1 00:00:04,340 --> 00:00:05,480 ‫Hello and welcome. 2 00:00:05,480 --> 00:00:10,550 ‫In this lecture, we're going to be learning to draw debug spheres in our scene so that we can visualize 3 00:00:10,550 --> 00:00:13,520 ‫different f vector locations in space. 4 00:00:13,520 --> 00:00:15,830 ‫Let's dive in and see how this works. 5 00:00:16,690 --> 00:00:22,510 ‫It's a very soon we're going to want to call our grab component at location with a rotation. 6 00:00:22,510 --> 00:00:28,660 ‫For this, we're going to need to know a couple of things which component we're trying to grab the location, 7 00:00:28,660 --> 00:00:32,200 ‫the rotation, in this case, the bone name we can happily ignore. 8 00:00:32,200 --> 00:00:35,110 ‫But we do need to know these other things. 9 00:00:35,320 --> 00:00:40,480 ‫So when it comes to the rotation, this is pretty straightforward because we can just take the rotation 10 00:00:40,480 --> 00:00:41,710 ‫of our component. 11 00:00:41,710 --> 00:00:43,960 ‫When it comes to the component, that's also quite straightforward. 12 00:00:43,960 --> 00:00:49,960 ‫All we have to do is take the component we collide with when when we're doing our sphere trace. 13 00:00:49,960 --> 00:00:54,340 ‫Now, the location, on the other hand, is a little bit more tricky because we don't just want to take 14 00:00:54,340 --> 00:01:00,580 ‫the location of the actual component, because I might be looking at it here, I might be expecting 15 00:01:00,580 --> 00:01:02,080 ‫to grab it by its head. 16 00:01:02,080 --> 00:01:06,580 ‫But if you see the root of this object, it's actually down near the base. 17 00:01:06,580 --> 00:01:09,280 ‫So it can lead to results that are a bit strange. 18 00:01:09,280 --> 00:01:17,110 ‫I grab it up near the top, near the wings, and it will then move the gargoyle up and float too high 19 00:01:17,230 --> 00:01:19,780 ‫so it doesn't feel right if you do it that way. 20 00:01:19,780 --> 00:01:21,910 ‫I've tried and it's just a bit odd. 21 00:01:22,300 --> 00:01:29,920 ‫So what we're going to do is we want to find where we hit this gargoyle when we do our sphere trace. 22 00:01:29,920 --> 00:01:35,680 ‫If we go over to our grab of CP, there's actually a couple of options in our hit result for getting 23 00:01:35,680 --> 00:01:37,750 ‫some vectors of location. 24 00:01:37,750 --> 00:01:44,230 ‫So if you do hit result dot and then hit a control space, you can see a bunch of different things in 25 00:01:44,230 --> 00:01:44,890 ‫here. 26 00:01:44,950 --> 00:01:47,050 ‫You can see that one of them is the component that we've hit. 27 00:01:47,050 --> 00:01:48,790 ‫We will be using that later on. 28 00:01:48,790 --> 00:01:53,860 ‫There is an impact point that could potentially be the interesting one. 29 00:01:53,860 --> 00:01:55,840 ‫There's also a location. 30 00:01:55,840 --> 00:02:01,360 ‫So to figure out whether it's the impact point or the location that I want, ideally we'd have some 31 00:02:01,360 --> 00:02:06,910 ‫way to visualize this in the world, visualize the point that we are trying to see. 32 00:02:06,910 --> 00:02:12,850 ‫And fortunately there is in the same include file that we found our drawing a debug line. 33 00:02:12,850 --> 00:02:18,550 ‫There is a draw debug sphere function as well and it has a lot of the same parameters. 34 00:02:18,550 --> 00:02:22,300 ‫You need a world as the first parameter, the center of the sphere. 35 00:02:22,330 --> 00:02:26,920 ‫The radius is a float, the number of segments that the sphere should have. 36 00:02:26,920 --> 00:02:29,950 ‫So we'll see what this means when we actually draw it. 37 00:02:29,950 --> 00:02:35,680 ‫Then there's a color and then whether it should persist in the scene and for how long, etc. So let's 38 00:02:35,680 --> 00:02:38,710 ‫have a go at drawing this sphere. 39 00:02:38,710 --> 00:02:46,660 ‫And initially I'm just going to use it to draw a sphere at the end point of our of our sweep. 40 00:02:46,720 --> 00:02:52,270 ‫So we're going to call draw debug sphere. 41 00:02:52,300 --> 00:02:56,500 ‫We don't have to include anything new because we've already got draw debug line in here. 42 00:02:56,650 --> 00:03:01,420 ‫Get World is going to be the first argument then the center of this sphere, which is going to be the 43 00:03:01,420 --> 00:03:03,850 ‫end vector, the radius. 44 00:03:03,850 --> 00:03:08,800 ‫I'm going to give it ten centimeters radius, I'm going to give it ten segments as well. 45 00:03:08,920 --> 00:03:12,100 ‫And then I'm going to have an F color this time. 46 00:03:12,100 --> 00:03:13,060 ‫Let's give it something different. 47 00:03:13,060 --> 00:03:17,830 ‫F color, colon, colon, maybe a blue sphere this time, persistent lines. 48 00:03:17,830 --> 00:03:21,700 ‫I do want this to be true because we call grab once, not every tic. 49 00:03:21,700 --> 00:03:25,060 ‫So I'm going to set this to true then the lifetime. 50 00:03:25,060 --> 00:03:31,750 ‫I'm going to set the sphere to last for 5 seconds and then the rest is less important. 