1 00:00:04,200 --> 00:00:05,670 ‫Hey, welcome back. 2 00:00:05,700 --> 00:00:12,630 ‫In the last video, we learned a few new property specifiers that allow us to expose our C++ variables 3 00:00:12,630 --> 00:00:16,110 ‫in certain ways to the details panel in the blueprints. 4 00:00:16,110 --> 00:00:22,260 ‫In this video, we're going to learn some more specifiers that allow us to have more control over access 5 00:00:22,260 --> 00:00:23,430 ‫to those variables. 6 00:00:23,430 --> 00:00:29,400 ‫In the details panel, we're also going to talk about how we can allow, read or write access in the 7 00:00:29,400 --> 00:00:33,330 ‫actual event graph for a particular C++ variable. 8 00:00:33,330 --> 00:00:34,860 ‫So let's dive right in. 9 00:00:35,310 --> 00:00:35,820 ‫Okay. 10 00:00:35,820 --> 00:00:41,640 ‫So I'm back here in VS code and here are the variables we created in the last video. 11 00:00:41,670 --> 00:00:44,130 ‫Now here is my speed variable. 12 00:00:44,130 --> 00:00:45,900 ‫This was for the challenge. 13 00:00:45,900 --> 00:00:51,510 ‫You probably created a different variable, which is totally fine, so keep that variable there. 14 00:00:51,510 --> 00:00:53,880 ‫We're going to do some more things with it in this video. 15 00:00:53,880 --> 00:00:59,760 ‫Now we've learned that we can make a variable visible anywhere, and when we say anywhere, we mean 16 00:00:59,760 --> 00:01:04,110 ‫on the details panel, either on an instance or on the default blueprint. 17 00:01:04,140 --> 00:01:11,550 ‫We saw that we can also make it edit anywhere, and when we use visible instance only, it's only visible 18 00:01:11,580 --> 00:01:12,600 ‫on an instance. 19 00:01:12,600 --> 00:01:17,430 ‫You can't even see it on the default blueprint and in any case, you can't edit it because it's grayed 20 00:01:17,430 --> 00:01:17,820 ‫out. 21 00:01:17,820 --> 00:01:21,330 ‫So this allows us to make our variable visible only on the instance. 22 00:01:21,330 --> 00:01:25,080 ‫But what if we'd like it to be visible only on the default blueprint? 23 00:01:25,080 --> 00:01:27,360 ‫Well, there's a specifiers for that too. 24 00:01:27,390 --> 00:01:34,560 ‫Let's make another in 32 and let's call this visible defaults only int. 25 00:01:35,210 --> 00:01:37,520 ‫And we can initialize this to a value. 26 00:01:37,520 --> 00:01:41,930 ‫I'm going to give it five and we'll give this a U property as well. 27 00:01:41,930 --> 00:01:45,640 ‫And the specify are for making this visible only on the defaults. 28 00:01:45,650 --> 00:01:47,780 ‫You can probably guess what it is. 29 00:01:47,780 --> 00:01:50,810 ‫It's visible defaults only. 30 00:01:50,810 --> 00:01:56,960 ‫So I'm going to compile this and back here in the editor, I'm going to open up BP Pond Tank again. 31 00:01:56,960 --> 00:02:02,210 ‫And with BP Pond Tank self-selected, all of our variables are up here at the top, so I'm not going 32 00:02:02,210 --> 00:02:03,170 ‫to search for it. 33 00:02:03,170 --> 00:02:09,620 ‫But here's our visible defaults only int and it's got the value five and of course it's grayed out now 34 00:02:09,620 --> 00:02:12,500 ‫as the name suggests, it's visible only on the default. 35 00:02:12,500 --> 00:02:19,370 ‫So if I go in the world and select one of the instances of BP pond tank here, there is no visible defaults 36 00:02:19,370 --> 00:02:23,540 ‫only int it's not visible on the instance, only on the default. 37 00:02:23,540 --> 00:02:25,100 ‫So that makes sense right now. 38 00:02:25,100 --> 00:02:30,860 ‫Let's go back into VS code and we have a few more specifiers to learn about. 39 00:02:30,890 --> 00:02:36,680 ‫Now we've seen that we can edit anywhere and that with our visible specifiers we can choose instance 40 00:02:36,680 --> 00:02:38,360 ‫only or default only. 41 00:02:38,360 --> 00:02:45,710 ‫So as you've probably guessed, we can edit on only the instance or only the defaults if we choose. 