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Following all the set up that we did in the last lecture.

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In this one, we're going to get our player shooting.

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Now the first step to this is to figure out where we want this shooting behavior to be written.

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So if we go into our prefabs and have a look at how our player is set up, we're going to be listening

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for On Fire as part of our player input.

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And if you remember when we were listening for On Move, we were doing that in the player script.

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So let's have a look at the player script just to remind ourselves of how we were doing that.

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And if we scroll down, we had this on move event which was listening for the input itself, so we could

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also listen for our On Fire event in here as well.

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However, we don't really want the actual shooting behavior to be part of this script because our enemies

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are also going to need to shoot back at the player.

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So let's put our on fire method in here to listen for when the player is pressing the fire key.

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And then later on we can use this method to set a variable within our shooter script to start that firing

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process.

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Before we do that, though, I've noticed we've still got a debug log in here for our on mode method.

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So let's delete that first just to clean things up a little bit.

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And then underneath this, let's write our on fire method.

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So just like the one above it, it's going to be void.

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We're going to call it on fire.

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And because we change the action type to be of type value, we can pass in a type of input value called

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value.

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And then in here we're going to be setting a boolean from our other script.

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We haven't written that script yet though, so let's save this up for now.

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And then on our player prefab, let's go down and add a new component called Shooter.

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If we open this up, let's now think about what this script is going to need to do.

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Well, the way I'm going to do it is I'm going to have the script instantiate some projectiles whenever

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that fire key is pressed.

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So to start with, let's clean up our comments, but leave our start and update method alone.

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For now, we're going to need a serialized field to hold the prefab for our projectile.

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So let's have a game object called Projectile Prefab.

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And when we create this projectile, we're going to want it to have a certain amount of speed and we're

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going to want it to live for a certain amount of time.

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So let's control these variables with serialized fields as well.

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We can have a float called projectile speed and I think a default value of around ten should be okay

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to start with.

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And we need a serialized build again of type float called Projectile Lifetime.

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And for this I think maybe 5 seconds should be okay.

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Finally, let's actually finish setting up that Boolean flag that we're going to need for our player

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script because this needs to be accessed from another script.

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Let's go ahead and make it public.

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Our public variable is going to be of type ball and we're going to call it is firing.

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And now with that set up, let's jump back over to our player script and just quickly finish off our

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on fire method.

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Before we do that, we're going to need access to our shooter script from within our player script.

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So right at the very top, let's add a new variable of type shooter and we'll call it the shooter.

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And then if we create an awake method to grab that component off of the object, we can say shooter

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equals get component of type shooter.

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Now back down in our on fire method.

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First of all, we can check whether we've got that shooter script so we can say if shooter does not

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equal null.

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In other words, did we find it attached?

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And if we did, we can set shooter is firing to be equal to the value dot is pressed.

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Now that's really all we need to do for our player script.

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So let's head back over into our shooter script and have a think about how we're going to start instantiating

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our projectiles.

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Well, for things like this, I'm quite a big fan of KO routines and we've seen KO routines once, so

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this is very good practice to try writing another one.

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Before we do that, let's set up the framework that this routine is going to sit in because we're going

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to control the starting and stopping of this routine within a fire method.

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This fire method is going to be checked every update.

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So let's write a dummy method called fire.

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And then under this we're going to write that method.

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So void fire.

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And this is where we're going to start that code routine.

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And since this routine is essentially going to allow us to fire continuously, it would make sense to

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call this routine fire continuously.

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So finally, let's put the bones of that routine in place as well to get rid of our red squiggly.

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And if you remember, a coyote has a return type of eye enumerator, and we're going to call this fire

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continuously.

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With the bones all set up.

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We're not going to worry about the red squiggly there for the moment.

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That's just because we don't have the return type set up yet.

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But before we go ahead and write that coating, let's just think about the logic in our fire method.

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The way this is going to work is that if our player script tells us that we are currently firing, then

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we want to start this routine.

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Otherwise, we want to stop our routine.

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To start our coating will be nice and simple.

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We're going to say that if is firing so that's controlled by that public boolean, then we want to go

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ahead and start our routine.

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Else.

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We want to stop our car routine.

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Now, how do we stop a routine?

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Well, there are a couple of options, depending on how brute force you want to be with it.

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One option is to just say stop or kill routines.

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This will indiscriminately stop any routine that's running.

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But it is kind of like taking a hammer to the problem, and we want to be a little bit more surgical.

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So the other option is to stop routine.

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And then tell it what coating to stop and to tell it which Curry team to stop.

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What we're actually going to do is when we start our routine, we're going to store this as a variable.

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So this is another really powerful thing that you can do with curry taint.

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If we head to the top of our class and create a new variable, this variable is going to be of type

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CO routine and we're going to call it our foreign CO routine.

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Then we can set this variable by again heading down into fire and where we're starting our routine.

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We just want to say that our firing routine is equal to that started routine.

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Then with that variable set in our block, we can stop our firing routine.

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Now, whilst this will do something, it isn't going to be quite what we want.

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So we will have to come back and adjust our if and our else statement, add some extra information in

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there.

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But before we do that, let's go ahead and actually write our code routine, get some projectiles instantiating

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into the world, and then we can see the flaws in this current setup and how we might fix it.

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And writing this routine is going to be a challenge for you.

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I want you to write the logic for our fire continuously routine, and this chi routine will loop indefinitely.

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So think about how to create an infinite loop intentionally.

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It will instantiate a projectile for every loop around this infinite loop.

