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‫Hello and welcome.

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‫In this lecture we're going to be working on AI Focus.

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‫So that is some built in functionality in Unreal that we can use to make sure that our AI characters

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‫follow us around the world are able to aim at us no matter where we go.

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‫Let's dive in and see how focus works.

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‫So I currently doesn't really do very much.

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‫And I think a first starting point for it to do anything would be for it to turn and face towards our

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‫player.

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‫Now to do this, we can use some built in functionality of the AI, which is setting a focal point.

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‫So if you have a look at the AI control and look for set focus, there's a couple of relevant methods

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‫here.

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‫One is set focal points, the other is set focus, and the one just below that is clear focus.

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‫So the idea here is that you can tell the AI controller that it should be trying to focus either on

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‫a particular point or it should be trying to focus on a particular actor.

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‫If you choose the latter, if you choose to focus on an actor, then what's going to happen is as that

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‫actor moves, you're going to keep focusing on that actor.

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‫Whereas if you chose to focus on a particular point, you would keep focusing on that point.

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‫But if that point was the location of an actor, when that actor moves, that point does not get updated.

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‫So typically focal points are for things that are fixed in the world, actors for things that move around

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‫that kind of makes sense.

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‫And then we have this clear focus function down here, which tells us that we should stop focusing on

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‫something.

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‫So that's how it works.

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‫You set a focus, you clear a focus.

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‫Now there is this priority variable in here which we are going to come to a little bit.

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‫But the idea here is that you've got different levels of priority.

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‫We've got this enum here which by default on set focus and set focal point is set to gameplay.

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‫If we go and have a look at the definition of that enum, you can see there is a default move and gameplay

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‫and they're basically listed in the order of priority.

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‫So gameplay will have the highest priority.

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‫If you set something as gameplay, that's what it's going to look at.

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‫If gameplay isn't set because you cleared the gameplay priority, then it's going to look where it's

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‫going and if it's not moving anywhere, then it's going to just look at the default priority, which

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‫might just be somewhere off in the distance.

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‫So if you've got a guard that's got a patrolling behavior, he'll default to looking to where he's next

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‫moving to once he gets there.

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‫You could set a default point for him to look at.

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‫So, I don't know, maybe he's looking at the entry way to his particular zone or something like that.

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‫Anyway, this is what the priorities are all about.

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‫As I say, we won't have to be using them too much because we're mostly going to be using this gameplay

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‫functionality to say that, Hey, there's something interesting going on over there.

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‫There's the player, so let's go ahead and look at him.

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‫So the first thing we're going to do is we're going to implement a begin play on our AI controller so

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‫that we can set the focus on Begin Play.

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‫This is just going to be to show us how this function works.

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‫So Begin Play, as we've probably seen before, it's a protected function.

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‫So we need to create a protected section and then we want our virtual void begin play.

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‫We're going to put the override keyword just for safety here and then we're going to go ahead and create

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‫the implementation over in the C++.

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‫And we're going to want to call to super begin play because that's always good practice because otherwise

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‫things in blueprints go wrong.

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‫If you forget to do this, if you ever have a problem with blueprints after you've created a begin play,

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‫make sure you check that you're calling to super.

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‫And then at this point, what we want to do is get hold of the pawn actor and set the focus to it.

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‫To get hold of a pawn actor, we can use a function from the gameplay statics header which if you hover

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‫over this or search in control p to find gameplay statics, you can find that this is under the kismet

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‫forward slash gameplay statics.

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‫So we'll go back over to the shooter I controller CP and include that.

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‫So hash include and then it's going to be kismet forward slash gameplay statics and then we should be

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‫able to do our U gameplay statics and use a function from within here which I find very useful is the

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‫get player pawn, which is going to return as a pointer to a player pawn.

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‫And it does that by taking in a world context object and the player index.

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‫In our case we're going to find the zero player.

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‫So let's get play a pawn and do a get world.

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‫And then we're going to look for index zero and we're going to save this into a variable, a pawn.

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‫At which is going to be the player -- like.

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‫So that's what we want to focus on.

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‫So it's challenge time for you to set the focus.

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‫Use the player -- that we've just got using our gameplay statics function call, set, focus and test

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‫it out in the world to see if you move around our different characters.

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‫Will they follow you?

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‫Will their gaze follow you?

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‫Pause video and find out.

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‫Okay.

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‫Welcome back.

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‫So hopefully it wasn't too difficult.

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‫We need to call set focus because set focus is on a parent.

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‫We don't have to find any pointers here.

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‫We do set focus and what have we got here?

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‫We just need to put in the actor basically because the priority is already got a default of being set

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‫to the gameplay, which is what we wanted anyway, so we can just pass in our player pawn and that should

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‫be who we focus on.

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‫So let's go ahead and build.

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‫And once that's done, let's hop over to Unreal and play.

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‫For some reason I still have this pesky spawn point here.

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‫Let's go ahead and delete that and make sure we're spawning near our eye character.

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‫Here we go.

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‫Let's go and have a look, a little walk around this character, and instantly I can see that he is

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‫turning to face my pawn wherever my pawn leads.

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‫So that is the beginnings of some AI in place.

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‫I know it's not much, but we're going to work on getting this even deeper in the next lecture.

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‫I'll see you there.