to compile and save and go to Aura character and search for abilities. 12:40.490 --> 12:42.390 Here's my startup abilities. 12:42.410 --> 12:50.330 I'm going to go ahead and remove that test gameplay ability and add my new game Firebolt ability. 12:50.330 --> 12:52.430 So we should start with that ability. 12:52.430 --> 12:58.670 And we know that because we set its startup input tag to LMB that we should be able to activate it with 12:58.670 --> 13:00.140 the left mouse button. 13:00.440 --> 13:07.160 And if we activate the ability by clicking on an enemy, we have both messages, the blueprint one there 13:07.160 --> 13:15.950 and after that the yellow C plus plus version, which is called after as newer messages are on top. 13:16.840 --> 13:17.260 Great. 13:17.260 --> 13:23.680 So that proves to us that we have both the blueprint and C plus plus version running, but we want to 13:23.680 --> 13:25.420 do more interesting things. 13:25.420 --> 13:27.960 We want to actually spawn projectiles. 13:27.970 --> 13:31.630 So in the next video, we're going to be concerned with doing that. 13:31.630 --> 13:35.500 So this ability is about to get a lot more dangerous. 13:35.530 --> 13:36.790 I'll see you soon.