WEBVTT 00:06.860 --> 00:08.090 Welcome back. 00:08.240 --> 00:12.980 Now let's go back to our data table we just created in blueprints. 00:13.010 --> 00:14.570 UI data. 00:14.600 --> 00:15.590 Here it is. 00:15.620 --> 00:19.490 And we added one row, but we didn't fill anything out. 00:19.490 --> 00:23.840 But we did add four new gameplay tags to our project. 00:23.960 --> 00:27.920 So for this first row, I'm going to set my message tag. 00:27.920 --> 00:31.520 We have our messages and I'm going to set it to health crystal. 00:31.760 --> 00:39.680 Now when we look up Rose to find a specific row in a data table, we can look them up by name. 00:39.830 --> 00:45.680 So for my row name, I'm going to have the same name as my message tag. 00:45.680 --> 00:52.790 So I'm going to double click on new row here and call this message dot Health Crystal. 00:54.020 --> 00:56.180 And we're going to look this up by name. 00:56.270 --> 01:02.450 Now, this method is a little bit error prone because you can have typos here, but as long as you type 01:02.450 --> 01:04.720 it correctly, you should be fine. 01:04.730 --> 01:11.190 For this reason, I often like to use data assets instead of data tables and we'll be using data assets 01:11.190 --> 01:12.780 throughout the course as well. 01:12.780 --> 01:18.120 But I think it's good to know how to use both data assets and data tables. 01:18.120 --> 01:21.870 And we're going to use a data table for this particular application. 01:22.170 --> 01:24.120 So we have a message tag. 01:24.120 --> 01:25.800 We can also have a message. 01:25.800 --> 01:30.240 And for my health, Crystal, I'm going to have the message picked up. 01:30.240 --> 01:32.580 Health Crystal. 01:33.940 --> 01:36.640 Now, we don't have a message widget just yet. 01:36.670 --> 01:40.240 We still need to make one of those, but we can choose an image. 01:40.240 --> 01:48.310 And in our project, if we search for t underscore health, we have a t health crystal. 01:48.310 --> 01:51.820 And if I browse to it, it's in this UI pickups. 01:52.030 --> 01:55.000 So now our image has the health crystal. 01:55.030 --> 01:57.520 The only thing missing is the message widget. 01:57.640 --> 01:59.830 So we're going to want to make that. 01:59.890 --> 02:04.640 But until we've got that, we can add the rest of these rows. 02:04.660 --> 02:05.860 I'd like four rows. 02:05.860 --> 02:07.210 I'm going to add another one. 02:07.210 --> 02:12.160 And for this next one, I'm going to go to message and choose Health Potion. 02:12.280 --> 02:15.700 And this row will have the same name as the tag. 02:15.700 --> 02:27.310 So message dot health potion and our message will be picked up a health potion. 02:27.550 --> 02:34.850 And for this image, I'm going to search for t underscore potion and I'm going to find t potion red. 02:34.950 --> 02:37.060 That will be the texture. 02:37.070 --> 02:38.750 So I'll do this two more times. 02:38.750 --> 02:40.040 I'll click add. 02:40.040 --> 02:42.650 And for this one we're going to choose the message. 02:42.650 --> 02:45.770 Tag message Manna Crystal. 02:45.950 --> 02:50.720 I'm going to name the row message dot manna crystal. 02:51.920 --> 02:54.890 I'm going to put the message into the text box. 02:54.890 --> 03:03.800 Picked up a manna crystal and for the image, I'm going to search for Manna Crystal and choose that 03:03.800 --> 03:04.620 texture. 03:04.640 --> 03:11.720 And finally, one more and we'll give this row the tag message manna potion. 03:11.720 --> 03:15.860 We'll name the row message dot manna potion. 03:16.940 --> 03:18.980 I'll give it a texture. 03:19.010 --> 03:28.010 I'll search for T potion blue and for the message I will say picked up manna potion. 03:28.960 --> 03:31.060 Or picked up a mana potion. 03:31.060 --> 03:33.850 I don't know how I worded the others. 03:33.970 --> 03:35.170 Picked up health. 03:35.170 --> 03:38.120 Crystal picked up a health potion. 03:38.140 --> 03:45.850 Let's just say a in all of them picked up a health crystal, a mana potion, picked up a mana crystal 03:45.850 --> 03:47.140 picked up a mana potion. 03:47.140 --> 03:48.160 That looks good. 03:49.210 --> 03:55.870 Okay, so there's data in all four of the rows and the row name is the same as the tag. 03:55.870 --> 03:58.660 So we'll be looking things up by name. 03:58.780 --> 04:02.270 So now that we have four rows, this is great. 