42 00:02:45,710 --> 00:02:48,140 ‫So let's make a couple more in 30 twos. 43 00:02:48,140 --> 00:02:55,310 ‫I'm going to make one called edit defaults only int and initialize that to a value say nine and then 44 00:02:55,310 --> 00:03:00,020 ‫another int 32 called edit instance only int. 45 00:03:00,020 --> 00:03:02,600 ‫And I'll give this a value of 14. 46 00:03:02,600 --> 00:03:09,740 ‫So we want edit defaults only int to be editable only on the defaults and edit instance only and to 47 00:03:09,740 --> 00:03:11,900 ‫be editable only on the instance. 48 00:03:11,900 --> 00:03:17,870 ‫Now the names of these specifiers are pretty consistent, so I'd like you to just guess what the specifiers 49 00:03:17,870 --> 00:03:20,360 ‫would be for these two access levels. 50 00:03:20,390 --> 00:03:23,150 ‫Go ahead and just do a quick little mini challenge. 51 00:03:23,150 --> 00:03:26,330 ‫Pause the video and fill these in, see if you're right. 52 00:03:29,030 --> 00:03:32,570 ‫Okay so these are going to be you properties and edit defaults. 53 00:03:32,600 --> 00:03:35,600 ‫Only end is going to get you probably guessed it. 54 00:03:35,600 --> 00:03:44,060 ‫Edit defaults only and for edit instance only int I'll give this a u property macro and this will be 55 00:03:44,060 --> 00:03:46,400 ‫edit instance only. 56 00:03:46,400 --> 00:03:47,810 ‫So it's pretty intuitive. 57 00:03:47,840 --> 00:03:54,530 ‫Let's go ahead and compile these and back here in the editor with BP -- tank open here's our edit 58 00:03:54,530 --> 00:04:01,100 ‫defaults only int we don't see edit instance only and we didn't expect to it's set to nine here we can 59 00:04:01,100 --> 00:04:08,090 ‫change it and if we go into the world with one of our instances selected we can see edit instance only 60 00:04:08,090 --> 00:04:10,790 ‫int and of course that's editable as well. 61 00:04:10,970 --> 00:04:14,840 ‫So we've now added three new specifiers to our graph here. 62 00:04:14,840 --> 00:04:21,020 ‫We have visible defaults only, which is in only the default column and in the read only row. 63 00:04:21,050 --> 00:04:26,450 ‫And then we have edit defaults only and edit instance only in their respective rows. 64 00:04:26,600 --> 00:04:31,880 ‫So we're filling up this graph pretty quickly, but you'll notice that there are a couple of spaces 65 00:04:31,880 --> 00:04:35,840 ‫empty over there to the right and the event graph column. 66 00:04:35,840 --> 00:04:38,300 ‫So let's talk about these for a minute now. 67 00:04:38,300 --> 00:04:45,230 ‫I'm here in BP Pond Tank, and we have all of these variables that we've exposed to the details, panels, 68 00:04:45,410 --> 00:04:47,030 ‫depending on their specifiers. 69 00:04:47,060 --> 00:04:49,370 ‫You can see them here or on an instance. 70 00:04:49,370 --> 00:04:52,010 ‫But what if I right click here in the event graph? 71 00:04:52,040 --> 00:04:57,440 ‫The event graph is another place where we can access variables and potentially change them. 72 00:04:57,440 --> 00:05:02,150 ‫So if I type edit anywhere, I do not see the edit anywhere. 73 00:05:02,150 --> 00:05:05,090 ‫INT it's not exposed to the event graph. 74 00:05:05,090 --> 00:05:06,860 ‫We don't have access to that. 75 00:05:06,860 --> 00:05:13,460 ‫There is another specifiers that allows us to expose things here in the event graph and that can work 76 00:05:13,460 --> 00:05:18,800 ‫in conjunction with the specifiers that control the details panel accessibility. 77 00:05:18,800 --> 00:05:23,150 ‫And I'd like to expose one of these variables to the event graph. 78 00:05:23,150 --> 00:05:26,870 ‫Now, I could choose any one of these, but I'm going to choose this visible anywhere. 79 00:05:26,870 --> 00:05:27,830 ‫INT Now the U. 80 00:05:27,830 --> 00:05:32,630 ‫Property macro can take multiple inputs, so we have visible anywhere. 81 00:05:32,630 --> 00:05:34,010 ‫We can still have that. 82 00:05:34,010 --> 00:05:39,920 ‫I'm going to place a comma and I'd like to add another specified to that will give this visible anywhere 83 00:05:39,920 --> 00:05:42,680 ‫end exposure to the event graph. 84 00:05:42,680 --> 00:05:48,650 ‫So what I'm going to use is blueprint read, write, blueprint read. 85 00:05:48,650 --> 00:05:51,230 ‫Write has to do with the event graph. 