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Hello again.

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In this lecture, we're setting up a follow camera so that we can drive our car around to all the different

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parts of our world.

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Let's get started.

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Just going to roll up my game objects here.

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So that's a little less cluttered looking.

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Click on the main camera.

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You can see if we hit W to access our move tool.

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If we move around in our scene view, this is moving the location of the camera.

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You can see that this is how it will look if our camera is moving around as we drive, that's exactly

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what we want.

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What we want to do is say wherever the car is, say the cars over here at the position 13 five.

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Then we also want the camera to be able to that position at 13 five so the car stays right in the middle

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of the screen.

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Now, just one little caveat in the future will work with something called cinema screen, which will

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give us another option for creating a flow camera.

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But for now, I want to show you the way to do it with code so that you have that coding knowledge.

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Okay.

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So what we need to do is hop down into our assets directory, right click, create a C-sharp script

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and we're going to call this flow camera with Uppercase F and Uppercase C, and now let's open that

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up and we'll see.

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As always, we have the default start and update methods.

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All good so far.

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So let's ask ourselves, first of all, where are we going to put this script and what are we going

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to follow?

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Where we put the script is very important in terms of saying we are moving or changing or doing something

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to this particular thing.

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And this instance we want to move the camera.

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So it's best to put the script on the camera because we're doing we're moving that.

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So that's the first thing.

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So we're going to say this particular thing's position is going to move around in the world and its

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position is going to move around in the world to match this particular thing's position.

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So just undo those.

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So in here, I'm just going to write this as a note right at the top here.

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I'm going to say the this thing's position.

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In other words, the camera should be the same as the car's position so that we know what we're doing

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in this script.

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And then I'll jump back over into Unity.

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And before I forget, because often I do, I'm going to click on the camera and then just drag the follow

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camera script onto the camera.

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So we know it's there, the functionality is there.

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Well, I know I'm not going to need start because what we're going to be doing is going to be happening

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every single frame.

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So I'm going to remove start.

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I'm also going to remove this comment about what update does, because we know that pretty much by now.

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And in update, I'm going to put some code in here.

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We're going to start off by saying, what do we need to be accessing?

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Well, we need to access this particular game object.

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So this camera game objects transform and its position on the transform.

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So to do that, we start by typing transform dot and then what are we accessing within there?

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We're accessing the position so the value of the position and we want to be changing that or updating

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that to be the same as the value of something else.

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Well, this is where we need to create a reference so that unity knows what the heck we're talking about

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and what we're pointing at.

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Just a quick note on creating a reference, because we talk about creating references a lot.

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If we want to access or change, all call or pretty much do anything to anything in our game other than

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this game objects transform.

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We need to create a reference.

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So just to make that really super clear, this game object is the camera because we put this on the

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camera.

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So this is the game object.

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The main camera is a game object and we can access the transform because we get that for free.

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We don't need to go and make a reference to that.

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We don't need to point to that because it knows automatically, Hey, if you're changing the position

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of something, I'm pretty sure you're changing the position of me.

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So that part's for free.

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That's cool.

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But everything else we need to create a reference to.

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So in other words, we need to tell unity what the thing is that we're referring to.

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If we wanted to access this camera component, if we want to access the car, we want access the house,

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the rocks, anything else we need to say?

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I'm referencing this.

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I'm telling you, I want to access this.

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So there's a bunch of ways to do this.

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We'll look at one in this particular instance, and that is creating a serialized field that we can

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point to in the inspector.

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So let's do this together.

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Let's start by creating a serialized field.

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That means it's available in the inspector.

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We can see it in the inspector and then it's going to be of type game object.

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So we want to be accessing the car, the car game object, the whole thing and saying where is a position

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and we're going to call it say thing to follow because we want the camera to follow this particular

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thing.

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Now if I save that, jump back over into unity, look at where we've got our camera follow script and

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I'll just roll up a couple of these other components so they're not getting in the way.

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Just camera.

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And you can see on our follow camera script, if I saved over here, did I save?

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So Unity is not happy with me because I was half way through writing a line and then I sidetracked to

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tell you some theory.

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So I'm just going to comment out that line that I was half way through writing and nudity I think will

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calm down.

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Okay, cool.

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Rick.

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Yes.

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Now I'll let you do what you're trying to do.

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Okay.

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Now you see on our follow camera, we have this thing to follow and we've got a field just here.

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And by clicking on the little selector next to this.

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So just there we can click on.

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Seen.

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This will show us all the things in our scene we have access to.

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And if I scroll around, I should be able to find cruisy mic drive, double click on Cruisy Mic Drive,

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and now we have a reference.

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So we're saying this is the thing I'm interested in.

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This is now stored within the variable called thing to follow.

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I could have also just dragged it from the scene drag, drag, drag, drag and dragged it over into

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the box like that.

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That's another way that we could have created that reference.

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But now we're creating this reference to our player or to our vehicle.

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We jump back over into our script and we can say, Just uncomment my transform position.

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What do we want this to be?

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We want the position of the camera to equal the position of the thing to follow.

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And the way we write that is saying, let's first access the thing to follow.

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And then what do you think comes next thing to follow?

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Dot Transform.

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Okay, what's the next bit on this?

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Position.

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And then we do semi-colon and save.

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Now, I know that this is not quite going to work, but I'll show you what's going to happen here.

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When I click on play, the camera position will be exactly the same as the card position.

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So we'll click on play.

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Look what happens over here in our thing.

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It goes green.

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And that's a case of what?

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Why is it doing that?

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Well, while we're still in play mode, I'll click on the 2D button over in my scene view, scroll around,

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see if I can find my camera.

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So double click on the camera and you can see it's literally exactly the same place as the player.

