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Now that we've got our player moving around the screen, it's time to start thinking about adding some

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enemies.

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And the way we're going to do this is going to involve a few different scripts talking to each other.

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So before we just go ahead and start coding things up, let's actually talk about how our enemies are

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going to work and what script we're going to need.

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Now, our enemies themselves are going to have a few different requirements.

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They're going to need to be able to cause damage to the player, either through collisions or through

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shooting at them.

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And rather than just having a single type of enemy, we're going to have different enemies with different

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attack behaviors.

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So they may shoot faster or slower or they may even have different projectile types.

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The enemies are going to affect the player's score later on, so if they get destroyed, they're going

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to increase the player's score.

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And we may also add a mechanic in there to lower the player's score if they manage to escape unharmed

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and the enemies are going to spawn into our game in waves.

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Now, if you're not familiar with that term, let's have a look at what waves actually are.

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Well, you can kind of think of them as self-contained moments of gameplay.

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So we can see an example of a wave here where we've got two enemies following a set path.

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So for our game, a wave is going to spawn a certain number of enemies over a given amount of time,

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and all enemies in that wave are going to follow a set path once that wave has finished.

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So either all of the enemies have been destroyed or reached the end of the path.

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We can then go ahead and generate the next gameplay moment or the next wave.

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This could be the same as the first, or it could involve different enemies following a different path.

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So that's the basic mechanics of what we want to happen.

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But to get all this working, we're going to need a few different scripts working in unison.

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So next up, let's look at the scripts and their various responsibilities.

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First of all, we're going to need a wave config file and this is going to be a script object.

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This script will object is going to tell the wave which enemies need to be spawned.

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It's going to tell them the path that needs to be followed.

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And it's also going to control things like the time between enemies arriving within that wave.

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So they don't all just arrive at the same time and it's going to control the enemy movement.

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SPEED So we may have certain waves where the enemies are quicker or slower because all of this is contained

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within script or objects.

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We're going to need some scripts to actually use this data and the first is going to be the enemy spawn.

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This, unsurprisingly, is going to spawn the enemies into our game at the start of the path, but it's

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also going to dictate the order of the waves.

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So if we have multiple waves in our game, which we certainly will do, it's going to tell us which

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one to generate first and in which one to generate after that one has finished.

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And finally, it's going to be in control of the time between those waves.

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So that takes care of bringing the enemies into the world, but we also need to get them moving.

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This will be the job of an enemy.

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Pathfinding script and all this is going to do is tell the enemy to move to the next waypoint in a path.

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Now, we're obviously not going to get all of this done in one lecture, so let's just start by getting

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our enemy moving along a fixed path.

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And to create a path is actually incredibly simple because we're going to be using a waypoint system.

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So in our hierarchy, let's right click and create an empty game object and then reset the transform.

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And we'll call this object path zero because we very well may have more paths in the future.

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Then within this empty path object, let's right click again and create another empty object.

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And we're going to call this waypoint zero.

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And this time I've placed the zero in parentheses so that when we duplicate this object, it will automatically

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index these for us.

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Before we go ahead and do any duplication, though, the general idea is that we're going to have multiple

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waypoints in this path and then the enemy is going to move from one to the next.

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Because these are empty objects.

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We can't see them in our scene, which makes them very difficult to work with.

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So to fix this, rather than adding a sprite, which we would see in both our scene and our game view,

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what we're going to do is head up to the top of our inspector here where we've got this little cube

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icon.

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If we click on that, we then have some icons to choose from.

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I'm going to pick the yellow diamond so you can see what's going on here, and we can see that in our

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same view.

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We've now got this little yellow diamond.

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If we zoom in, we can see it a bit better.

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But if we look over on the game view, that little icon doesn't appear anywhere.

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So we don't like to have to worry about switching these things off in the game view.

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Now if we zoom back out so we can see our full game view again here in our scene, let's go ahead now

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and duplicate some of these waypoints.

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So just control the and I'm going to create five in total.

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All we have to do now is arrange them into a path that we want.

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I'm going to go with a similar path to what we saw in the slides, but feel free to create whatever

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kind of path you like.

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So with my path set up, I've got a nice sweeping curve here and notice that the start and end points

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are off of the screen.