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And we also want to set up the destruction of this instantiated projectile after the projectile lifetime

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has expired.

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And as a hint for this one, check out the overloaded versions of the destroy method that we've used

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before.

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Finally, we want to wait for the time specified by a variable we're going to call fire rate, and we

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haven't actually written this variable yet.

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So go ahead and add this one as well.

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So quite a big challenge with a lot of moving parts, but pause the video now and give it your very

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best shot.

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Okay.

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Welcome back.

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So the first thing I'm going to do is add our missing variable for our delaying of our routine.

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We're going to set this as a serialized field so we have some control.

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It's going to be of Type Float and we're going to call it the firing rate.

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And by default, let's set that to maybe around 0.2.

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Then down in our routine, we said we wanted this to loop indefinitely because we are going to be controlling

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the starting and stopping of our routine within our fire method.

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And to intentionally create an infinite loop, we can say while true.

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So inside of our infinite loop, we wanted to create a new projector.

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And for this I'm going to instantiate it directly into a temporary variable of type game object.

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And I'll call this the instance, and this is going to be equal to instantiate our projectile prefab.

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And while I'm here, I'm going to set the position to the transform dot position so it'll be created

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at the position of the player's ship.

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And because we've specified a position, we also need to specify a rotation and we can specify no rotation

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with Quaternions identity.

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Now this line is a little long, so let's break it up then.

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I said we wanted to destroy this instantiated object after its lifetime had expired so we can use the

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destroy method for this.

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The thing we want to destroy is our instance and we want to destroy it after the projectile lifetime

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has expired.

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Finally, we want to yield our routine and wait for the firing rate.

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Time to elapse so we can say yield return.

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Remember, routines always have to yield rather than just return.

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And we want to return a new wait for seconds of the firing rate.

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So let's give that a save and jump into unity to test out what happens.

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Like I mentioned before, this, if else block isn't quite what we need.

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So let's have a look at what actually happens in this circumstance before we go and fix it.

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First of all, let's reopen our play prefab and go down to our shooter script.

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This needs a projectile prefab.

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So let's drag in our projectile player.

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Then if we go ahead and hit play to test this out, we can still move around just fine.

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We are getting another reference exception, so we'll look at that in just a moment.

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And if we try on fire, we get a whole bunch of projectiles all getting spammed out at once and it's

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all going a little bit wrong.

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So let's come out of play mode.

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And before we fix that dodgy car routine, let's just have a look at the console log error and this

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is giving us a null reference exception saying that the routine is null.

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Now both of these problems are very easily fixed with our if else, block So let's have a look at what's

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happening.

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What we're doing is when we press the space bar we're setting is firing to true.

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And remember, fire is happening in our update loop.

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So it's being called every single frame.

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So when we hit our space bar, this is set to true.

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And then every single frame we're starting a new routine.

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The error in the console, on the other hand, comes from our else block in the time before we hit our

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space bar.

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So right at the beginning of the game, this variable is going to be null.

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So we're trying to stop a routine that hasn't been set.

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Now, how do we fix both of these problems?

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Well, the first step is to look at our if statement.

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What we need to say is that if we are firing and our firing co routine equals null.

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So if we haven't set this up already, i.e. we've not called start routine yet, then we're going to

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start firing.

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Once we've done that, once, this statement will be false.

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So even if we're continuously holding down the fire key, we won't continue to start more routines.

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So that should slow down our firing rate to the correct speed.

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And for the second one, what we're going to say is else if because we need to specify some conditions

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and we want to specify that we're not currently firing and our firing routine does not equal null.

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Now, this sounds fine in principle, but when we stop a routine like this, we're still going to have

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something in our firing routine variable.

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So to add to our elseif block, once we've stopped our routine, we're going to set our firing protein

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equal to null.

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So hopefully the logic checks out there and it all makes sense.

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Our projectiles aren't moving anywhere though, so let's make that on next priority and we're going

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to do this down in our routine.

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If you recall, our projectiles do have a rigid body attached.

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So what I'm going to do is once we've created the instance of our projectile, we're going to grab that

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reference to the rigid body, and then we're going to apply a velocity to it.

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So let's start by grabbing that reference to the rigid body, and so we can do a little bit of extra

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checking.

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We're going to store this in a temporary variable of type rigid body 2D, and we'll call this r b.

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Now we want to go ahead and grab the rigid body component off of our object so we can say instant dot,

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get component of type, rigid body, 2D.

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And for the extra checking that I was talking about, we're just going to say that if our rigid body

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are B does not equal null, then we're going to set the rigid body velocity.

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And to set our velocity, we need to give it a direction and a speed well for the direction we can use,

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transform, dot up.

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And if we hover over this, it says it's the green axis of the transform in world space.

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So to explain this in real terms, let's jump back over into unity and click on our player.

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And here we can see the green up arrow.

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So Transform Up is going to follow this green arrow.

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So back in our code we can take our transform up, which has a magnitude of one and multiply it by our

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projectile speed.

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So with that set, let's save that up and jump back into unity one more time.

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Let's jump into play mode.

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And as if by magic, we now have projectiles shooting at our enemies, and if we hit them enough times,

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then we can destroy our enemies as well.

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So we've now got a pretty solid game on our hands.

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If we hit the enemies, then we die.

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But we now have a way of fighting back and scoring some points.

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So congratulations on getting the player projectiles working.

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And in the next lecture, we're going to look at amending our code to get the enemies firing back at

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the player.

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So fantastic work and I'll see you in the next lecture.