04:02.290 --> 04:07.120 I'd like to be able to look these up in our lambda in C plus plus. 04:07.120 --> 04:12.940 But before we do that, I want our gameplay effects to each have these message tags. 04:12.940 --> 04:21.760 So what I'm going to do is go into the blueprints folder into actor, and then we have Crystal and Potion. 04:21.760 --> 04:25.570 We'll go into potion first and Open G potion Heal. 04:25.570 --> 04:28.880 Now we added to the gameplay effect assets tags. 04:28.880 --> 04:32.120 That's what we're sending over to the widget controller. 04:32.120 --> 04:36.250 But we just added some tags that we had just because we had them. 04:36.260 --> 04:42.560 I'm going to clear all and if I compile you'll see that removes it completely and I'll add to the added 04:42.590 --> 04:43.610 tags. 04:43.820 --> 04:47.540 We're going to go message and this is G potion heal. 04:47.540 --> 04:50.570 So I'm going to choose message Health potion. 04:51.840 --> 04:54.990 And if I compile, it goes up to the combined tags. 04:54.990 --> 04:59.750 So we can save that and I can open potion mana. 04:59.760 --> 05:01.260 I'm going to clear all. 05:01.680 --> 05:08.850 And then for the added tags, I'm going to add message mana potion, compile and save, and then I can 05:08.850 --> 05:15.090 go into my crystal folder and tag crystal heal and clear all I don't need to compile. 05:15.090 --> 05:21.390 I was just doing that to show that combine tags will be updated, but I'm going to add to the added 05:21.420 --> 05:21.840 tags. 05:21.840 --> 05:26.520 This is crystal heal, so I'm going to choose message health crystal. 05:26.520 --> 05:29.760 If I compile, you'll see that the old tag is gone. 05:29.760 --> 05:36.150 The new tag is there and if I open Crystal Mana, it looks like I have nothing here. 05:36.150 --> 05:43.530 I'm going to add to the added tags message mana crystal compile and we can even test this by pressing 05:43.530 --> 05:46.980 play and picking up some crystals and some potions. 05:46.980 --> 05:51.390 And we'll see that we get those message tags because we're receiving those. 05:51.390 --> 05:53.110 So we know that that's working. 05:53.110 --> 05:55.360 Everything's looking good on that front. 05:55.360 --> 06:03.010 So we're done in the editor for now, I'm going to save all and close and we need the ability to look 06:03.010 --> 06:07.660 up the correct row in our message widget data table. 06:07.690 --> 06:12.340 Now, I'm only concerned right now with the overlay widget controller, so I'm going to right click 06:12.340 --> 06:20.230 on the header file, close other tabs and then open the CPP with alt o or control k o. 06:20.260 --> 06:24.250 And I'm back here in the CPP file. 06:24.280 --> 06:29.230 Now we're still just in bind callbacks to dependencies right here in our lambda. 06:29.260 --> 06:36.670 All we're doing is receiving the gameplay tag container that contains our asset tags for any effect 06:36.670 --> 06:38.440 that has just been applied. 06:38.440 --> 06:40.990 And we're printing a message to the screen. 06:40.990 --> 06:42.190 That's all we're doing. 06:42.190 --> 06:47.980 But now I'd like to make a lookup in our widget data table. 06:47.980 --> 06:49.630 So how are we going to do that? 06:49.630 --> 06:58.570 Well, I'd like to be able to find the data table row that corresponds to the gameplay tag, right? 06:58.570 --> 07:04.750 This tag here as we're looping through all the tags in this gameplay tag container called asset tags, 07:04.870 --> 07:11.290 I'd like to be able to take a data table and a gameplay tag and return the row. 07:11.410 --> 07:19.270 So to do that I'd like a function, but I'd like this function to be sort of versatile. 07:19.270 --> 07:28.990 I'd like it to be able to return any sort of row, any sort of data table row by just taking in a generic 07:28.990 --> 07:31.300 data table and a gameplay tag. 07:31.300 --> 07:32.860 So let's make that function. 07:32.860 --> 07:40.630 I'll go back to the header file and in the protected section I'm going to make a really nice generic 07:40.630 --> 07:46.780 function and the return type is going to be a data table row. 07:46.780 --> 07:51.400 But I'd like this function to be able to return any type of data table row. 07:51.400 --> 08:00.370 So I'm going to have the return type be t star, in other words, a pointer to type T, How can I do 08:00.370 --> 08:00.610 that? 08:00.610 --> 08:02.710 Well, this is going to be a template. 08:02.740 --> 08:12.220 So template function we use template with angle brackets and we say type name followed by T and T is 08:12.220 --> 08:15.580 going to be our type parameter. 