WEBVTT 00:07.090 --> 00:08.080 Welcome back. 00:08.080 --> 00:13.780 Now our fireballs for the fire blast ability are using on hit, aren't they? 00:13.810 --> 00:20.860 Now, if we go to actor and open fireball, the aura fireball, we don't have anything here for on hit. 00:20.860 --> 00:23.770 We're just using the inherited on hit function. 00:23.770 --> 00:30.070 And if we go to aura projectile, we can see what that function does on hit right here. 00:30.070 --> 00:36.820 It results in playing a sound, spawning a Niagara system, and stopping the looping sound and setting 00:36.820 --> 00:37.390 a boolean. 00:37.390 --> 00:43.000 Now this is great, but this is sort of the vanilla way to do it. 00:43.000 --> 00:50.710 This is just using gameplay statics and you Niagara function library to play sounds and spawn particles. 00:50.710 --> 00:53.890 What if we want to take advantage of gameplay cues? 00:54.130 --> 01:01.870 Well, gameplay cues are replicated by default, as we know there are PCs, and even though we've upped 01:01.870 --> 01:09.550 our projects RPC limit per net update to ten, well, we still know that our fire blast ability is spawning 01:09.580 --> 01:18.550 12 of these, so 12 is verging on a bit much for all at once, which is why we've erred on the side 01:18.550 --> 01:22.150 of not using gameplay cues, or at least using them sparingly. 01:22.150 --> 01:23.620 And we're not using them here. 01:23.620 --> 01:25.420 But what if you wanted to anyway? 01:25.420 --> 01:29.710 What if you wanted to use a gameplay cue locally without sending an RPC? 01:29.710 --> 01:36.940 Well, we could do that too, so I'd like to show how to do that with on hit and in fact, ability system 01:36.940 --> 01:44.770 components should all have a set of functions that make it easy to handle gameplay cues locally. 01:44.770 --> 01:45.670 So we'll visit that. 01:45.670 --> 01:52.480 But for now, let's talk about how we can execute a local gameplay cue in or a fireball. 01:52.990 --> 01:58.630 Well, we're already calling on hit, we're calling it on the server, and then in destroyed we're calling 01:58.630 --> 02:01.120 it if B hit is false. 02:01.120 --> 02:01.840 Right? 02:01.840 --> 02:08.680 So really we could take our A fireball and override on hit if we make it virtual. 02:08.830 --> 02:10.480 So that's the way I'd like to do this. 02:10.480 --> 02:13.360 Because if we do that we won't have to change anything else. 02:13.360 --> 02:18.070 We just have to execute a gameplay cue, which means we'll have to make one. 02:18.070 --> 02:19.510 But we'll get to that. 02:19.510 --> 02:20.260 For now. 02:20.260 --> 02:26.770 I'm going to make on hit an aura projectile, a virtual function, and then we can override this virtual 02:26.770 --> 02:29.170 function in Aura Fireball. 02:29.170 --> 02:34.420 So I'm going to go to Aura Fireball dot h in the protected section as this is a protected function. 02:34.420 --> 02:42.250 And I'm going to override on hit and now or a fireball can implement its own definition for this. 02:42.250 --> 02:48.850 And whatever we do by the end of it I'm going to set be hit to true, just like we did in aura projectile 02:48.850 --> 02:49.630 right here. 02:49.630 --> 02:54.940 The only difference is the way we're going to handle these things right now. 02:54.940 --> 02:57.370 We want to stop the looping sound component. 02:57.370 --> 02:57.790 Yes. 02:57.790 --> 03:02.140 So I'm going to copy that part and put that in the aura of fireball version. 03:02.140 --> 03:05.020 And of course looping sound component is private. 03:05.020 --> 03:10.960 So if we're going to use looping sound component in a child class that has to be protected as well, 03:10.990 --> 03:12.430 no problem. 03:13.060 --> 03:19.840 We can take looping sound component, we can cut it from the private section and paste it into the protected 03:19.840 --> 03:20.440 section. 03:20.440 --> 03:27.610 And now our fireball should be able to access it, provided that it includes the correct header file. 03:27.610 --> 03:33.070 Well, we can steal that from our projectile that CPP its audio component. 03:34.450 --> 03:39.280 So we can paste that up here and we should be good to go. 03:39.890 --> 03:40.610 All right. 03:40.610 --> 03:44.180 So on head is overridden and we're stopping the looping sound. 03:44.180 --> 03:47.000 But how do we execute a gameplay cue. 03:47.030 --> 03:52.460 Well, first of all we need to know what the gameplay cue tag is because gameplay cues are executed 03:52.460 --> 03:53.630 by tag. 03:53.660 --> 04:00.020 So for this particular gameplay cue that we're going to create for Fire Blast, we can make a gameplay 04:00.020 --> 04:03.320 cue tag by going to our gameplay tags. 04:03.320 --> 04:04.760 I'm going to do that. 04:05.240 --> 04:09.200 We have most of our gameplay cue tags made inside the engine. 