WEBVTT 00:07.840 --> 00:08.780 Welcome back. 00:08.800 --> 00:14.170 In this video we're going to find out how to fix this pesky little problem with our firebolts. 00:14.440 --> 00:16.870 Sometimes they don't explode. 00:16.900 --> 00:23.950 Now what happens is, if we're launching a Firebolt at an enemy, and that enemy just happens to die 00:23.950 --> 00:30.220 before the Firebolt gets there, while the Firebolt still homes in on its homing target, which is now 00:30.220 --> 00:31.000 gone. 00:31.030 --> 00:32.680 Let me show you what I mean. 00:34.250 --> 00:35.090 There we go. 00:35.090 --> 00:39.620 So the enemy died and the Firebolt floats there. 00:39.620 --> 00:42.350 And after the enemy sort of perishes. 00:42.380 --> 00:43.250 Look at that. 00:43.250 --> 00:48.800 There's really no homing target for it to go to, and that's annoying. 00:48.890 --> 00:50.570 Now there's a fix to this. 00:50.600 --> 00:52.700 We can fix it in tick. 00:52.730 --> 00:54.230 Wait, wait, wait a minute. 00:54.260 --> 00:55.730 Did Stephen just say tick? 00:55.760 --> 00:57.290 Isn't that bad practice. 00:57.320 --> 00:59.450 Tick is always bad practice, right? 00:59.570 --> 01:06.990 Well, not if you can set the tick rate to a low value so an actor doesn't take very often. 01:07.010 --> 01:10.000 Let's go into ability, system or abilities. 01:10.010 --> 01:13.610 Fire Firebolt and get our Firebolt. 01:13.880 --> 01:20.800 Now an actor that ticks less often is a lot more performant. 01:20.810 --> 01:25.880 And if we have Firebolt self selected right here, we have a tick interval. 01:26.030 --> 01:29.630 Now if it's set to zero well that's going to be the maximum. 01:29.630 --> 01:38.450 And let's just see what that looks like by drawing a debug sphere at its location we're going to get 01:38.480 --> 01:39.770 actor location. 01:41.720 --> 01:47.810 And I'm going to promote this to a variable called location this frame. 01:51.200 --> 01:53.030 And I'm going to set that in tick. 01:53.030 --> 01:57.230 And I'm going to use that to draw a debug sphere with a radius of five. 01:57.260 --> 02:01.130 It's going to be white and its duration can be five seconds. 02:01.130 --> 02:04.760 So let's see how often that tick looks like. 02:06.990 --> 02:09.480 That's a whole lot of spheres, right? 02:09.810 --> 02:18.060 Now, if we set our tick rate, which is this tick interval here to 0.1, that's ten times per second. 02:18.090 --> 02:22.320 That's a lot less than 60 or 120. 02:22.680 --> 02:25.500 Modern computers these days it's 120. 02:25.500 --> 02:29.580 So ten times per second is not often at all. 02:29.610 --> 02:31.590 Let's check it out now. 02:33.560 --> 02:35.210 See, that's a lot less. 02:35.210 --> 02:40.340 And we could even put this down even more to say 0.2. 02:40.370 --> 02:43.460 That's five times per second. 02:44.320 --> 02:46.720 I mean, that's not very long now. 02:46.750 --> 02:52.960 My point is that we can use tech and we can see if that fireball has stopped moving. 02:53.140 --> 02:55.180 That's the approach I'd like to take. 02:55.180 --> 02:58.600 So I'm going to take that draw debug sphere, set it off to the side. 02:58.630 --> 03:00.970 We're going to set location this frame. 03:00.970 --> 03:08.260 But I'm also going to promote that get actor location to a variable and call this one. 03:08.290 --> 03:10.840 This will be the location last frame. 03:10.840 --> 03:13.720 So location last frame. 03:13.900 --> 03:18.190 And I'm going to set location last frame equal to. 03:19.350 --> 03:22.170 Location this frame before updating. 03:22.170 --> 03:24.690 Location this frame like that. 03:26.080 --> 03:31.420 And now we have this frame and last frame we can see the difference between them. 03:31.420 --> 03:36.190 So I'm going to take location this frame subtract location last frame. 