WEBVTT 00:00.670 --> 00:03.290 Welcome to your next quest. 00:03.310 --> 00:09.990 In this quest, I'd like you to replace the callbacks in our overlay widget controller with Lambdas. 00:10.000 --> 00:16.510 So we have some callbacks for when our attributes change and we're binding those to delegates on the 00:16.510 --> 00:18.130 ability system component. 00:18.250 --> 00:25.840 But I'd like you to actually get rid of those callbacks and instead use lambdas inside of which you're 00:25.840 --> 00:29.240 going to make those delegate broadcasts to the widgets. 00:29.260 --> 00:33.100 So pause the video and conquer this challenge now. 00:36.290 --> 00:36.800 Okay. 00:36.800 --> 00:42.680 So for this quest, we're going to replace some callbacks in the overlay widget controller. 00:43.040 --> 00:47.090 I don't really need gameplay tag container, so I'm going to close those files. 00:47.090 --> 00:51.740 And here we have our callbacks health change, Max, health changed and so on. 00:51.740 --> 00:59.050 And all these functions are doing is broadcasting some values with our delegates. 00:59.060 --> 01:07.100 And by the way, I'm noticing something right here my on max health changed is an on health change signature, 01:07.100 --> 01:09.410 not an on max health change signature. 01:09.440 --> 01:16.070 Something from copy pasting, I think so I'm going to take my on max health change signature and just 01:16.070 --> 01:17.210 replace that there. 01:17.240 --> 01:23.420 Now the reason it still worked is because this is a separate variable than this and they're both just 01:23.420 --> 01:26.630 delegates that can broadcast a float. 01:26.630 --> 01:34.760 So really there's no reason that we can't use the same delegate for all of our attributes and just create 01:34.760 --> 01:38.520 a new variable of that same type for each one. 01:38.520 --> 01:41.460 So maybe we'll refactor that here as well. 01:41.460 --> 01:49.230 But for the task at hand, we need to get rid of these delegates and replace them with lambdas. 01:49.260 --> 01:53.010 Now, the most important thing here is that our lambda has the correct signature. 01:53.010 --> 01:57.030 Otherwise it can't bind to a delegate that requires this signature. 01:57.030 --> 02:05.850 And that's a function signature with an input parameter of const reference to on attribute change data. 02:05.910 --> 02:12.720 So I'm just going to copy that input parameter and I'm going to come back up to where we are binding 02:12.720 --> 02:14.520 callbacks to these delegates. 02:14.610 --> 02:17.010 And I'm going to start with the health. 02:17.010 --> 02:24.240 And all we need to do here is instead of calling Add new object, we're going to call add lambda instead. 02:24.240 --> 02:28.770 And the lambda goes right here inside of the parentheses. 02:28.770 --> 02:34.980 So I'm going to put those each on new lines so we can put the lambda right here in between. 02:35.340 --> 02:42.930 Now it's going to have square brackets, it's going to have parentheses and it's going to have a body. 02:42.930 --> 02:49.020 And in the parentheses that's where we put what I copied, the const reference called data. 02:49.020 --> 02:55.860 And I'm going to put the body on a new line so we can see the scope of this lambdas body quite easily. 02:55.860 --> 02:58.380 And down here to health change. 02:58.380 --> 03:02.970 All I want to do is broadcast my on health changed delegate. 03:02.970 --> 03:04.340 So I'm going to paste that in. 03:04.350 --> 03:08.790 Now of course I get the red squiggles because it says this is not captured. 03:08.790 --> 03:14.520 Remember, the capture goes into the square brackets and we can capture this and that's going to take 03:14.520 --> 03:15.150 care of it. 03:15.150 --> 03:21.330 Now the cool thing is, while, yes, I put these all on a bunch of different lines, this is all very 03:21.330 --> 03:21.930 compact. 