WEBVTT 00:06.950 --> 00:07.850 Welcome. 00:07.850 --> 00:12.500 So we've been hearing a lot about gameplay effects, but we still haven't used them. 00:12.680 --> 00:17.630 We already know that we should be using gameplay effects to change our attribute values. 00:18.020 --> 00:22.730 It's now time to discuss what gameplay effects are and what they're capable of. 00:22.850 --> 00:28.310 Now they're capable of quite a lot and we'll touch on much of that in this lecture, but we're going 00:28.310 --> 00:32.330 to take things one step at a time in our project so we don't get overwhelmed. 00:32.360 --> 00:35.120 Remember, gas is a powerful system. 00:35.120 --> 00:37.730 It's important to take this step by step. 00:37.760 --> 00:43.880 This video is just an overview of some of the mini features of gameplay effects. 00:44.270 --> 00:46.760 So what is a gameplay effect? 00:46.940 --> 00:51.110 A gameplay effect is an object of type u gameplay effect. 00:51.140 --> 00:56.000 We use gameplay effects to change attributes and gameplay tags. 00:56.090 --> 01:02.660 Now we'll discuss what gameplay tags are a little later on when we start making some of our own. 01:02.690 --> 01:09.030 For now, it's just enough to understand that they can be used to identify by various things. 01:09.060 --> 01:13.710 Really, they're much more versatile than that, but we'll get to that now. 01:13.740 --> 01:16.140 Gameplay effects are data only. 01:16.140 --> 01:18.180 We don't add logic to them. 01:18.210 --> 01:22.230 We create a blueprint based on the new gameplay effect class. 01:22.260 --> 01:26.400 We don't subclass the gameplay effect into child classes. 01:26.430 --> 01:31.950 Gameplay effects change attributes through modifiers and executions. 01:32.070 --> 01:39.630 Modifiers come in various flavors, including more complex custom calculations for when attribute changes 01:39.630 --> 01:42.300 must be intricate and specific to gameplay. 01:42.300 --> 01:49.560 Design modifiers specify a type of operation to be performed on the attribute in question. 01:49.650 --> 01:58.620 These modifiers take a value which we refer to as a magnitude, and it uses that magnitude to change 01:58.620 --> 02:02.850 the attribute in a way that depends on the modifier operation. 02:02.880 --> 02:05.550 Here are the different types of operations. 02:05.700 --> 02:10.710 Add simply adds a given magnitude to the attributes value. 02:10.740 --> 02:15.750 You can add negative values here as well to get the effect of subtraction. 02:16.020 --> 02:18.810 Multiply multiplies the attribute. 02:18.840 --> 02:27.000 Divide divides it and override will replace the attributes value with the value provided for the magnitude. 02:27.570 --> 02:33.660 The magnitude used in these operations is produced from the magnitude calculation. 02:33.690 --> 02:37.440 Gameplay effects support several calculation types. 02:37.860 --> 02:41.820 Scalable float is the simplest type of modification. 02:41.850 --> 02:49.710 You can specify a hardcoded value for the magnitude directly, or you can use a table which scales the 02:49.710 --> 02:52.440 magnitude based on the gameplay effects level. 02:52.650 --> 02:56.010 You see, gameplay effects themselves can have their own levels. 02:56.040 --> 02:59.910 Attribute based uses another attributes value. 02:59.940 --> 03:05.970 For example, you can add a value to the player's health equal to the player's strength, for instance. 03:06.000 --> 03:10.110 Now there are options to customize this further. 03:10.110 --> 03:16.680 You could add to the player's health a value equal to strength times ten or something like that. 03:17.190 --> 03:21.410 Now, custom calculation class is another option. 03:21.420 --> 03:27.880 We can create a class designed to capture other values such as attributes or really any other variables 03:27.880 --> 03:33.410 that we want and use them in a calculation that can be arbitrarily complex. 03:33.430 --> 03:41.290 We typically call these modifier magnitude calculations or MKs, and these are a powerful way to change 03:41.290 --> 03:44.950 a single attribute based on a custom calculation. 03:45.340 --> 03:52.600 Another way to set the magnitude for the gameplay effect modifier is to use a set by color magnitude. 