WEBVTT 00:06.840 --> 00:07.930 Welcome back. 00:07.950 --> 00:11.280 Now we're calculating some spawn locations. 00:11.280 --> 00:17.670 But one important feature that I'd like is to be able to spawn my minions asynchronously. 00:17.700 --> 00:20.500 Not necessarily all at the same time. 00:20.520 --> 00:26.250 I'd like to spawn them all one after the other, perhaps, and not necessarily in order either. 00:26.250 --> 00:32.910 So in this video we're going to work on an algorithm for spawning them asynchronously. 00:32.910 --> 00:38.520 So to do that, first of all, after we get our spawn locations in our summon ability, I'm going to 00:38.520 --> 00:43.770 promote that array to a variable and I'm going to call this spawn locations. 00:43.800 --> 00:53.070 Now, after the spawn locations array is stored, I'd like to draw a debug sphere for each of them, 00:53.070 --> 00:54.960 but I don't want to use a for loop. 00:54.960 --> 00:56.850 I don't want to use a while loop. 00:56.850 --> 01:02.490 Those are all going to loop over every single element in this array all at once. 01:02.520 --> 01:06.150 Atomically if you will, all in the same frame. 01:06.150 --> 01:09.430 I want to do this over the space of multiple frames. 01:09.430 --> 01:14.380 So what I'm going to do is keep count of which of these spawn locations. 01:14.380 --> 01:18.420 I'm at a spawn location index, if you will. 01:18.430 --> 01:20.320 So I'm going to create a new variable. 01:20.320 --> 01:25.510 It's going to be an integer, and I'm going to call this spawn location index. 01:25.660 --> 01:31.780 It'll start off at zero, but I'm going to have a loop, not a while loop, not a for loop, but just 01:31.780 --> 01:36.370 a blueprint loop right here where I'm going to check first. 01:36.370 --> 01:43.420 If my spawn location index is less than the number of elements in that array, so I'm going to use a 01:43.420 --> 01:47.650 less than node and get my spawn locations array. 01:48.390 --> 01:49.590 Get its length. 01:51.270 --> 01:53.760 And take that length and pass it in. 01:55.310 --> 01:58.640 And use this as a condition for my branch. 01:59.920 --> 02:06.890 So as long as spawn location index is less than spawn locations length, then we'll continue. 02:06.910 --> 02:11.190 And for now, I'm just going to draw a debug sphere. 02:11.200 --> 02:13.300 So draw debug sphere here. 02:15.740 --> 02:18.160 And this one will be a little bit bigger. 02:18.170 --> 02:26.900 We'll make it have a radius of 25 and its center is going to be at Spawn locations. 02:26.900 --> 02:35.150 So I'm going to get Spawn locations and I'm going to get a copy at Spawn Location Index, and that's 02:35.150 --> 02:37.010 where I'm going to draw the debug sphere. 02:37.010 --> 02:45.590 So we're choosing that one and I'm going to make this a red, probably magenta color with a duration 02:45.590 --> 02:48.050 of three like so. 02:48.050 --> 02:55.250 Now after I've chosen and drawn a debug sphere, I'm going to take spawn location index and increment 02:55.250 --> 02:56.000 it by one. 02:56.000 --> 02:59.270 So I'm going to use a plus plus operator. 02:59.950 --> 03:01.690 We're going to add one to it. 03:01.690 --> 03:04.870 And after that, I'd like to repeat the process. 03:04.870 --> 03:09.460 I'd like this to loop back around all the way back to the branch again. 03:09.490 --> 03:14.980 Now, we can't tell that this is looping around, so I'm going to drag this node up, add a reroute 03:15.010 --> 03:19.900 node and drag it back down like this so we can see that it's looping. 03:19.900 --> 03:24.370 I'm going to add two reroute nodes like so and we can see that it's a loop. 03:24.460 --> 03:31.120 Now I don't want this to happen immediately, otherwise this is just a glorified while loop. 03:31.120 --> 03:34.390 I'm going to add a delay right here at the end. 03:34.420 --> 03:38.110 So a delay node, it can be 0.2 seconds, That's fine. 03:38.110 --> 03:42.100 And every 0.2 seconds we'll go back around. 