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But that's no good because it means it's right on top of it.

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We need some distance.

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We need to be able to push it forward or push it backwards.

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And it won't let me do this in play mode because it's saying, no, you told me to be right on top of

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the car and I'm right on top of the car.

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So we need to give ourselves a little offset.

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And you can see when we're not in play mode that the camera is back a little bit.

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And it doesn't matter how close or how far when we're in this 2D view, it's going to keep exactly the

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same position.

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But if we go too close point, then all we're going to see is the the background and we're not actually

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going to see our scene.

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So what do we need to do?

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Well, we need to say follow the position of the car.

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Exactly.

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But stay back a little bit on what's this over here on the Z axis.

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So move back a little bit on the Z axis.

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The way we do that is just by saying go to the exact position of the car, plus a little bit extra on

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Z or in this case, you can see it's minus that's changing as I push it further away from the car,

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it's the minus direction.

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So when you say minus, I'm just going to say ten for now because that seems an okay spot.

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So just go to the car minus ten on the Z axis.

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How do we do that?

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Well, we've got our formula here.

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And if we mouse over position, we can see that position is a vector three.

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So we can't just get there and say plus minus ten or in this case it would be minus ten.

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It's like, I don't know what on earth you're talking about here, Rick.

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And we also can't say plus, let's see, zero on the X is zero on the Y and minus ten on the Z.

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It's also saying, what?

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What are these numbers?

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You're going to help me out here.

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So there's a way we can do this by saying we want to add a vector three, which is X, Y and Z, sort

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of vector three is into our current vector three.

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And to do that, we need to use the new keyword and then type vector three.

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So that unity knows.

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Oh, okay.

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You want me to add something that's a vector three to this.

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What do you want to add?

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And in here we can say zero, comma, zero, comma minus ten.

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And of course, those clever cookies of you would realize that we can also say minus plus ten.

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But for me, because I'm moving the camera minus ten on the Z axis, it makes sense to leave the minus

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ten just in here.

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And normally I'd say don't have any numbers right down in the middle of your code because if you need

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to change something, it's going to take a while to find this number and know what's going on.

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But I'm very, very confident that we're never, ever going to change this number just here.

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It's fixed, it's done.

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So I'm going to leave it forever.

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So I'm okay leaving this down in the middle of the code and forgetting about it.

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But like I say, if this was information that you might want to change at some point, then we'd need

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to create a variable and store that as a variable and do that a slightly different way.

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But we're not going to do that for the moment because we don't need to.

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So let's go have a look at what's going on in our game here.

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I've still left everything in 3D mode in the scene so we can see what's happening.

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Click on play, drive around and you can see that we're being followed around and we've got our nice

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distance of minus ten on the Z axis.

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We're staying away from the car, so it's perfect.

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I'm just going to get out of play mode, pop that back into two D There's one last thing I'm going to

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do in here.

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You might not be seeing any issues just yet, but we could get some issues with our camera being jittery,

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and we probably will in the future as we add more stuff in here.

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And that's because we will get a little bit of a conflict where the game says, I'm going to move the

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camera and I'm going to move the car.

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But sometimes I'll move the camera a little bit slower than the car, a little bit earlier than the

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car, because we haven't said specifically exactly when it should happen.

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So this brings me to an opportunity to talk to you about the unity execution order.

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And what that is, is all of the things that unity does when we push play.

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And then on every single frame that our game is running, there's a lot going on, a lot we don't need

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to know about.

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That's happening behind the scenes.

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But we know we've already played around with the START method or the START function when we click play,

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this is part of the initialization.

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In other words, starting things happening.

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There's also another method we could be calling called a wake.

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This is another callback that happens even before start.

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So if you need something to happen in the very instance, the very, very first thing that happens awake

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is going to be better than start.

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But generally START is okay for us and then we have our physics loop.

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So again, you don't need to understand all the aspects of this, but just know that physics is being

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calculated at a different rate to a lot of the other things in our game, such as our game logic.

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Physics is fixed and the reason it's fixed is so that there can be predictability with physics.

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If physics was calculated too much, it might be too intensive for the game.

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So physics is often requires a lot of calculations.

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So within unity, physics runs with its own loop and update can be a little bit different sometimes.

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Okay.

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And then what we also see within the general update.

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So here's our update here.

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This is happening on every frame and we get more.

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Frames on a faster computer and less frames on a slower computer, but it's still running through update

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and we haven't hear something called Late Update, which means with this whole update cycle, all the

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things that are happening on update, each frame we can say actually not do this as the very last thing

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that happens in the game logic, the very last update thing.

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And then there's a few other things in here that we'll explore throughout this course.

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But for the moment, we don't need to look at all these various things just to get the concept.

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There's a lot of things going on and they can happen at slightly different times.

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So if we jump back in here instead of placing our camera movement in update, if we place it in late

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update, which is just a case of popping in late in front of update, and that will change this whole

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thing from update to late update.

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Now we can guarantee that our camera will absolutely follow our car smoothly because we know it's not

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going to be fighting with the car in terms of what's my position and where are you and where am I?

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Let's just check.

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This works.

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I'll look a little bit silly if it doesn't work.

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When I click on play I can as we drive around.

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00:11:53,600 --> 00:11:54,410
That should be nice.

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Unless I bump into a tree.

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Should be nice and smooth because we now have things in late update.

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00:11:59,330 --> 00:12:00,020
Okay, cool.

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So that's what I wanted to show you.

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I wanted to get the camera working and just have a little bit of a conversation about the unity execution

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order, specifically that we need to put our camera in late update so we don't have the jitteriness.

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Great work.

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I'll see you in the next lecture.