86 00:05:51,350 --> 00:05:54,500 ‫It has nothing to do with control over the details panel. 87 00:05:54,500 --> 00:05:57,140 ‫That's what this visible anywhere is for. 88 00:05:57,140 --> 00:06:02,570 ‫So Blueprint Rewrite does, as the name suggests, read access and write access. 89 00:06:02,570 --> 00:06:04,240 ‫So let's see how that looks. 90 00:06:04,250 --> 00:06:11,030 ‫Let's compile this and I'm back here in the editor in the event graph if I right click and type visible 91 00:06:11,030 --> 00:06:11,960 ‫anywhere. 92 00:06:12,660 --> 00:06:18,630 ‫We'll see two different options get visible anywhere int and set visible anywhere. 93 00:06:18,630 --> 00:06:21,330 ‫INT If you select, get visible anywhere. 94 00:06:21,330 --> 00:06:27,690 ‫INT We get a node and this is just like any other blueprint node, it represents that C++ variable and 95 00:06:27,690 --> 00:06:32,430 ‫if we drag off of this, we can access that value to do something with it. 96 00:06:32,430 --> 00:06:38,400 ‫Now I'm going to scroll out and you'll see that we have these grayed out nodes actor begin, overlap 97 00:06:38,400 --> 00:06:43,500 ‫and event tick and Begin Play is called at the beginning of the game as you know. 98 00:06:43,500 --> 00:06:45,120 ‫So we can do something here. 99 00:06:45,120 --> 00:06:51,750 ‫I'd like to use a print string node and if I drag off and type print string, then here it is. 100 00:06:51,750 --> 00:06:57,750 ‫It's a blueprint function node and it takes a input called in string. 101 00:06:57,750 --> 00:07:02,250 ‫Now if I hover over it, it says in string and then string right below that. 102 00:07:02,250 --> 00:07:05,940 ‫That's the type that this node accepts as an input parameter. 103 00:07:05,940 --> 00:07:10,260 ‫And we know that our visible anywhere int is an int 32, not a string. 104 00:07:10,260 --> 00:07:17,400 ‫But if you click from the output of this note and drag and stick it right here in the input before you 105 00:07:17,400 --> 00:07:23,370 ‫release the left mouse button, you see a pop up that says convert integer to string and if you release 106 00:07:23,370 --> 00:07:29,850 ‫then you get this handy conversion node that converts from an integer to the string type, which is 107 00:07:29,850 --> 00:07:34,650 ‫very handy for us because we don't have to figure out how to convert an integer to a string. 108 00:07:34,650 --> 00:07:36,480 ‫It's just automatic for us. 109 00:07:36,510 --> 00:07:42,540 ‫Now, if I hit play, we'll see the value 12 printed three times and it only lasts for a few seconds. 110 00:07:42,540 --> 00:07:44,430 ‫That's the behavior of print string. 111 00:07:44,430 --> 00:07:50,550 ‫Now, the reason we see it three times is because I have three different instances of BP pond tank here 112 00:07:50,550 --> 00:07:51,330 ‫in the world. 113 00:07:51,330 --> 00:07:54,900 ‫Depending on how many you've dragged into the world, you'll see that many. 114 00:07:54,900 --> 00:08:00,210 ‫Because for each of these individual instances, begin play is getting called at the beginning of the 115 00:08:00,210 --> 00:08:00,630 ‫game. 116 00:08:00,630 --> 00:08:06,180 ‫So just to avoid confusion, I'm going to just delete my other two and just leave a single instance 117 00:08:06,180 --> 00:08:08,220 ‫of Beep Pond Tank here in the world. 118 00:08:08,220 --> 00:08:15,270 ‫So I have only one and if I go and hit play again then I see 12 printed to the screen only once. 119 00:08:15,270 --> 00:08:21,840 ‫So that is read access to visible anywhere int but we saw that we also have write access. 120 00:08:21,840 --> 00:08:24,960 ‫That means we can set its value from here in the event graph. 121 00:08:24,960 --> 00:08:32,220 ‫So if I right click and type visible anywhere int again then I can select set visible anywhere int and 122 00:08:32,220 --> 00:08:38,850 ‫I have a setter node which takes an input we can pass in the value from some other node or we can take 123 00:08:38,850 --> 00:08:42,900 ‫this little text box and hard code of value, say 66. 