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In this lecture we're working with if statements and tags so that if we drive over something that is

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tagged as customer, we print to the console package picked up and if we drive over something tagged

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as customer, we say package delivered.

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So let's get started.

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Let's start by doing a little bit of repurposing.

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I'm going to click on my object here that was just called Square and I'm going to rename this to B package.

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So this is now the package we're picking up and just reshape it a little bit.

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So there we go.

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It's a bit of a square package.

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Doesn't quite look like the thing Amazon would deliver, but there we go.

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Well, pop it somewhere in our world so we can drive over it, put over near the player so it's nice

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and quick to find.

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Excellent.

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That's step one.

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Now, step two, I'm going to be using my collision script because that's what we've been dealing with

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on trigger enter and on collision enter.

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But collision doesn't make sense anymore.

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So I want to show you how we rename a script because it can be a little bit messy.

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First of all, I'm going to click on where it says Collision one more time or you can hit F2.

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Let me just check that works f to set a collision.

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I'm going to name this delivery because that makes more sense.

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We're dealing with the delivery system.

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So I'm going to hit enter now.

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I'm going to open up delivery.

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And you can see here, it's still public class collision.

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So it thinks I am a collision class.

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I'm going to just highlight the word collision and change that to the word delivery, making sure we

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spell it exactly the same as the name of our dot CSS file I'm going to save.

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Now back over into Unity.

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And the last step is to click on Cruise Image Drive and we can see here that the delivery script has

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automatically been updated from collision to delivery.

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Cool.

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So that should all work exactly the way we want to.

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Now, let me tell you a little bit about the logic of what we're going to do.

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I'm going to show you what happens when we drive over so when we trigger something to happen by driving

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over our package, I'm going to show you that.

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And I'm going to print out to the console a message that says something like, you picked up the package,

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but we only want to print that to the console if it's the package that we drive over.

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Because I'm going to give you a challenge later on in this lecture where I challenge you to make the

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customer.

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And if we drive over the customer, we want to print a different message.

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So we can't just say when you collide with anything, let's just have a look at our delivery script.

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It says, When you collide with anything or when you trigger anything, do a particular thing.

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But it's like, okay, well, when we when we have on trigger enter with one thing, we want to do one

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thing, but if it's on trigger, enter is something else.

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We want to do something else.

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How do we do that?

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The way we do that is with if statements.

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Let's talk about if statements just briefly here.

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So an if statement lets us check if something is true or not and then do something based upon the result.

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And then this is how the syntax looks in C-sharp we start with the if keyword and then in parentheses

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we have the thing that we want to know if it's true or not.

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So we need to write something in there saying, Is this particular thing true?

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And then in our code block we have what it is that we want to have happen if that thing actually is

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true.

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So for example, for me it might be if I'm hungry right now, then eat junk food while my wife isn't

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watching.

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That could be my if statement.

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You can tell what's on my mind at the moment and if I'm hungry turns out to be false.

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Then we don't even consider what's in the statement here.

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We don't even think about sneaking some tasty donuts while the wife isn't watching.

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It's a way of saying, if I'm hungry, do this.

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Otherwise do nothing.

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Okay, so let's start this process in here.

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Now I'll leave my on collision.

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Enter in there just in case we need it in the future, in case we bump into something, we might want

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to do something with that.

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But we're focusing the on trigger index triggers.

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We don't want to bounce into the package and the customer is going to drive over them.

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So in here we need to start out if statement and I'm just going to put a comment in here and write some

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pseudo code because we don't have everything we need yet to execute on this, but we'll write the general

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meaning of what we're doing.

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So if the thing we trigger is the package, then what do we want to do then?

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Print package picked up to the console.

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Now we can give this a little bit more structure by saying we'd have our curly braces and then we would

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have our print statement and then we would have our other curly braces.

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All of these are within the comments.

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You don't need to be typing this.

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I just want to type this so you can see exactly what we're doing.

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And the bit that we don't have is how do we know if it's a package or not?

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So let's have a chat about tags.

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Tags allow us to easily check in our code if something belongs to a particular category of thing and

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allows us to speed up that process of saying, Are you the package?

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Are you the package?

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Are you the package?

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So I'll show you how we go about doing that.

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We have our package.

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We're clicked on this game object and over in the top right of the inspector, you'll see Tag Untagged.

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At the moment it doesn't have a tag.

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It's like, I don't know what sort of tag you want me to be.

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No worries.

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When we click on the untagged area, we've got some default tags that already exist in Unity.

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Player is probably the main one that we would use in the future, but for now we're going to click on

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the ad tag and then you'll see Under Tags List is empty.

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Click the plus button in here.

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I'm going to type package as the tag uppercase P and then click on Save.

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Now we have package that hasn't assigned it yet.