04:09.200 --> 04:13.850 In fact, all of them are made that way, but this one we want to use in C Plus plus. 04:13.850 --> 04:22.640 So I'm going to make a native gameplay tag, and I'm going to call this gameplay cue underscore fire 04:22.640 --> 04:23.660 blast. 04:24.550 --> 04:28.870 And we'll go ahead and define Fireblast in our gameplay tags. 04:28.870 --> 04:33.100 I'm just going to copy one of these and go all the way down to the bottom. 04:33.970 --> 04:43.360 Make a comment that says gameplay queue and paste this and we'll use gameplay queue Fireblast. 04:44.460 --> 04:45.960 And it's going to be gameplay. 04:45.960 --> 04:47.700 Q dot. 04:49.010 --> 04:50.390 Fire blast. 04:51.390 --> 04:57.870 And we'll say fire blast gameplay cue tag. 04:57.870 --> 05:01.620 Now that we have that, we can close our gameplay tags. 05:01.620 --> 05:02.490 We're done with it. 05:02.490 --> 05:07.050 And here in on hit, we'd like to execute a gameplay cue locally. 05:07.050 --> 05:11.400 So how are we going to execute a local gameplay cue? 05:11.850 --> 05:19.860 Well, if we search for gameplay cue manager and we and we go to gameplay cue manager dot H, we can 05:19.860 --> 05:24.030 scroll down and see that there are a number of functions that are very useful. 05:24.620 --> 05:27.470 Here are three static functions right here. 05:27.830 --> 05:32.270 We can add, remove or execute gameplay cues locally. 05:32.600 --> 05:34.220 Non replicated. 05:35.330 --> 05:41.480 Now remember adding is for adding a instance gameplay cue, something that you add to an actor, whereas 05:41.480 --> 05:48.530 executing is just executing something that's either static, a gameplay cue, notify, burst, etc.. 05:48.800 --> 05:56.240 Now I'd like to make a burst notify, so I'm going to use execute gameplay cue non replicated, which 05:56.240 --> 06:00.710 requires a target, a gameplay cue tag and some parameters. 06:00.710 --> 06:04.250 Now our fireball needs to know the target. 06:04.250 --> 06:08.300 And that target has to have an ability system component. 06:08.300 --> 06:12.950 Either it's the avatar actor or the owner actor and so on. 06:12.950 --> 06:16.250 Now our fireball could have an owner. 06:16.250 --> 06:22.010 If we set it, we could get the ability system component from damage effect params, but we're not really 06:22.010 --> 06:23.900 setting that on clients. 06:23.900 --> 06:27.500 We're setting that on the server when we spawn this thing. 06:27.500 --> 06:31.820 Now, how do we set something that the clients will know about? 06:31.820 --> 06:34.340 Well, the owner of all actors is replicated. 06:34.340 --> 06:40.640 So if we go back to our gameplay ability where we're spawning these fireballs, we can set the owner 06:40.640 --> 06:42.800 there or make sure that we're doing so. 06:42.800 --> 06:48.230 Let's go to Aura Fire Blast and go to where we're spawning these fireballs. 06:48.230 --> 06:50.540 We're setting the damage effect params. 06:50.540 --> 06:52.910 We're even setting the return to actor. 06:52.910 --> 06:56.300 We could also set the owner as well. 06:56.360 --> 07:01.610 We can take fireball and call set owner. 07:02.740 --> 07:09.010 And we can simply use the avatar actor from the actor info if we want that to be the owner. 07:09.010 --> 07:13.930 And if we have this set, the owner on all actors is replicated. 07:13.930 --> 07:19.330 So the fireball is going to know on the client who its owner is. 07:19.330 --> 07:25.930 However, we need to make sure that's a valid pointer just in case on hit gets called before that replication 07:25.930 --> 07:29.290 happens, which is unlikely but possible. 07:30.250 --> 07:34.300 So we're going to check if get owner if that's a valid pointer. 07:34.300 --> 07:40.960 And then we can call that static function on gameplay queue manager execute gameplay queue non replicated. 07:41.410 --> 07:44.140 So we're going to get you gameplay queue manager. 07:46.210 --> 07:49.210 Make sure that we have the header file included for that. 07:53.050 --> 08:00.040 So there it is, gameplay queue manager and we can call execute gameplay queue non replicated passing 08:00.040 --> 08:01.000 in the actor. 08:01.000 --> 08:07.030 We're going to use Get owner the gameplay tag we can use for gameplay tags. 08:07.420 --> 08:09.550 Gameplay queue Fireblast. 08:10.410 --> 08:13.500 Now the third parameter is gameplay cue parameters. 08:13.500 --> 08:17.430 We've seen gameplay cue parameters in the editor and blueprint. 