WEBVTT 00:06.950 --> 00:08.080 Welcome back. 00:08.090 --> 00:15.860 Now, we had our game plan for experience and we're up to the point where we need to reward experience 00:15.860 --> 00:16.730 points. 00:16.910 --> 00:22.970 So basically we need an amount of XP that each enemy gives based on its level and class. 00:23.150 --> 00:27.590 And we also need to actually award XP when killing an enemy. 00:27.710 --> 00:31.790 Now, once we've gotten that handled, we can handle leveling up. 00:31.790 --> 00:35.660 But first we need to handle actually gaining experience. 00:35.870 --> 00:39.830 So this is a system that we're going to need to put some thought into. 00:39.830 --> 00:46.130 And in order to put some thought into it, let's just walk through the process of what happens when 00:46.130 --> 00:50.270 a player gains experience, specifically when it comes to combat. 00:50.480 --> 00:57.290 So we'll have a player, let's say they're controlling some pawn or character and that character attacks 00:57.290 --> 00:58.100 an enemy. 00:58.280 --> 01:02.780 Now, when this happens, typically the enemy will take some damage. 01:03.420 --> 01:10.950 And this act of taking damage is going to trigger a response in the attribute set as they've just received 01:10.950 --> 01:11.770 damage. 01:11.790 --> 01:18.360 The damage meta attribute is going to trigger a response, at which point the attribute set decides 01:18.360 --> 01:19.320 what happens. 01:19.320 --> 01:24.270 And the attribute set knows at this point whether this damage was fatal or not. 01:24.360 --> 01:26.400 Now we need to gain experience. 01:26.400 --> 01:33.810 If the damage was fatal, we've just slain an enemy, which means the enemy needs an amount of experience 01:33.810 --> 01:36.210 to reward the attacker with. 01:36.240 --> 01:40.410 So we already knew that that was a crucial part of all this. 01:40.410 --> 01:48.570 But at this point, the attribute set needs to know how much experience to award and for that matter, 01:48.570 --> 01:50.910 how to award that experience. 01:51.060 --> 01:56.960 Now we know that we can wait for gameplay events and we can send gameplay events to actors. 01:56.970 --> 02:04.180 If our attribute set knows that this damage was fatal and knows how much experience to give to the attacker, 02:04.180 --> 02:09.340 it can send a gameplay event and send that reward value along with it. 02:09.370 --> 02:15.700 Now if we're sending a gameplay event to the attacker, the attacker needs to be able to receive it. 02:15.940 --> 02:22.390 Now we can receive gameplay events if we have some kind of gameplay ability that's waiting for one. 02:22.480 --> 02:24.820 So we can create a gameplay ability. 02:24.850 --> 02:30.700 This can be a passive gameplay ability in a sense that we can activate it at the beginning of the game 02:30.700 --> 02:33.380 and keep it active throughout the game. 02:33.400 --> 02:41.230 We can call this listen for events and this gameplay ability can use wait gameplay event to wait for 02:41.230 --> 02:47.590 any gameplay events that get sent its way and as soon as it receives a gameplay event it can then get 02:47.590 --> 02:50.410 that XP reward and do something with it. 02:50.440 --> 02:53.830 Now what can we do with the XP reward? 02:54.130 --> 03:03.040 Well, our XP is on the player state and we chose not to make it an attribute, but it would be very 03:03.040 --> 03:11.080 convenient if attribute sets could respond to changes in incoming experience points so that it could 03:11.080 --> 03:12.310 act accordingly. 03:12.340 --> 03:19.660 So if we could create a gameplay effect and make a gameplay effect spec that can carry that XP reward, 03:19.690 --> 03:26.020 we can apply that to the self to the ability system component that owns this gameplay ability. 03:26.170 --> 03:32.380 Now if we're using gameplay effects, those are meant to affect attributes, right? 03:32.380 --> 03:36.070 But we chose not to make our XP an attribute. 03:36.100 --> 03:39.040 Rather it's a variable on the player state. 03:39.040 --> 03:42.400 But that doesn't mean that we can't set some kind of attribute. 03:42.430 --> 03:48.340 This is actually a great example of when to use a meta attribute, just like our incoming damage meta 03:48.340 --> 03:49.150 attribute. 03:49.180 --> 03:51.760 This is an attribute that gets consumed. 03:51.760 --> 03:55.660 It's zeroed out and then used to change something. 03:55.900 --> 04:04.360 So if we're setting this incoming XP attribute on the attacker, then its own attribute set can then 04:04.360 --> 04:08.350 add to the XP on the attacker's player state. 04:08.380 --> 04:14.410 Now this can be done through an interface or any other way that we see fit, but this is how the player 04:14.410 --> 04:21.640 state can then get its XP increased and once that happens, the player state will in turn broadcast 04:21.640 --> 04:28.510 its delegate to the widget controller that's responsible for updating widgets such as the XP bar. 04:28.690 --> 04:35.710 So as you can see in an RPG game involving experience, we have a number of moving parts that we need 04:35.710 --> 04:36.730 to set up here. 04:36.730 --> 04:40.660 So for our next steps forward, we have another game plan. 04:40.750 --> 04:45.910 We first need an XP reward on our enemies and a way to get it. 04:45.910 --> 04:49.270 So this could be a variable on the enemy class. 04:49.270 --> 04:56.050 But then we should create some kind of access or function probably on the enemy interface that we can 04:56.050 --> 04:57.100 easily get. 04:57.130 --> 05:04.540 Then after that we need a meta attribute for incoming XP and this is so that we can respond to things 05:04.540 --> 05:06.340 in the attributes set. 05:06.760 --> 05:11.430 Now we're also going to create a gameplay ability that will be passive. 05:11.440 --> 05:17.590 We can call this listen for events and granted in the beginning of the game and this can be something 05:17.590 --> 05:19.300 that we never deactivate. 05:19.300 --> 05:22.390 It's just always going, listening for events. 05:22.390 --> 05:29.620 And as soon as it receives an event with a specific set of data perhaps identified by a gameplay tag, 05:29.620 --> 05:36.510 then it can apply a gameplay effect in response to that event setting that incoming XP. 05:36.880 --> 05:42.430 Now we also need to award the XP and the attribute set whenever the damage is fatal. 05:42.430 --> 05:50.110 So for enemies taking damage as soon as they've taken fatal damage, we need to award the XP by sending 05:50.110 --> 05:57.040 that gameplay event and we also need to handle that incoming XP and the attribute set and increase the 05:57.040 --> 05:58.660 XP on the player state. 05:58.660 --> 06:04.300 So the attribute set will be responsible for changes to XP and two capacities. 06:04.430 --> 06:13.790 One is sending a gameplay event when damage is fatal and two is handling the incoming XP meta attribute 06:13.790 --> 06:17.210 and increasing the real XP on the player state. 06:17.240 --> 06:24.140 Once we've tied all this together, then when slaying an enemy which has its own XP amount, we should 06:24.140 --> 06:27.260 see XP increase on the XP bar. 06:27.260 --> 06:34.280 But most importantly we'll have our XP kept track of and the next step will be handling the situation 06:34.280 --> 06:42.800 when XP rises above that level up requirement for the current level where we can increase the player's 06:42.800 --> 06:45.680 level and reward them for leveling up. 06:45.830 --> 06:50.840 So now that we know the steps forward, let's continue in the next video.