03:21.930 --> 03:26.940 We could put this all on a single line and keep this really nice and neat if we want. 03:26.970 --> 03:29.130 Here's what it looks like if you do that. 03:30.140 --> 03:32.960 We'll just go ahead and delete the empty space. 03:35.300 --> 03:36.350 Like so. 03:37.310 --> 03:42.000 And one more thing that closing parentheses there. 03:42.020 --> 03:44.600 So here's what it looks like on a single line. 03:44.630 --> 03:50.030 Now, as you can see, we have quite a few tokens just bunched up. 03:50.030 --> 03:52.100 So I prefer not to do that. 03:52.100 --> 03:53.600 But if you wanted to, you could. 03:53.630 --> 03:58.700 So I'm going to hit Control Z a few times until it gets back to how it was. 03:59.300 --> 04:01.250 And I think that's it. 04:01.340 --> 04:02.390 So we're good. 04:02.690 --> 04:07.010 And now our callback health changed is obsolete. 04:07.040 --> 04:08.070 We don't need it. 04:08.090 --> 04:09.350 I'm going to remove it. 04:10.500 --> 04:12.810 And I'll remove it from here as well. 04:12.960 --> 04:17.080 So this is a nice way to clean up our widget controller. 04:17.100 --> 04:17.940 Right. 04:18.150 --> 04:21.980 So we can do the same thing for our maxhealth. 04:21.990 --> 04:28.750 So I can copy this being extremely careful because copy and paste can be dangerous. 04:28.770 --> 04:31.250 So we're going to go through the entire line. 04:31.260 --> 04:33.630 We see that we're getting the health attribute. 04:33.660 --> 04:39.000 We want to get max health attribute and we're adding a lambda. 04:39.090 --> 04:44.910 And what we want to broadcast is on max health changed like so. 04:45.030 --> 04:50.490 So we're done with this one and we're done with Max health changed. 04:50.520 --> 04:55.140 We don't need that and we don't need the declaration as well. 04:55.260 --> 04:56.460 We'll delete that. 04:56.820 --> 05:01.500 Okay, so two more we want manage changed and Max manage changed. 05:01.620 --> 05:10.200 So I'm going to copy this and we have to change the getter for the attribute we want get mana attribute 05:10.300 --> 05:12.610 and we want to change the delegate. 05:12.640 --> 05:14.710 We want on mana changed. 05:14.710 --> 05:16.270 And then last one. 05:18.400 --> 05:28.030 It's going to be get max mana attribute and on max Mana changed and we can get rid of these lines where 05:28.030 --> 05:34.960 we're binding callbacks instead we're now binding lambdas and we can get rid of these callback functions 05:34.960 --> 05:37.600 altogether so we'll get rid of them. 05:39.550 --> 05:44.110 Okay, so we've just reduced the amount of code quite a bit. 05:44.110 --> 05:49.620 And again, we could make this four lines of code right here if we wanted to. 05:49.630 --> 05:55.990 It doesn't have to take up this much space, but I prefer to be able to kind of see what's going on. 05:55.990 --> 05:57.730 So I'm going to leave it like that. 05:57.730 --> 06:01.750 And now we see that thanks to Lambdas, we don't need callbacks. 06:01.750 --> 06:06.520 We can just make an anonymous function that broadcasts a delegate for us. 06:06.550 --> 06:07.690 This is kind of nice. 06:07.690 --> 06:11.860 It's a little bit cleaner and I prefer this way for a lot of things. 06:11.860 --> 06:14.740 And that concludes the challenge. 06:14.740 --> 06:21.290 Now, before we wrap up, though, I'm going to go back to this issue where we have four delegates that 06:21.290 --> 06:22.850 are essentially identical. 06:22.880 --> 06:25.370 The only thing that's different is their names. 06:25.370 --> 06:32.240 And down here, we're creating one of each kind to broadcast an attribute value. 