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What you need to do is click on the game object again.

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You see it's untagged.

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Now I can go in.

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Select package, and we've tagged this game object as being of tag package.

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It's not a type package, it's just been tagged as package.

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Now we can jump back into our code and before I get rid of the comments, there's one other thing I

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want to show you in here.

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We talked about this one.

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We talked about the collision and the trigger that you can see where accessing or something's being

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passed into this.

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When it's cold, it's being passed in, it's giving us information about the other thing that we bumped

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into.

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So this is really cool.

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This delivery script is on our car, but when we trigger something or when we bump into something with

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collision, we know what it is that we bumped into so we can gather information from that.

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And in this case, we're going to say the other thing that we collided with, does that have a tag on

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it that says package?

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So that's what we'll do.

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We'll get rid of our comments here.

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We don't need those anymore.

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Thanks very much.

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Comments.

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Lots of squiggly lines.

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Cool.

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If we're going to access the other thing we bumped into by typing other dot and then it's as simple

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as saying tag, then we're going to use the double equals sign operator, which is a way of comparing

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the left and the right and saying, Are these two things the same?

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So we'd say equals equals.

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And then we're going to write in here quotation marks, capital P package, if I can spell it correctly.

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And this as soon as we use the equals equals operator, it's going to say, is it true or not?

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Does the left equal the right?

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We get a true or false value back from that.

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So this is going to say it's either true, yep, it's a package or the tag is not a package.

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And then in here, what do we want to do?

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Well, we will type in debug dot log package, picked up semicolon and save.

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Now let's jump back over into our game.

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Click on the console so that we can see if this is actually going to work or not.

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Click on play drive our car over to the package pip and it says Package picked up.

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Excellent.

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If you drive over it and over it, it's going to go up and up and up and up and up and up.

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So that's something we'll deal with in the future where we we get rid of the package after we've picked

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it up.

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For now, we can print out the message that we've picked up the package.

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So I've got a challenge for you.

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It's going to be a little bit more detailed, but I think you're ready for it is to set up our delivery

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location.

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So I'm going to call it the customer.

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It's probably just going to be a box or a circle or something.

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It doesn't actually need to look like the customer because we're going to drive over it.

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But I want you to create a customer that allows us to print delivered package to the console if we drive

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over it, similar to the way that we drove over our package.

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Now, if that's enough for you to go on, pause the video and jump in and take that on.

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Now, otherwise, I've got some hints for you.

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So if you don't need the hints, pause the video.

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But if you would like the hints, here they are.

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Create a game object that has a collider on it.

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If you can't see the object, check your sorting layer to make sure it's above the road set is triggered

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to true on the collider.

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Create a customer tag as we did with the package tag and assign it to the object and then print your

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message if we touch the customer object.

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So there you go.

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There's your challenge plus video.

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I'll see you back here when you're done.

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Okay.

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First step is get out of play mode.

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That's a good first step.

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And then right click, I'm going to create a 2D object will make a sprite.

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What should we make this?

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I'll make this a square as well.

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I'll just change its color.

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So we'll pop the customer over here.

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I'm going to increase the size of this a little bit.

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Just hit R and then grab the middle of it and scale it up for now.

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So it's nice and easy to see.

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We can change the graphics on this later on pretty easily.

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Change the color to maybe a blue.

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Now I'll rename this game object to be customer hit enter.

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I also need to create a tag so click on tag, add a new tag, click on plus and we will name this customer.

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Click on Save.

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Now back to clicking on customer the game object and tag this as customer the tag.

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Excellent.

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Now we need to go into our code.

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I think we've done all of this.

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We're going to create another if statement.

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So second if statement which will if other tag equals equals customer, then what do we want to do?

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Put in our curly braces, debug dot log package delivered semicolon and then save.

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Now I usually miss a step in these things, so let's see if I did or didn't miss a step.

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I'm going to click on play.

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Putt.

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Putt, putt.

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Drive over here.

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Yeah.

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Package picked up.

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Drive over here.

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Okay.

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So I have missed the step and I know what it is straight away because I've missed this step many times

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in my career.

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Do you know what it is?

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What has Rick done wrong?

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What mistake have I done?

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If I click on customer, I don't have a collision on here.

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How do I know I've bumped into it?

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So I'm going to add a box collider to DX.

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And then the very last step is to make sure that I click on is Trigger and then Save.

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Now click on play.

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That should have got it.

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So drive to drive over that one.

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Good.

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And then over this one.

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Excellent package delivered.

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Cool.

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So now we've got the fundamentals in our code of it knows.

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Oh, yeah, you went over a package and oh yeah, you delivered it to the customer, so.

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Excellent.

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So that's all for this lecture.

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I will see you in the next one.