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This is so the enemies can both appear and disappear off camera so that we don't get any abrupt changes

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where the enemy just pops in or out of existence.

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With our path set up, let's go ahead and prefab it.

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And rather than putting it into our prefabs folder because we're going to have a few of these, let's

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create a new folder specifically for our waves and our paths.

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So this will contain all of our paths and all of our wave config data later on.

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Let's go ahead and drag our path into that folder.

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And now let's look at how to get our enemy moving.

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We set the data for things like the path and the enemy movement.

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Speed would all be contained within a script object.

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So let's go ahead and go into our scripts folder and create this script object by right clicking, going

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to create and then C-sharp script and we're going to call this the wave config.

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So now we're not going to write this entire script or object in this lecture, but we are going to get

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enough information in there so that we can move our enemies.

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This is a script to objects.

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We don't need the start and update method, and we also need to change our mono behavior to be a script

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object so that we can create new wave configs in unity.

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Let's go ahead and add the Create Asset menu attribute to the top.

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I'm going to set the menu name to be wave config and I'm going to give it a default file name of new

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wave config.

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Now let's get our economy moving along the path this script will object is going to need two variables.

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These are all going to be serialized, filled, and the first is going to be of type transform and it's

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going to be the path prefab that we've just made.

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So this will contain all of the waypoints that we need.

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Next, we're going to have another serialized field of type float.

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And this is going to be the move speed for our enemy.

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And while we're here, let's give it a default value of around five.

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Now because these variables are private, being there in a script to object, we're also going to need

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some getters to access them from outside of this script and for the move speed, that's going to be

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fairly straightforward.

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We're just going to have a public float called Get Move Speed, and this is going to return the move

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speed.

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But for the waypoints in the path, things are going to get a little bit more complicated because we

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don't really need the container that those waypoints are in.

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We want the waypoints themselves.

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We're also going to want a quick way of grabbing the very first waypoint in the path as well.

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So let's start off with that one because it's a bit simpler.

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So our method for this is going to be public and is going to return a transform and we're going to call

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this get starting waypoint.

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And the starting waypoint in our path is going to be the very first child of this container so we can

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return the path prefab dot get child at index zero so that will return the very first child for us.

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Next, we want a way of returning a list of all of the waypoints.

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So let's create a public method.

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And this time we're going to return a list of transforms and we'll call this one, get waypoints for

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this.

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We're going to need to loop through all of the children within our path.

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Prefab parent object.

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And you may be thinking to yourself that a for loop is going to be ideal for this task and you're certainly

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not wrong.

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However, what we're going to do instead of using a for loop is we're going to use a for each loop instead,

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which works very similarly, but the syntax is slightly different.

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So how does a for each loop work?

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Well, first of all, let's remind ourselves of how a for loop works.

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And in the context of what we're doing, we may have a declaration, something like four int equals

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zero.

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So initializing our iterator at the first index of our path.

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And then while I is less than the child count of the parent prefab, we want to go ahead and grab the

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child and then increment our index by one.

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And as I said, there's absolutely nothing wrong with doing it this way.

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However, we could instead opt to use a for each loop which operates exactly the same but has a slightly

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cleaner syntax.

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So to do this exact same thing with a for each loop we could say for each child transform.

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So child is a variable in this case and it's of type transform in our parent.

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So in our case our path prefab, then we want to go ahead and do stuff.

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So let's head back over to our script and to return a list of all the waypoints in our path.

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Prefab First of all, we're going to have to create a new list of transforms and we'll call this waypoints.

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And then we'll initialize that to be a new list of transforms.

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Then we're going to go ahead and loop through all of the children of our path prefab.

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So using our for each syntax we're going to say for each transform child in path prefab.

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So we're going to take our path prefab and loop through all of the children and store them as transforms.

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And every time we do this, we're going to take our waypoints and add the child.

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Once we finished doing that, we've gone through all of the children.

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We can go ahead and return our list of waypoints.

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So let's save our script to object.

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And that should have everything we need for now.

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And to stop this lecture from getting too long, we're actually going to stop things there for now.

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And we're going to write the Pathfinding script in the next lecture.

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So well done.

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Forgetting our wave config script object started and I'll see you in the next lecture where we implement

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our enemy movement.

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So I'll see you there.