WEBVTT 00:06.980 --> 00:07.940 Welcome. 00:07.940 --> 00:11.240 In this section, we're going to start using gameplay tags. 00:11.270 --> 00:18.350 Gameplay tags are essential in gas, though they do exist outside of gas and can be used in non gas 00:18.350 --> 00:19.700 projects too. 00:19.970 --> 00:23.030 But in gas we use them extensively. 00:23.030 --> 00:24.800 So what are they? 00:24.830 --> 00:28.070 Gameplay tags are basically names. 00:28.340 --> 00:34.700 They have the type of gameplay tag and they're registered with the gameplay tag manager. 00:34.730 --> 00:37.970 Gameplay tags are hierarchical in nature. 00:38.000 --> 00:45.710 They take the form of parent child grandchild where each level of the hierarchy is separated by a dot. 00:45.740 --> 00:49.430 They don't have to have a three level hierarchy like this example. 00:49.430 --> 00:51.430 They can have more or less. 00:51.440 --> 00:54.740 So why are gameplay tags so great? 00:54.770 --> 01:01.430 Can't we just use an f string or f name or maybe an enum or just booleans in some cases? 01:01.550 --> 01:06.110 Well, tags come with a number of inherent qualities that make them versatile. 01:06.140 --> 01:12.390 Yes, they seem a lot like strings or F names, and in fact they are f names at the core. 01:12.420 --> 01:19.800 They have a member variable called tag name, which is indeed an F name, but their hierarchical nature 01:19.800 --> 01:24.300 makes them useful tools when it comes to making our code more flexible. 01:24.600 --> 01:31.080 Two tags can be compared for exact equality or even partial equality. 01:31.110 --> 01:36.540 Maybe they share the same root tag names only and that might be significant in code. 01:36.570 --> 01:43.170 The gameplay ability system is designed to use gameplay tags in just about every single class. 01:43.170 --> 01:48.180 In the API, we have the concept of giving tags to actors. 01:48.300 --> 01:53.940 What we mean by that is that we're giving the tag to an actor's ability system component. 01:54.240 --> 01:58.500 We then say that that ability system component has that tag. 01:58.500 --> 02:04.740 The ability system component implements an interface called the gameplay tag asset interface. 02:04.830 --> 02:12.570 This interface has a number of functions that make it easy to look at all owned tags, see if a particular 02:12.570 --> 02:20.220 tag is owned, or get all tags that match a given tag, or even see if any of the owned tags match a 02:20.220 --> 02:21.570 specified tag. 02:21.690 --> 02:27.180 Since these are interface functions, any class can implement this interface and decide how to handle 02:27.180 --> 02:28.320 these operations. 02:28.320 --> 02:34.470 Although the ability system component handles these in its own way, since classes can have multiple 02:34.470 --> 02:39.810 gameplay tags, we naturally need to store them in some sort of container. 02:39.960 --> 02:43.260 Now we don't use arrays to store our gameplay tags. 02:43.260 --> 02:50.010 Instead we use the gameplay tag container, which has some gameplay tag specific functionality and some 02:50.040 --> 02:51.390 added efficiency. 02:51.420 --> 02:58.890 Gameplay tag containers have the concept of a tag map count, meaning you can have more than one instance 02:58.890 --> 03:01.080 of a single tag in the container. 03:01.080 --> 03:08.340 It's this tag map count that tells us how many of a given tag exists in the container and at times this 03:08.340 --> 03:14.460 could be zero depending on whether a tag has been added and then subsequently removed, for example. 03:14.670 --> 03:21.870 So in debug mode, for example, we might see a given tag in the container even though its tag map count 03:21.870 --> 03:22.740 is zero. 03:22.740 --> 03:24.720 So that's something to be aware of. 03:24.930 --> 03:33.390 But all of these functions that check to see if a given object has a tag and its tag container are equipped 03:33.390 --> 03:35.100 to handle that situation. 03:35.100 --> 03:38.700 So it's the tag map count that they check for a given tag. 03:38.970 --> 03:43.200 Various classes and gas can have and use gameplay tags. 03:43.440 --> 03:49.920 Gameplay effects, for example, can contain tags that they grant to the ability system component. 03:49.920 --> 03:51.300 They're being applied to. 03:51.330 --> 03:57.750 Say we have an actor that applies a gameplay effect to a given ability system component. 03:57.750 --> 04:02.070 For this example, we'll say that this is a duration based effect. 04:02.340 --> 04:08.580 Now this gameplay effect can have a certain tag that it grants to the ability system component upon 04:08.580 --> 04:09.720 application on. 04:09.720 --> 04:17.190 Now that ability system component has that tag when the effects duration expires and it removes itself, 04:17.190 --> 04:19.590 it removes the tag as well. 04:19.770 --> 04:23.250 Gameplay effects are designed to handle that. 04:23.280 --> 04:26.400 Now in gas, this is actually quite significant. 04:26.430 --> 04:29.160 Many operations depend on tags. 04:29.160 --> 04:33.990 For example, an ability system component might have some gameplay ability. 04:34.230 --> 04:34.770 Now. 04:34.770 --> 04:41.070 Yes, we haven't learned about abilities yet, but let's just say that it has an ability that it wants 04:41.070 --> 04:42.090 to apply. 04:42.540 --> 04:43.140 Now. 04:43.140 --> 04:49.560 This gameplay ability may have a blocked tag, meaning that if the ability system component has that 04:49.560 --> 04:54.510 tag and it attempts to activate the ability, it will not be able to do so. 04:54.510 --> 05:02.730 It's blocked because it has the blocked tag or an ability system component may have an ability which 05:02.730 --> 05:06.600 contains a list of required tags, in other words. 05:06.720 --> 05:13.800 The ability system component must have these tags to activate the ability, and if it attempts to activate 05:13.800 --> 05:19.060 the ability, it will not be able to do so as it doesn't meet those tag requirements. 05:19.080 --> 05:22.080 It must have those tags to activate the ability. 05:22.470 --> 05:29.310 These are just a couple of examples of built in capabilities that work with tags, but tags can be used 05:29.310 --> 05:30.400 for other things. 05:30.420 --> 05:39.720 We can use them to identify inputs, abilities, attributes, damage types, buffs and debuffs messages, 05:39.720 --> 05:43.460 any type of data or really anything else we can think of. 05:43.470 --> 05:49.230 So we'll be making extensive use of gameplay tags all throughout this course, and we'll first begin 05:49.230 --> 05:51.810 by learning how to add them to our project. 05:51.810 --> 05:53.310 So we'll do that next. 05:54.090 --> 05:55.110 I'll see you soon.