124 00:08:42,900 --> 00:08:48,660 ‫And now as soon as the flow of execution from begin play reaches this node, then the setter node is 125 00:08:48,660 --> 00:08:54,480 ‫going to write to visible anywhere and it's going to set its value to 66. 126 00:08:54,480 --> 00:08:56,610 ‫And of course we can print this out again. 127 00:08:56,610 --> 00:08:58,590 ‫So I'm going to use print string. 128 00:09:00,070 --> 00:09:05,700 ‫And for the value passed into print string, I'd like the value of visible anywhere int. 129 00:09:05,710 --> 00:09:07,720 ‫Now I can do this one of two ways. 130 00:09:07,720 --> 00:09:13,990 ‫The setter has a return node, so after it set the value, then it returns that value and we can use 131 00:09:13,990 --> 00:09:16,990 ‫it so we can plug it straight in to print string. 132 00:09:16,990 --> 00:09:23,770 ‫The other way is to simply right click and get visible anywhere int use that get node and we can hook 133 00:09:23,770 --> 00:09:29,470 ‫up the value from this node right into print string that would do the exact same thing. 134 00:09:29,470 --> 00:09:30,700 ‫So I don't need that. 135 00:09:30,700 --> 00:09:31,960 ‫I'm going to delete that node. 136 00:09:31,960 --> 00:09:38,680 ‫And now what I'm expecting to see when I play the game is to first print out the value of visible anywhere 137 00:09:38,680 --> 00:09:46,480 ‫int, which starts off at 12 and then after setting its value to 66, I should see the value 66 print 138 00:09:46,480 --> 00:09:47,320 ‫it out to the screen. 139 00:09:47,320 --> 00:09:50,560 ‫So let's hit play and we see 12 and 66. 140 00:09:50,560 --> 00:09:52,540 ‫Now they look like they're in reverse order. 141 00:09:52,540 --> 00:09:56,170 ‫That's because print string adds newer messages on top. 142 00:09:56,170 --> 00:09:58,270 ‫So that is normal behavior. 143 00:09:58,270 --> 00:09:59,110 ‫Okay, great. 144 00:09:59,110 --> 00:10:02,800 ‫So we've seen that we can make a variable blueprint read right now. 145 00:10:02,800 --> 00:10:07,210 ‫We can also control whether or not we can set this from the event graph. 146 00:10:07,210 --> 00:10:13,450 ‫So let's expose another variable so that we can get it from blueprints but not set it here's edit anywhere. 147 00:10:13,450 --> 00:10:20,080 ‫INT I'm going to add a comma and add a specified to to this now in order to access it in the event graph 148 00:10:20,080 --> 00:10:22,930 ‫but not be able to set it or write to it. 149 00:10:22,930 --> 00:10:30,520 ‫The specify hour is blueprint read only so edit anywhere int is now blueprint read only. 150 00:10:30,520 --> 00:10:37,570 ‫It's still editable in the details panel, both in the default and on instances, but in the event graph 151 00:10:37,570 --> 00:10:38,470 ‫it's read only. 152 00:10:38,470 --> 00:10:44,080 ‫So let's go ahead and compile this and back here in the editor, I'm going to right click in the event 153 00:10:44,080 --> 00:10:47,080 ‫graph and type edit anywhere and check it out. 154 00:10:47,080 --> 00:10:53,050 ‫We have get edit anywhere end but we do not have a set edit anywhere int because it's blueprint read 155 00:10:53,050 --> 00:10:55,240 ‫only, we cannot write to it. 156 00:10:55,240 --> 00:10:56,650 ‫So I'm going to select it. 157 00:10:56,650 --> 00:10:57,910 ‫Here's edit anywhere. 158 00:10:57,910 --> 00:11:03,250 ‫INT And if I wanted to I could use a print string node to see its value. 159 00:11:03,280 --> 00:11:04,360 ‫No need to do that. 160 00:11:04,360 --> 00:11:05,680 ‫We already know how to do that. 161 00:11:05,680 --> 00:11:09,760 ‫I'm just demonstrating that we cannot write to this variable. 162 00:11:09,790 --> 00:11:13,630 ‫Okay, so I'm going to go ahead and highlight these nodes and delete them. 163 00:11:13,630 --> 00:11:15,880 ‫So our graph is now filled out. 164 00:11:15,880 --> 00:11:21,700 ‫We've learned that we can make our variables visible only on the defaults and we can make them editable 165 00:11:21,700 --> 00:11:24,550 ‫only on the defaults or only on the instance. 