03:42.100 --> 03:48.550 We'll check that spawn location index, makes sure we're not out of bounds, and then we'll pick the 03:48.550 --> 03:55.150 spawn location and draw the debug sphere increment spawn location index and start again. 03:55.360 --> 04:00.710 So let's go ahead and try this out and see what happens. 04:00.710 --> 04:01.520 And there we go. 04:01.520 --> 04:03.890 We see those magenta spheres. 04:03.920 --> 04:06.230 Now the thing is they're going in order. 04:06.230 --> 04:08.090 So it's not very random. 04:08.090 --> 04:11.570 It's going from right to left from our perspective. 04:11.600 --> 04:17.150 So if we really wanted this to look a little bit more random, we could shuffle the array. 04:17.180 --> 04:20.210 Now there happens to be a function for doing that. 04:20.240 --> 04:26.000 We can right click type shuffle and we have utilities array shuffle. 04:26.030 --> 04:29.660 This takes in an array and it's going to do what it says. 04:29.660 --> 04:31.280 It's going to shuffle that array. 04:31.370 --> 04:36.650 So now if we press play, we can see that it's no longer going in order. 04:36.650 --> 04:42.590 We're seeing those magenta spheres and it's a little bit distracting with all the other debug shapes. 04:42.590 --> 04:48.590 So at this point I'm going to go ahead and just remove the other debug shapes from our algorithm. 04:48.710 --> 04:50.570 We don't need those anymore. 04:50.600 --> 04:53.810 They're still in the commit for last lecture. 04:53.810 --> 05:00.140 So you can always go back to the GitHub and see that commit, but I don't think we need them anymore. 05:00.170 --> 05:02.990 So I'm going to go ahead and launch once again. 05:03.410 --> 05:08.180 And I'm noticing before I go back there's a couple of dead includes here. 05:08.180 --> 05:13.640 Sometimes writer auto includes things and sometimes I remove things that don't need anymore. 05:13.640 --> 05:15.260 So I'm just removing those. 05:15.260 --> 05:22.160 Next time we compile that will be there, I'm going to go ahead and open that summon ability and we're 05:22.160 --> 05:23.600 going to play test. 05:24.450 --> 05:27.270 And there we see our spawn location. 05:27.270 --> 05:36.150 So as you can see, it's a pretty nice semi-random algorithm that gives us some good looking spawn locations. 05:36.150 --> 05:39.840 We have a nice spread there, so that's looking good. 05:40.350 --> 05:43.830 Now, the thing is that we could be on a hill. 05:43.830 --> 05:47.100 We're not always necessarily going to be on flat ground. 05:47.130 --> 05:50.190 There could be stairs, there could be a ramp. 05:50.190 --> 05:58.920 And so it might be wise if we just make sure that our spawn locations are always on the ground. 05:59.070 --> 06:08.400 And for that reason we can do a line trace straight down from above on those locations and then we'll 06:08.400 --> 06:16.110 get those spawn locations and they won't necessarily be under the ground or too far above the ground. 06:16.110 --> 06:22.170 So before we wrap up, let's go ahead and just make sure that those spawn locations are exactly on the 06:22.170 --> 06:22.710 ground. 06:22.740 --> 06:27.030 So I'm going to close and come back to get Spawn locations. 06:27.030 --> 06:34.740 And each time we get a chosen location, I'm going to do a line trace from above and we're going to 06:34.740 --> 06:37.830 store the hit result of that line trace. 06:38.160 --> 06:40.480 So I'm going to call get World. 06:42.150 --> 06:45.540 Line trace single by channel. 06:45.570 --> 06:47.460 We're going to need a hit result. 