51 00:03:31,750 --> 00:03:37,450 ‫I'm going to put a semicolon at the end of the line and recompile if we go ahead and hit play after 52 00:03:37,450 --> 00:03:44,020 ‫it's finished compiling and we'll move back a little bit from the gargoyle and I'm going to left click 53 00:03:44,020 --> 00:03:48,940 ‫and you can see the sphere appearing four meters in front of where I'm looking now. 54 00:03:48,940 --> 00:03:54,550 ‫I thought it would persist for 5 seconds, but actually what I need to put in here is not that persist 55 00:03:54,550 --> 00:03:59,560 ‫is true because that basically ignores the lifetime entirely and just keeps them around forever. 56 00:03:59,560 --> 00:04:03,490 ‫So if we put in false and then the time of 5 seconds. 57 00:04:03,490 --> 00:04:08,200 ‫So I just made a mistake there, which is easy to do and easy to misinterpret documentation and then 58 00:04:08,200 --> 00:04:10,810 ‫we go ahead and hit play in our game. 59 00:04:11,230 --> 00:04:16,870 ‫And if we create one of those spheres after 5 seconds, it disappears again. 60 00:04:16,870 --> 00:04:19,840 ‫So it won't be cluttering our world for too long. 61 00:04:19,840 --> 00:04:24,970 ‫So let's challenge you to figure out which location we need from our hit result. 62 00:04:24,970 --> 00:04:32,440 ‫Draw a debug sphere for each of them, the hit result location and the hit result impact point and use 63 00:04:32,440 --> 00:04:38,350 ‫different f colors to display it and make it clear which one is which and what's the difference? 64 00:04:38,350 --> 00:04:40,500 ‫Which one do we think we might need? 65 00:04:40,510 --> 00:04:42,460 ‫Pause the video and have a go. 66 00:04:45,760 --> 00:04:46,390 ‫Okay. 67 00:04:46,390 --> 00:04:47,320 ‫Welcome back. 68 00:04:47,320 --> 00:04:53,650 ‫Let's go back into the code and go down into our if statement where we've got a hit marked out. 69 00:04:53,650 --> 00:04:55,930 ‫So we will have some sort of hit result. 70 00:04:55,990 --> 00:05:06,370 ‫And just before we get hold of the actor, what I'm going to do is draw debug sphere using Get World. 71 00:05:07,000 --> 00:05:15,670 ‫And the first location we're going to draw is the hit result location going to go for ten radius, ten 72 00:05:15,670 --> 00:05:24,670 ‫segments, f color, colon, colon green this time and persistent lines is going to be false and the 73 00:05:24,670 --> 00:05:25,510 ‫lifetime. 74 00:05:25,510 --> 00:05:31,240 ‫Let's make it 5 seconds and then let's copy this line because we want almost exactly the same thing, 75 00:05:31,240 --> 00:05:32,650 ‫except we want to change out. 76 00:05:32,650 --> 00:05:36,070 ‫Hit result location for hit result dot. 77 00:05:36,950 --> 00:05:39,940 ‫Impact point and the color. 78 00:05:39,950 --> 00:05:45,920 ‫Maybe we'll switch that out to be read so that we know the difference between the two green and red. 79 00:05:45,950 --> 00:05:49,010 ‫Let's compile and head over into the editor. 80 00:05:49,040 --> 00:05:50,360 ‫Let's hit play. 81 00:05:50,570 --> 00:05:55,670 ‫And you see that when I don't actually hit anything, I just get this blue sphere. 82 00:05:56,060 --> 00:05:59,380 ‫And if I go up to the gargoyle, look at the gargoyle and try and hit it. 83 00:05:59,390 --> 00:06:02,690 ‫Okay, we've got two very different points here. 84 00:06:02,720 --> 00:06:05,990 ‫The green one is quite far away from the gargoyle. 85 00:06:06,020 --> 00:06:08,300 ‫The red one is much closer. 86 00:06:08,300 --> 00:06:09,660 ‫So what's going on here? 87 00:06:09,680 --> 00:06:15,650 ‫Well, if we look at the hit result documentation and come down and have a look at what location is 88 00:06:15,650 --> 00:06:23,510 ‫meant to be, you can see a discussion here, that location in world space where the moving shape would 89 00:06:23,510 --> 00:06:28,490 ‫end up against the impacted object if there is a hit. 90 00:06:28,490 --> 00:06:34,740 ‫And if I eject and pause for a second to see what these points actually look like, you can see that 91 00:06:34,790 --> 00:06:37,550 ‫Green One does indeed match that description. 92 00:06:37,550 --> 00:06:45,200 ‫We have a one metre radius sphere that we are projecting or sweeping towards this gargoyle and it would 93 00:06:45,200 --> 00:06:52,040 ‫hit the gargoyle as soon as it gets to this green point here, because that's about a metre radius around 94 00:06:52,040 --> 00:06:57,350 ‫it, whereas the impact point tells us where that sphere hits the gargoyle. 95 00:06:57,380 --> 00:07:02,270 ‫Now, that is much more likely to be where we want to grab it because it's actually on the gargoyle. 96 00:07:02,270 --> 00:07:08,030 ‫If I grabbed it over here, the gargoyle would rotate and spin around some point randomly in midair 97 00:07:08,030 --> 00:07:09,980 ‫and not look like we're grabbing it at all. 98 00:07:09,980 --> 00:07:15,140 ‫Whereas around this red point it looks like I've just grabbed it by the wingtip and that would look 99 00:07:15,140 --> 00:07:15,970 ‫natural. 100 00:07:15,980 --> 00:07:16,520 ‫Great stuff. 101 00:07:16,520 --> 00:07:21,710 ‫So in this lecture, we have learned a little bit more about what's available from a hit result, and 102 00:07:21,710 --> 00:07:26,640 ‫we've learned how to draw some more debug objects in our scene. 103 00:07:26,660 --> 00:07:28,220 ‫I'll see you in the next lecture.