166 00:11:24,550 --> 00:11:27,820 ‫So we really have full control from the C++ side. 167 00:11:27,850 --> 00:11:34,240 ‫Now we also saw that we can expose these variables to the event graph and make them read only or read 168 00:11:34,240 --> 00:11:38,650 ‫right using these blueprint read only, blueprint read write specifiers. 169 00:11:38,650 --> 00:11:40,180 ‫So now you have a challenge. 170 00:11:40,180 --> 00:11:43,330 ‫In the last lecture we created a variable. 171 00:11:43,330 --> 00:11:45,310 ‫I made a float and called it speed. 172 00:11:45,340 --> 00:11:46,960 ‫Now you're going to take that variable. 173 00:11:46,960 --> 00:11:52,180 ‫You create it in the last section and control its access in the event graph. 174 00:11:52,180 --> 00:11:57,700 ‫So expose it to the event graph using one of the new specifiers you've learned, and then you're going 175 00:11:57,700 --> 00:12:00,520 ‫to test out the read write access for this. 176 00:12:00,520 --> 00:12:06,040 ‫Use a print string node so that you can see its value and if you change it, prove to yourself that 177 00:12:06,040 --> 00:12:07,000 ‫you've changed it. 178 00:12:07,000 --> 00:12:12,520 ‫So if you make your variable blueprint read right, try changing it with a set node and then using a 179 00:12:12,520 --> 00:12:15,880 ‫print string node to see its value using event begin play. 180 00:12:15,880 --> 00:12:21,640 ‫If you made it blueprint read only then you can simply get the value and print its value using print 181 00:12:21,640 --> 00:12:22,120 ‫string. 182 00:12:22,120 --> 00:12:29,080 ‫So add the correct specify to your custom variable and use print string to test out access in the event 183 00:12:29,080 --> 00:12:29,590 ‫graph. 184 00:12:29,590 --> 00:12:31,780 ‫Pause the video and give this a try. 185 00:12:34,570 --> 00:12:34,990 ‫Okay. 186 00:12:34,990 --> 00:12:40,330 ‫So I'm going to scroll down to my speed variable here and my speed variable is edit anywhere and I'd 187 00:12:40,330 --> 00:12:41,620 ‫like it to be blueprint read. 188 00:12:41,620 --> 00:12:44,530 ‫Right, so I can change it from within the event graph. 189 00:12:44,530 --> 00:12:49,110 ‫So I'm going to add blueprint, read, write and simply compile. 190 00:12:49,120 --> 00:12:55,990 ‫So back in BP pond tank, if I type speed now I see the getter and setter for this. 191 00:12:56,110 --> 00:12:58,180 ‫So I'm going to use set speed. 192 00:12:58,330 --> 00:13:00,940 ‫I'm going to set its value from Begin Play. 193 00:13:00,940 --> 00:13:01,930 ‫So let's hook this up. 194 00:13:01,930 --> 00:13:09,640 ‫And for the value, I'm going to enter 900 and from the set note if I drag off I can type print string. 195 00:13:09,640 --> 00:13:13,780 ‫Now I'm going to click and drag off of the output node, hook it up to string. 196 00:13:13,780 --> 00:13:18,370 ‫So if I hit play, there's 900, notice it says 900.0. 197 00:13:18,370 --> 00:13:19,960 ‫That's because this is a float. 198 00:13:19,960 --> 00:13:24,190 ‫And so it's giving me the courtesy of showing that first decimal point. 199 00:13:24,190 --> 00:13:26,680 ‫So that's kind of a nice built in feature here. 200 00:13:26,680 --> 00:13:31,630 ‫It's showing me one digit to the right of the decimal point for my speed variable. 201 00:13:31,630 --> 00:13:36,550 ‫So in summary, we learned some more specifiers for the new property macro. 202 00:13:36,580 --> 00:13:41,650 ‫We learned visible defaults only, edit defaults only and edit instance only. 203 00:13:41,650 --> 00:13:47,110 ‫And we also learned how we can control read write access in the event graph with Blueprint, read, 204 00:13:47,110 --> 00:13:48,550 ‫write and Blueprint Read. 205 00:13:48,550 --> 00:13:56,350 ‫Only the C++ programmer has a great deal of control over what gets exposed and what can be changed in 206 00:13:56,350 --> 00:14:01,060 ‫the blueprint and where we'll be using these throughout this section of the course. 207 00:14:01,210 --> 00:14:05,620 ‫And you'll continue to use them throughout your career as an unreal engine developer. 208 00:14:06,130 --> 00:14:07,510 ‫I'll see you in the next lecture.