03:36.190 --> 03:40.390 And we can get the vector length of this. 03:40.390 --> 03:44.050 And that will tell us how far apart these locations are. 03:44.290 --> 03:47.380 So if we get a vector length we can check it. 03:47.380 --> 03:50.980 And we can have a minimum we can have a threshold. 03:50.980 --> 03:57.250 So let's go ahead and make a variable called min distance per frame. 03:57.430 --> 03:59.680 This can be a float. 03:59.710 --> 04:01.060 We can compile. 04:01.060 --> 04:03.730 And we can set this to a low value like ten. 04:03.730 --> 04:12.130 And we can check if this vector length is less than or equal to min distance per frame. 04:12.130 --> 04:17.050 If that is the case, well, let's do a branch and decide what happens. 04:17.080 --> 04:21.040 What I'd like is for the projectile to go kaboom. 04:21.040 --> 04:28.840 So spawn sound at location at and let's just see what our impact sound is here. 04:30.400 --> 04:32.320 It's this sound effect right here. 04:32.320 --> 04:41.050 So I'm going to set that the location we have location this frame and then spawn system at location. 04:42.200 --> 04:46.700 And again, I want to see what impact effect we have here. 04:46.700 --> 04:47.660 It's this one. 04:47.660 --> 04:51.530 And actually we have to we're not using this one. 04:51.530 --> 04:57.110 So if we use this one we could change it up a little bit, change how it looks and then we'll know for 04:57.110 --> 05:00.500 sure if that is what is being spawned. 05:00.530 --> 05:03.800 So we'll do that at location this frame. 05:06.510 --> 05:07.470 Like so. 05:07.470 --> 05:09.780 And then we'll destroy the actor. 05:14.630 --> 05:19.340 Okay, now this explosion, I'm going to just change a bit. 05:19.370 --> 05:23.040 You can uncheck these emitters to change what it looks like. 05:23.060 --> 05:24.560 I'm just going to change it. 05:24.560 --> 05:26.680 So it just does one little thing. 05:26.690 --> 05:27.980 Perhaps just the ring. 05:29.860 --> 05:31.990 And maybe the sparks black. 05:33.530 --> 05:34.610 That's pretty different. 05:34.610 --> 05:35.870 So I'm going to save that. 05:35.870 --> 05:41.180 And now with our fix in place let's see what happens. 05:49.680 --> 05:52.920 And we definitely saw them explode. 05:55.270 --> 05:59.350 See, it hovered for a second and then it exploded, which actually looks pretty cool. 05:59.380 --> 05:59.610 See? 05:59.620 --> 06:03.730 Hover, explode and that little hover for a second. 06:03.760 --> 06:11.920 Of course, you can change the tick interval to a smaller value, but 0.2 is fine. 06:11.920 --> 06:13.870 It's only five times per frame. 06:13.870 --> 06:16.060 That is not that much at all. 06:16.060 --> 06:21.730 And of course all of this is something that could be moved into C plus plus as well. 06:21.740 --> 06:24.430 It's not going to be that much more performant. 06:24.880 --> 06:27.100 I'm just going to collapse it. 06:28.130 --> 06:34.520 To a function and call this make go kaboom. 06:36.530 --> 06:38.540 And we'll do that in event tech. 06:38.750 --> 06:42.560 We'll say make go kaboom if no move. 06:43.400 --> 06:45.980 Make go kaboom if no move. 06:46.530 --> 06:47.850 Perfectly descriptive. 06:47.850 --> 06:48.240 Right? 06:48.240 --> 06:49.230 Perfectly. 06:49.260 --> 06:50.040 All right. 06:50.040 --> 06:52.710 So that takes care of that issue. 06:52.710 --> 06:58.250 And of course, you don't have to play the weird little black tar looking explosion. 06:58.260 --> 07:00.390 You can play the regular explosion. 07:13.160 --> 07:14.120 Boom boom. 07:14.150 --> 07:14.930 Awesome. 07:14.930 --> 07:18.530 So yeah, we don't have to play that weird explosion. 07:18.530 --> 07:20.750 We can play our impact effect. 07:23.610 --> 07:27.270 So I'm just going to browse to that and use that system. 07:28.080 --> 07:33.120 And with that we have a very nice performant solution. 07:33.600 --> 07:36.150 I'll see you in the next video.