08:15.580 --> 08:22.480 In other words, this function can be called with any type and this function will be called get data 08:22.480 --> 08:26.080 table row by tag. 08:26.140 --> 08:32.650 And I'd like to be able to pass in a new data table that will be my pointer. 08:32.650 --> 08:40.630 We'll call this data table I'd like to pass in a const gameplay tag reference called Tag. 08:41.350 --> 08:48.280 So we have a template function here and it's going to take in a data table and a tag. 08:48.310 --> 08:51.070 Find the row and return that row. 08:51.920 --> 08:53.720 So let's generate a definition. 08:53.720 --> 09:01.400 And if I let writer do it for me, it's going to make this definition right here inside the header file, 09:01.490 --> 09:03.920 which is pretty common for template functions. 09:03.920 --> 09:08.330 In fact, some compilers won't let you put it in the CPP file at all. 09:08.540 --> 09:14.930 Some compilers are smart enough to look in there, but we're going to keep it right here and Visual 09:14.930 --> 09:16.910 Studio should do the same. 09:16.910 --> 09:24.800 And when you have the function definition, notice we still have template type name above it that's 09:24.800 --> 09:32.720 required for template functions and this function is going to be designed to find a data table and return 09:32.720 --> 09:34.940 the row no matter what the row type is. 09:35.180 --> 09:35.990 Right? 09:35.990 --> 09:42.830 So really, this is a more useful function than we should have in just the widget controller class. 09:42.830 --> 09:49.430 This is the kind of thing that's worthy of being in a static function library of sorts, right? 09:49.430 --> 09:55.740 So when we get to the point in this course where we make our own function libraries spoiler, we're 09:55.740 --> 10:03.480 going to have things like this in it because this is more versatile than just our overlay widget controller 10:03.480 --> 10:04.200 needs. 10:04.200 --> 10:10.530 So anyway, we have our function and we want to find the row now. 10:10.560 --> 10:11.490 Data table. 10:11.490 --> 10:20.010 The U data table type has a function so we can take data table arrow operator and that function is called 10:20.010 --> 10:21.600 Find Row. 10:21.660 --> 10:28.740 Now find Row itself is a template function that requires a type. 10:28.740 --> 10:37.020 Well, the type that we want to find is going to be T, and this function takes inputs. 10:37.050 --> 10:45.120 It takes a row name, it takes a context string which we don't have to really worry about, and it takes 10:45.120 --> 10:48.240 an optional BOOL that says Warn if row missing. 10:48.240 --> 10:49.860 We'll leave that out. 10:49.860 --> 10:55.200 It has a default value of true so we'll get a warning if we try to find a row that doesn't exist. 10:55.200 --> 11:01.740 So the first input is the only one that really matters and that's going to be the name. 11:01.740 --> 11:03.780 We're finding the row by name. 11:03.780 --> 11:09.990 And remember, the data table row is going to be the same as the tag. 11:09.990 --> 11:17.580 So what we can do is we can take the tag and we can use git tag name because git tag name returns an 11:17.580 --> 11:24.240 F name and that's going to be the name of the tag that's identical with what we named our row. 11:24.240 --> 11:26.310 So this will just happen to work. 11:26.310 --> 11:32.370 Now we need a context string and the context string isn't used for anything. 11:32.370 --> 11:35.100 We can just pass in an empty text string. 11:35.100 --> 11:36.450 That's totally fine. 11:36.630 --> 11:43.820 So find row returns us a look t star because find row is a template function as well. 11:43.830 --> 11:51.720 It uses T and it finds the row and returns the T so we can store this in a local variable of type T 11:51.750 --> 11:52.080 star. 11:52.080 --> 11:55.160 We'll call it row like so. 11:55.160 --> 11:59.480 And once we have the row, we can check because this is a pointer. 11:59.480 --> 12:02.210 We can check to see if it's a valid pointer. 12:02.210 --> 12:02.660 Right? 12:02.660 --> 12:10.100 We can say if row return row row is a T star after all. 12:10.100 --> 12:13.220 And if row is null, we'll return null. 12:14.570 --> 12:19.640 In fact, this is the same thing as return row, same thing. 12:19.640 --> 12:24.860 And in fact, this can just be condensed down to return. 12:25.440 --> 12:26.790 This line, right? 12:26.790 --> 12:30.450 So we really could just do this return. 