03:52.630 --> 03:54.940 This is a key value pair. 03:54.970 --> 03:59.590 Assigning a magnitude associated with a name or a gameplay tag. 03:59.590 --> 04:05.860 And this is useful if you need to set the modifiers magnitude based on code logic at the time that we 04:05.890 --> 04:09.130 create the gameplay effect or apply it. 04:09.370 --> 04:16.420 An even more powerful way to change an attributes value in the gameplay effect is to use a custom execution 04:16.420 --> 04:22.090 also known as a gameplay effect, execution calculation or exec calc. 04:22.120 --> 04:27.430 These can change more than one attribute and they can really do anything else that we choose to code 04:27.430 --> 04:27.970 in them. 04:27.970 --> 04:34.630 They're the most powerful way to modify attributes in a gameplay effect, and we'll learn more about 04:34.630 --> 04:36.610 all of these in time. 04:36.700 --> 04:40.090 Now gameplay effects have a duration policy. 04:40.300 --> 04:49.190 They can be either instant effects in which their modifier is applied instantly in a one off action. 04:49.210 --> 04:56.650 They can have a duration, meaning they can modify an attribute for a set period of time after which 04:56.650 --> 05:01.080 that modification is undone and they can be infinite. 05:01.090 --> 05:05.930 So they affect an attribute and that effect doesn't go away. 05:05.950 --> 05:08.370 Now, it's not that it never goes away. 05:08.380 --> 05:14.050 We can remove infinite effects, it's just that they stay until we manually remove them. 05:14.050 --> 05:20.740 So these are useful in situations where we may not know how long that effect should be applied and it 05:20.740 --> 05:23.710 should be removed in response to some gameplay. 05:23.740 --> 05:30.550 Gameplay effects can stack and they have their own policies for how to stack and of course they can 05:30.550 --> 05:32.190 add gameplay tags. 05:32.200 --> 05:33.970 They can also grant abilities. 05:33.970 --> 05:36.970 And these are just a few things the gameplay effects can do. 05:36.970 --> 05:40.750 So they're actually a lot more versatile than all of these things. 05:40.780 --> 05:47.800 Now gameplay effects can be applied directly, but usually we create a more lightweight version of them 05:47.800 --> 05:50.620 known as a gameplay effect spec. 05:50.650 --> 05:56.570 This concept of a spec is common in gas and is a form of optimization. 05:56.590 --> 06:03.520 The spec contains the bare bones information needed to perform the modifications and the only actual 06:03.520 --> 06:10.150 instance of the gameplay effect class that typically gets instantiated is the class default object or 06:10.150 --> 06:10.910 CDO. 06:10.930 --> 06:13.240 Now that's just how it typically occurs. 06:13.240 --> 06:17.860 Most of the things we're covering here are just ways that it's typically done. 06:17.890 --> 06:25.500 The gameplay effect class is just versatile enough to never need to be subclassed into child classes. 06:25.510 --> 06:33.070 If you need complex attribute modifications, you use custom executions or magnitude calculations rather 06:33.070 --> 06:36.600 than subclassing the gameplay effect into a child class. 06:36.610 --> 06:42.910 The effect spec carries information with it as well, such as gameplay tags that the effect has, and 06:42.910 --> 06:49.150 it also has an effect context an additional class that can store more information about the effects 06:49.150 --> 06:50.260 being applied. 06:50.290 --> 06:56.830 References to the causer and the target of the effect are easily accessed and can be used to determine 06:56.830 --> 07:02.800 what happens to the overall magnitude calculation, as well as trigger gameplay mechanics to any actors 07:02.800 --> 07:04.210 involved in the effect. 07:04.210 --> 07:09.510 So as you can see, gameplay effects are quite versatile and very customizable. 07:09.520 --> 07:14.980 They were designed to meet just about any need you may have when it comes to affecting a player's attributes 07:14.980 --> 07:15.830 in the game. 07:15.850 --> 07:21.220 Gameplay effects are often applied from within gameplay abilities, but they don't have to be. 07:21.220 --> 07:27.130 An actor may have a gameplay effect that it wishes to apply to some other actor that overlaps with it. 07:27.420 --> 07:31.440 This is a nice simple example, and it's what we'll start with. 07:31.470 --> 07:34.120 Remember our aura effect actor? 07:34.140 --> 07:40.230 We're going to return to this class and make it quite a bit more useful, and we'll do that next. 07:40.350 --> 07:41.460 I'll see you soon.