08:17.430 --> 08:21.690 This is just an f gameplay cue parameter struct, so we can make one. 08:21.690 --> 08:28.560 We can make an f gameplay cue parameters called cue params, and I mentioned that I'd like this to be 08:28.560 --> 08:35.940 a burst notify, and the burst notify will spawn particles at the location in the cue parameters, so 08:35.940 --> 08:40.860 we can set cue params dot location and we're inside the fireball. 08:40.860 --> 08:42.930 I'm just going to call get actor location. 08:43.980 --> 08:46.560 And we can pass in those Q params. 08:50.810 --> 08:53.030 Now it looks like I made a typo here. 08:53.030 --> 08:54.680 This is for a gameplay tags. 08:54.680 --> 08:58.880 It should be get dot gameplay q fireblast. 08:58.880 --> 09:01.340 So typing a little too hastily there. 09:01.760 --> 09:04.310 But with that we have our gameplay Q params. 09:04.310 --> 09:09.500 We've set the location on it and we're executing gameplay Q non replicated. 09:09.500 --> 09:14.030 With this we can just compile and make our gameplay Q. 09:15.200 --> 09:16.670 Okay, so we're back. 09:16.700 --> 09:19.700 Now the next thing to do is create a gameplay queue. 09:19.700 --> 09:21.680 So I'm going to go to the ability system. 09:21.680 --> 09:25.700 Gameplay cue notifies folder and create a new one. 09:26.310 --> 09:30.000 So we'll go to blueprint gameplay cue. 09:30.000 --> 09:31.170 Notify. 09:31.810 --> 09:38.200 GCN burst and this will be called GC underscore fireblast. 09:38.590 --> 09:42.160 Let's open up GC Fireblast now because I called it Fireblast. 09:42.190 --> 09:44.830 Look at this gameplay queue tag. 09:44.860 --> 09:46.810 Gameplay queue Fireblast. 09:47.140 --> 09:48.370 How amazing! 09:48.370 --> 09:54.580 Now let's go to our burst effects and click plus for burst particles and let's select one. 09:54.580 --> 10:01.930 Now remember we have an explosion and we have nice fire explosion and fire explosion one I'm going to 10:01.930 --> 10:03.460 use fire explosion. 10:03.460 --> 10:05.110 It's this one here. 10:07.420 --> 10:08.890 So that's going to do. 10:08.980 --> 10:11.170 And now for the burst sounds. 10:12.060 --> 10:17.280 We can add one of these and we have an impact sound. 10:17.280 --> 10:19.230 It's called Firebolt Impact. 10:19.230 --> 10:21.150 And that's what this sounds like. 10:23.430 --> 10:25.890 That's the sound our firebolts have been making. 10:27.190 --> 10:36.070 So now that we have burst particles and we have burst sounds, we can go ahead and test out executing 10:36.070 --> 10:37.930 these gameplay queues locally. 10:40.440 --> 10:45.390 So we'll try on the server in a single player game, I'm going to press two. 10:47.480 --> 10:50.300 There's our gameplay cue executing. 10:50.300 --> 10:51.020 Looks good. 10:51.020 --> 10:52.700 Looks like we leveled up to. 10:55.400 --> 10:58.970 Now I'm going to change the number of players to two and press play. 11:02.450 --> 11:03.230 Boom! 11:03.230 --> 11:05.000 We even knocked aura away. 11:05.000 --> 11:06.200 Pretty exciting. 11:06.200 --> 11:07.670 So that worked on the client. 11:07.670 --> 11:14.240 We can even play as client with a dedicated server, and it doesn't matter which of these we use. 11:17.630 --> 11:21.410 And we get our cues, so we're executing gameplay cues locally. 11:22.030 --> 11:29.590 And this is great because this does not result in any rpcs, as gameplay cues by default are multicast 11:29.590 --> 11:30.610 rpcs. 11:30.610 --> 11:35.140 And that can be really expensive bandwidth wise. 11:35.530 --> 11:39.820 If we're doing this a lot and this particular ability has 12. 11:40.380 --> 11:49.140 12 gameplay cues being executed, but they're executed locally, so no information is sent across the 11:49.140 --> 11:49.770 server. 11:49.770 --> 11:57.030 This is actually really useful, and we now know that the gameplay queue manager has static functions 11:57.030 --> 12:02.400 to execute these to make things easy for us, so use these when you can. 12:02.520 --> 12:06.570 If something's already replicated, use local gameplay cues. 12:06.570 --> 12:13.620 If something is already predicted with a gameplay ability, use local gameplay cues only in the situation 12:13.620 --> 12:18.690 where you're not already replicating something and you need that effect replicated. 12:18.690 --> 12:26.580 Do you want to use a replicated queue in all other cases where you can execute them locally? 12:27.860 --> 12:28.700 All right. 12:28.700 --> 12:30.890 That's going to conclude this video. 12:30.890 --> 12:32.060 Excellent job. 12:32.090 --> 12:40.160 You now have another tool in your tool belt to make your games more optimal, more performant and especially 12:40.160 --> 12:41.180 in multiplayer. 12:41.210 --> 12:42.230 Excellent job. 12:42.230 --> 12:43.400 And I'll see you soon.