1 00:00:04,020 --> 00:00:04,980 ‫Hello and welcome. 2 00:00:04,980 --> 00:00:11,100 ‫In this lecture, we're going to be making it so that when you use up all of your projectiles, your 3 00:00:11,100 --> 00:00:14,010 ‫game will automatically restart the current level. 4 00:00:14,010 --> 00:00:18,810 ‫After a pause of 5 seconds, let's dive in and see how this is done. 5 00:00:19,080 --> 00:00:24,660 ‫So one element of this game that's not particularly fun right now is that when you run out of ammo, 6 00:00:24,660 --> 00:00:25,650 ‫it's a dead end. 7 00:00:25,650 --> 00:00:26,910 ‫You can't try again. 8 00:00:26,910 --> 00:00:27,930 ‫You can't do anything else. 9 00:00:27,930 --> 00:00:29,820 ‫You can't move on to another level. 10 00:00:30,150 --> 00:00:38,160 ‫Now, the way you can fix this is by allowing us to reload the current level. 11 00:00:38,880 --> 00:00:42,750 ‫The way you can do that is using a special node in blueprint. 12 00:00:42,750 --> 00:00:47,430 ‫So if you right click in the event graph, you open up your level blueprint and right click in the event 13 00:00:47,430 --> 00:00:47,850 ‫graph. 14 00:00:48,180 --> 00:00:50,580 ‫We can search for open level. 15 00:00:50,580 --> 00:00:51,720 ‫And there's two options here. 16 00:00:51,720 --> 00:00:55,650 ‫There's an open level by name and an open level by object reference. 17 00:00:55,800 --> 00:00:59,520 ‫We can use the open level by name. 18 00:00:59,520 --> 00:01:06,510 ‫So here you got a node that obviously has side effects because it's going to reload the level and it 19 00:01:06,510 --> 00:01:09,150 ‫has an input, which is the level name here. 20 00:01:09,600 --> 00:01:12,000 ‫Now how do we get hold of the current level name? 21 00:01:12,000 --> 00:01:19,050 ‫We could just type it in, but what if we accidentally renamed this level at some point in the future? 22 00:01:19,350 --> 00:01:28,710 ‫Well, what we can do is also right click and do a get current level name, which gets us another node 23 00:01:28,710 --> 00:01:30,930 ‫that returns the current level name. 24 00:01:30,930 --> 00:01:33,990 ‫Interestingly enough, this one isn't a pure function. 25 00:01:33,990 --> 00:01:35,070 ‫I have no idea why. 26 00:01:35,130 --> 00:01:36,840 ‫Because it looks like it should be. 27 00:01:36,930 --> 00:01:42,150 ‫And what we can do is even though these two types are different, one of them returns a string and the 28 00:01:42,150 --> 00:01:44,400 ‫other one requires something of type name. 29 00:01:44,400 --> 00:01:51,120 ‫It's actually possible to very easily convert between strings and names so we can drag from the return 30 00:01:51,120 --> 00:01:56,430 ‫value to the input value, and a conversion node will automatically be created for us. 31 00:01:56,430 --> 00:02:01,350 ‫We also need to hook up the execution pin between these two, so we're going to get the current level 32 00:02:01,350 --> 00:02:04,380 ‫name convert and then open the level. 33 00:02:04,800 --> 00:02:06,870 ‫Now when is it that we want to do this? 34 00:02:06,870 --> 00:02:12,900 ‫Currently everything is happening either on a key event or begin play, but there is another option. 35 00:02:12,900 --> 00:02:20,640 ‫What we can do is we can have a special node in the root event graph, so not within functions but within 36 00:02:20,640 --> 00:02:23,010 ‫the root event graph called a delay node. 37 00:02:23,010 --> 00:02:29,220 ‫So what we're going to do is after the out of ammo is pressed, we're going to pull off of the execution 38 00:02:29,220 --> 00:02:31,560 ‫pin here and search for delay. 39 00:02:32,220 --> 00:02:37,080 ‫And then you can see it brings in a special kind of node with a clock on it. 40 00:02:37,080 --> 00:02:45,480 ‫And this means that the output happens not instantly after the function has finished, but it happens 41 00:02:45,480 --> 00:02:47,040 ‫after a certain amount of time. 42 00:02:47,040 --> 00:02:53,490 ‫So you can see we can input the duration here, and that duration could be 5 seconds, for example. 43 00:02:53,490 --> 00:03:04,020 ‫So in my print string, I'm going to update it to say out of ammo restarting in 5 seconds and then dot, 44 00:03:04,020 --> 00:03:04,710 ‫dot, dot. 45 00:03:05,100 --> 00:03:15,300 ‫And then we can plug in the code that restarts the level into the output, the completed node of the 46 00:03:15,300 --> 00:03:16,650 ‫delay node. 47 00:03:16,740 --> 00:03:24,390 ‫So if we go ahead and play now, what we're going to see is that I can run out of ammo, finish all 48 00:03:24,390 --> 00:03:31,530 ‫of my ammo, I run out and it says I'm restarting in 5 seconds and after 5 seconds has elapsed, boom, 49 00:03:31,530 --> 00:03:33,540 ‫the level has just restarted. 50 00:03:33,540 --> 00:03:40,950 ‫So small challenge for this lecture is to extract a function from those nodes that we've just created, 51 00:03:40,950 --> 00:03:43,830 ‫the get current level, name and open level. 52 00:03:43,830 --> 00:03:48,810 ‫And my challenge to you is to just think of a good name for this function. 53 00:03:48,810 --> 00:03:50,430 ‫Pause the video and have a go. 54 00:03:53,740 --> 00:03:54,050 ‫Okay. 55 00:03:54,060 --> 00:03:54,660 ‫Welcome back. 56 00:03:54,660 --> 00:03:59,370 ‫Well, I'm going to call it restart level because that's what I think it's doing. 57 00:03:59,370 --> 00:04:07,950 ‫So I'm going to right click collapse to function and call it restart level and it's fine with the current 58 00:04:07,950 --> 00:04:08,460 ‫inputs. 59 00:04:08,460 --> 00:04:12,690 ‫It doesn't need to be pure because it has the side effect of restarting the level. 60 00:04:12,690 --> 00:04:14,970 ‫So we wouldn't want it to be pure anyway. 61 00:04:14,970 --> 00:04:15,690 ‫So that's it. 62 00:04:15,690 --> 00:04:22,170 ‫I'm just going to reorganize my nodes ever so slightly and delete my test node and delete my test function 63 00:04:22,170 --> 00:04:25,170 ‫by right clicking on it in the my blueprints and hitting delete. 64 00:04:25,470 --> 00:04:33,240 ‫And we've got ourselves a condensed little blueprint graph that actually describes exactly what our 65 00:04:33,240 --> 00:04:36,420 ‫game can do just at a very high level. 66 00:04:36,420 --> 00:04:37,830 ‫So I'm pleased with the results of that. 67 00:04:37,830 --> 00:04:41,640 ‫Feels like we've got a good game loop and I'll see you in the next lecture.