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Rodeo.

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In this lecture, I'm going to be showing you a technique to stop our player being able to do this midair

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jump and fly off onto the screen.

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And the way we'll be doing that is using layers.

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We've already had a look at layers a couple of times.

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We've looked at sorting layers.

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So let me click on the platform tile map here.

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You can see under layer we've currently got default.

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That means the collision layer.

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I like to think of it as collision layer.

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If we go and click on Add Layer, you can see that we've got sorting layers which we've played around

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with.

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That's the visibility, what will be displayed first and displayed seconds so that our platforms are

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on top of the background.

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We've also got these other layers in here.

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The way we mostly use these is when we're looking at collision, but there's a few other usages.

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For example, layers are useful if you have the same functionality across multiple game objects.

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What do I mean by that?

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Well, if you want a whole bunch of things ignored by the camera or a whole bunch of things to be not

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clickable or a whole bunch of things like in our case, to be doing a collision check.

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And if we jump over to the main camera over here, you can see that the main camera uses this sort of

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collision for the culling mask.

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What's a culling mask?

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That's a way of saying what can you see or not see?

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The mask is where we group a bunch of things together.

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So if you see my little main camera view down here, our preview, you can see that we can see all our

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level and stuff.

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If I was to go into the culling mask and select on nothing, we'd see nothing, just the solid background.

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That is because everything has been culled by the camera.

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What we'll do, we'll look back on everything here.

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And so we could set up a new layer that said Only show through the camera only shows certain things.

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I only show, say the ground or the green things or the enemies or whatever.

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You can turn things on and off in the camera using this culling mask for us.

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We want a ground layer.

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So I'm going to click back on my platform's tile map just so I'm in the right ballpark, click on layer,

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add a layer, and then use a layer number six or wherever.

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It doesn't matter what number you attach this to, I'll create a ground with an uppercase G to keep

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that convention.

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So now that we've created ground, click back on the platform's tile map again and change the layer

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to be the ground layer.

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One thing we do need to have a quick look at here, if you go to edit project settings and find physics

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to scroll down, you can see there's a little matrix down here which says which things will collide

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with which other things.

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And you can see that we've got ground and that is lining up with default, our etc. We've got a few

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default kind of things in here.

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So if you go to uncheck something in here that would say this thing can't collide with that thing.

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So if we had another layer in here which was, for example, enemies, and if we unchecked the relationship

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between enemies and ground, then there's a chance the enemies would just drop through the ground and

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not actually collide.

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So if sometimes if you get a little bit of issue and you're like, why are things not bumping into each

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other?

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You might just want to come in and check that matrix, that collision matrix, just to make sure things

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are checked appropriately for us.

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For now, we're just going to have everything colliding because that's the way it's going to work in

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our game.

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But you could absolutely have something in your game where you say, Well, I want the player to be

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able to run straight through something and not bump into them, whereas I want the enemies to bump into

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those things so you can play around with your collision matrix that way using the layers.

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What are we going to do?

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Well, we're going to stop the player jumping any time they please that we're going to say only jump

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when you're touching the ground layer using Collider 2d dot is touching layers.

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Let's have a quick look at a couple of Unity docs.

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Collider 2D is touching layers.

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This is going to return a ball, which will be true or false depending upon whether or not this collider.

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So whether wherever we place this in our case, it's going to be on the player, whether the player's

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collider is touching any collider on the specified layer mask or not.

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So in other words, is it touching any of the colliders, all these many colliders we might happen to

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have placed on the ground layer?

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And the other doc is layer mask, target mask.

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And you can see here it returns the layer mask created from the layer names.

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So we need to know that we're dealing with the ground layer and the ground layer is going to generate

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a mask and we need to have a way of getting that mask.

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And so this all leads to a challenge where I'd like you to finish the logic to stop our player multi

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jumping.

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I've given you a lot of clues, but not the exact exact recipe for doing this.

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You will need to use the collider.

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2D is touching layers and you will also need to use the layer masking mask.

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You'll need to make sure that you're accessing the player's collider and also you'll need an if statement

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in there somewhere.

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So give that a go.

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Pause a video, take on that challenge.

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See you back here when you're done.

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First thing I'll do is to set up a reference to our collider.

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Now our particular collider on the player is a capsule collider.

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So I'll specifically say, let's find the capsule.

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Collider Capsule.

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Collider 2D is going to be the type and then we'll call this my capsule collider semicolon.

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And then in start we need to get our component.

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So my capsule collider equals get component.

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What's the type?

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It's going to be the capsule collider to dx parentheses semicolon.

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So we're looking at on jump and in here we've got some functionality.

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If you press the button, then you can jump.

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We could add in a you know, and add some more criteria.

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Or we could wrap all of this in a if statement that says, if you are not touching, then do these things

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or we can do it another way, which says if you're not touching the ground, then don't progress to

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any of this, just return.

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Don't do any of this stuff.

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So the way we're going to write that, to say, if I'm not doing a particular thing, what am I not

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doing?

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Well, if my capsule collider dot is touching layers and then which layers are we interested in?

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Well, this is where we need to use our layer mask, get layer masks, get mask.

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And then the particular layer we're interested in is ground within uppercase G.

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We remember that if you're not touching, then we could write it like this.

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Just simply return.

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That means get out of this method and don't go any further.

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I'm just going to tidy this up so it's a little bit easier to to read quickly.

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And I'll put all this on the one line so we can add return up here.

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Return.

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There we go.

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All on the one line.

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Let's save head back to unity, make sure that we have all the things hooked up.

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So the platform.

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Yep, that does say ground.

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That's cool.

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The player does have their capsule collider we'll click on play.

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We've got an error that's going to be Rick doing something dumb.

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And you know what?

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After pausing the video and messing around here for a while, I've discovered that I spelt something

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incorrectly.

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I need to spell is touching layers with an uppercase.

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I then saving jump back over into unity.

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My error should go away with a different sort of warning that says Rick.

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Make sure you check your spelling done to head click on play.

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Now let's see if our functionality is as we want it.

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I can jump jump but I can't jump over and over.

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Excellent.

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Despite tapping the spacebar a whole bunch.

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So there we go.

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We've stopped our player doing the extra jumps.

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You can only now jump when you are touching the ground.

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Okay, I'll see in the next lecture.