12:32.850 --> 12:33.870 This line. 12:34.560 --> 12:36.390 So simple function. 12:36.390 --> 12:41.280 You could argue that maybe you don't even need the function and you could just have all this, but this 12:41.280 --> 12:42.540 is a bit of an ugly line. 12:42.540 --> 12:47.760 So I think git data table row by tag is better and we're going to use that. 12:47.910 --> 12:55.470 So here in our lambda, what we can do is we can call get data table row by tag. 12:56.160 --> 13:01.980 And because this is a template function, we have to specify the type, we have to specify T and we 13:01.980 --> 13:07.410 called our struct for our row f UI widget row. 13:07.410 --> 13:09.330 So we're going to specify that. 13:09.330 --> 13:12.120 And we also have to pass in the data table. 13:12.120 --> 13:14.830 And we made that a variable, didn't we? 13:14.850 --> 13:16.440 We made it right here. 13:16.440 --> 13:18.590 It's message widget data table. 13:18.600 --> 13:20.460 We're going to pass in that. 13:22.900 --> 13:24.460 And then we need the tag. 13:24.460 --> 13:26.050 We have the tag right here. 13:26.050 --> 13:26.290 Where? 13:26.290 --> 13:27.400 Inside this for loop. 13:27.400 --> 13:29.770 So we're going to pass in the tag. 13:30.420 --> 13:31.140 Okay. 13:31.140 --> 13:33.750 So that's what we want to do in our lambda. 13:33.780 --> 13:41.760 Now we get the red squiggles and if we hover over them, we see it says invalid use of function, says 13:41.760 --> 13:43.040 the function name. 13:43.050 --> 13:45.280 This is not captured. 13:45.300 --> 13:49.680 Now, this is a very important aspect of lambdas. 13:49.860 --> 13:55.530 When we have a lambda, this is, as we've said, an anonymous function, right? 13:55.530 --> 13:57.780 And it has input parameters. 13:57.780 --> 14:02.430 So we can pass in something like a gameplay tag container as we have here. 14:02.940 --> 14:08.310 And we can do things like call a function on G engine because that's global. 14:08.430 --> 14:16.200 But now we're trying to call a member function that exists on the overlay widget controller, and this 14:16.230 --> 14:20.460 anonymous function doesn't know about the overlay widget controller. 14:20.460 --> 14:26.910 It only knows about what we're passing in and perhaps anything global to the project like this function 14:26.910 --> 14:28.050 it doesn't know about. 14:28.050 --> 14:30.510 Get data table row by tag. 14:30.510 --> 14:33.870 That's where these square brackets come in. 14:33.900 --> 14:37.290 The square brackets are for captures. 14:37.290 --> 14:43.650 If we want to access a member variable from something, then that thing, that class that has the member 14:43.650 --> 14:47.660 variable must be captured within the lambda. 14:47.670 --> 14:55.380 Now we can capture variables, we can capture things by reference, we can capture things by pointer. 14:55.380 --> 15:02.670 And if we want to be able to access get data table row by tag, we have to capture this this object 15:02.670 --> 15:03.650 that we're in. 15:03.660 --> 15:08.520 So a pointer to this is simply the keyword this, right? 15:08.520 --> 15:14.880 So notice as soon as I put this in the square brackets, we're now capturing this, the object that 15:14.880 --> 15:19.620 we're in and that object has get data table row by tag. 15:19.620 --> 15:24.300 It's now defined within the lambda scope within the body of the lambda. 15:24.450 --> 15:31.570 So if you want to call a member function in a lambda, you have to capture that object of the class 15:31.570 --> 15:33.100 that that function belongs to. 15:33.130 --> 15:38.380 So now that we're capturing it, we can call get data table row by tag and that's great. 15:38.410 --> 15:39.700 Now we have the row. 15:39.730 --> 15:43.450 We can even store this in a local variable. 15:43.450 --> 15:50.350 Get data table row by tag, returns a pointer to it so we'll have an UI widget row, we can call it 15:50.350 --> 15:51.130 row. 15:51.130 --> 15:57.370 And now that we have that, we have a pointer to the row and we can do with it what we please. 15:57.370 --> 15:58.750 Now, what we please. 15:58.750 --> 16:03.670 What we want to do is we want to send this row up to the widget. 16:03.700 --> 16:06.490 We want to broadcast it up to the widget. 16:06.520 --> 16:14.200 In other words, we want to delegate that can send through an UI widget row and we're going to do that 16:14.200 --> 16:14.980 next. 16:15.070 --> 16:17.560 So great job and I'll see you soon.