06:32.240 --> 06:38.540 And really, because these are all functionally identical, we don't really need a delegate for each 06:38.570 --> 06:39.470 attribute. 06:39.470 --> 06:43.040 In fact, this project is going to have more attributes. 06:43.040 --> 06:45.260 They're going to grow in number. 06:45.410 --> 06:50.150 So really, we don't need to declare a new delegate each time. 06:50.150 --> 06:52.280 We can just use a single delegate. 06:52.280 --> 06:54.770 In fact, I'm going to declare one here. 06:54.770 --> 07:01.970 It's going to be called F on attribute changed signature. 07:02.440 --> 07:10.600 And we'll call this float new value and then we can just have one of these for each of these instead 07:10.600 --> 07:13.200 of each of them being a different type. 07:13.210 --> 07:17.290 Each of these can all be the on attribute changed signature. 07:17.290 --> 07:22.720 We can change them all to this and we can come back here and delete these four declarations. 07:22.720 --> 07:27.340 And now we just have a single delegate capable of broadcasting a float. 07:27.340 --> 07:31.780 That's all we care about our delegate being able to do. 07:31.780 --> 07:36.820 And for some reason I think I've deleted a semicolon down here. 07:36.820 --> 07:38.050 So I'm going to fix that. 07:38.050 --> 07:44.350 And with that, I should make sure this all compiles because we've made quite a few changes here. 07:44.350 --> 07:53.440 So compiling and the build succeeds because all of these broadcasts just take floats and they work. 07:53.590 --> 07:59.680 But we're going to want to play test because when you make this many changes, you should really test 07:59.680 --> 08:00.220 out your work. 08:00.220 --> 08:05.360 But before we do take a look, our widget controller looks a lot better. 08:05.390 --> 08:06.710 It's a lot cleaner. 08:06.710 --> 08:10.880 We have less delegate declarations and we have less functions. 08:10.880 --> 08:13.940 In fact, we have no callbacks at all. 08:13.970 --> 08:15.890 We just bind lambdas. 08:15.890 --> 08:16.820 So that's cool. 08:16.820 --> 08:20.000 Let's hit the debug button and test it out. 08:21.280 --> 08:22.090 All right. 08:22.090 --> 08:28.990 So I'm going to press play, and pressing play is a good way to find out if we have some errors in the 08:28.990 --> 08:29.930 blueprints. 08:29.950 --> 08:36.130 I'm going to open all errored blueprints and my message log gives me links to where those errors are. 08:36.160 --> 08:38.710 I'm going to click on the one for Health Globe. 08:38.710 --> 08:43.270 And really, it's just because our delegate has changed. 08:43.300 --> 08:49.600 All I need to do is right click and refresh nodes and make sure that those connections aren't broken. 08:51.620 --> 08:55.160 And I have another one down here on Maxhealth changed. 08:55.190 --> 08:57.500 We can refresh the nodes here. 08:58.710 --> 09:00.030 And hook that up. 09:00.910 --> 09:02.860 Compile again, and we're good. 09:02.920 --> 09:04.240 Now that's the health globe. 09:04.240 --> 09:07.170 Let's go to the Mana Globe and compile here. 09:07.180 --> 09:10.960 Actually, I see the two errors, refresh nodes here and hook up. 09:10.960 --> 09:12.700 Refresh nodes here. 09:13.530 --> 09:14.700 And hook up. 09:15.940 --> 09:19.660 Compile and we're good and we just need to play test. 09:19.660 --> 09:24.490 I'm going to save all and then test and pick up mana. 09:25.680 --> 09:27.630 We're getting Mana looks good. 09:27.630 --> 09:28.890 Let's pick up health. 09:28.890 --> 09:30.240 We're getting health. 09:31.060 --> 09:32.500 Looks great. 09:34.160 --> 09:35.420 And everything works. 09:35.420 --> 09:36.200 Excellent. 09:36.200 --> 09:37.940 So awesome job. 09:38.030 --> 09:40.400 I'm proud of you for tackling the challenge. 09:40.400 --> 09:44.000 It was a pretty good one and I'll see you in the next video.