06:47.460 --> 06:50.190 So f hit results hit. 06:50.310 --> 06:51.840 We'll pass that in. 06:52.590 --> 06:58.470 We're going to need a start location, and that's going to be our chosen spawn location. 06:58.470 --> 07:00.000 But we're going to add to it. 07:00.000 --> 07:02.160 We're going to add a vector pointing straight up. 07:02.160 --> 07:11.430 So F vector it's going to be zero point f zero dot f, and we'll go a nice, let's say, 500 units. 07:11.430 --> 07:12.900 That might be too much. 07:12.900 --> 07:21.530 Let's do 400 units in the air and the end is going to be the same location minus that much. 07:21.540 --> 07:24.180 So this will be well into the ground. 07:24.180 --> 07:31.410 We'll change this to a minus here, and that way we'll trace to just below that spawn location by 400 07:31.410 --> 07:32.280 units. 07:32.400 --> 07:39.300 So we have our hit, we have our start location, we have our end location, and we need a collision 07:39.300 --> 07:39.780 channel. 07:39.780 --> 07:44.830 We're going to chase against SEC, underscore visibility. 07:45.670 --> 07:47.470 So there's our line trace. 07:47.500 --> 07:57.640 Now what we'll do is if we get a blocking hit, so if hit dot be blocking hit, then we're going to 07:57.640 --> 08:02.770 change our spawn location to the hit result impact point. 08:02.770 --> 08:09.280 So I'm going to remove const from chosen spawn location and if we get a blocking hit, I'm going to 08:09.280 --> 08:16.210 overwrite chosen spawn location with hit dot impact point like so. 08:16.210 --> 08:20.530 And now our spawn locations should all be on the ground. 08:20.560 --> 08:22.180 Let's test that out. 08:22.990 --> 08:23.770 Here we go. 08:23.770 --> 08:24.880 Let's hit play. 08:25.810 --> 08:26.750 And there they are. 08:26.770 --> 08:28.420 They're all on the ground. 08:28.540 --> 08:32.370 And before they actually weren't right, they were a little above the ground. 08:32.380 --> 08:36.620 But now this works even with a nice big slope. 08:36.640 --> 08:43.150 So, for example, I'm just going to take about three of these three by three. 08:43.150 --> 08:46.570 So a grid of three by three big squares. 08:46.810 --> 08:51.610 I'm going to right click and I'm going to go to group Control G. 08:51.640 --> 08:52.680 Will do this. 08:52.690 --> 08:58.660 So now we have one big floor and I'm going to angle this floor a bit. 09:00.630 --> 09:02.550 45 degrees is a bit much. 09:02.550 --> 09:09.120 I'm going to choose a snap increment of ten and we'll do just ten for now. 09:09.330 --> 09:11.010 And let's play test. 09:12.260 --> 09:16.340 And as you can see, these are all on the ground. 09:21.250 --> 09:22.120 Perfect. 09:22.690 --> 09:26.110 I can even go into detach mode. 09:27.600 --> 09:29.640 And look at this a little closer. 09:30.910 --> 09:34.810 And we can see that we're always getting spawn points on the ground. 09:35.260 --> 09:36.100 Perfect. 09:36.100 --> 09:36.670 All right. 09:36.700 --> 09:43.450 Now, I don't really want this tilted, so I'm just going to move it back to how it was. 09:47.670 --> 09:53.130 And it's looking like I'm going to have it just off by a little bit. 09:54.210 --> 09:56.730 I'm just going to bring it up a little. 09:57.180 --> 10:00.030 It won't be perfect, but that's fine. 10:00.800 --> 10:08.480 And in fact, I can take the adjacent tile and take its location, Z, which is zero. 10:08.900 --> 10:13.480 And I can just take this one and set the location Z at zero. 10:13.490 --> 10:14.270 Perfect. 10:14.810 --> 10:16.610 Okay, so this is looking great. 10:16.640 --> 10:23.120 We now have a nice algorithm and it's asynchronous for spawn locations. 10:23.150 --> 10:30.410 Now we need to actually spawn things at those locations and that is one of our next steps. 10:30.410 --> 10:32.060 So we'll handle that next. 10:32.090 --> 10:33.260 Excellent job. 10:33.290 --> 10:34.340 I'll see you soon.