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‫Hello and welcome.

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‫In this lecture, we are going to be seeing things from the player's point of view.

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‫We will be getting hold of the players viewport, the location and rotation of the camera, essentially,

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‫so that when we hit the trigger button, we can draw a debug camera.

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‫These little red guys here, these little red boxy cameras that show us where that viewport is.

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‫And we can confirm that.

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‫We can then use that later on for raytracing for the gun.

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‫Let's dive in and see all of that in action.

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‫Let me start this lecture with a question.

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‫So if you are aiming through your viewport like this and you're trying to line up the center of your

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‫screen with that D on D command center or zero command center, whatever that's meant to be.

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‫And I aim what would I aim to?

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‫What would I expect to hit?

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‫You might say, well, I'd expect it to hit that zero.

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‫Sam, that seems like the obvious answer.

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‫Well, that's not necessarily what you are going to hit, depending on how you do things, how you do

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‫your recasting.

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‫So let's have a look at the strategies we have for recasting.

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‫The most obvious is you say, Well, we're firing out of the gun, so we're going to recast down the

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‫barrel of the gun.

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‫Or by the way, this set up, which is very, very crude, is basically our third person set up.

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‫We've got a camera back here.

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‫We've got the character, we've got the gun.

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‫And he's trying to shoot at another target character over here.

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‫So, well, first of all, we recast out of the gun like that pure.

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‫Maybe it misses because our camera is not pointing where the gun is pointing, not necessarily.

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‫Even though they might be pointing in the same direction, they're slightly offset from each other,

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‫so they won't necessarily hit the same things.

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‫Instead, you might choose that you want to recast from the camera.

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‫That means that whatever the camera is looking at is going to be the thing that is hit and that generally

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‫feels more natural in third person games.

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‫When you're in first person games, things get a little bit closer because often you're very close to

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‫the barrel.

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‫But even in first person games, this rule tends to be the case.

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‫You don't want to be moving around where the aiming point is on the screen.

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‫You typically have a little piece of UI that overlays here in the middle of your screen, and that's

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‫where you're going to aim down.

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‫And so that's why we tend to do our ray casting with ray casted weapons down this viewport.

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‫Now, fortunately, there's a way for us to get this viewport and we actually do it from the controller,

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‫we get the controller's viewport.

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‫So that requires us to go to the character, find the character's controller, and then find its viewport

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‫location and rotation.

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‫And what we're going to do in this lecture is try and visualize and confirm that that viewport location

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‫and rotation is what we would expect.

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‫And we're going to do that by drawing some debug helpers.

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‫Now the debug helpers are in a header file and the header files name is a debug.

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‫Helpers.

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‫Funnily enough, I believe or draw, draw debug helpers.

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‫That's the one.

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‫And if we go and have a look at this one F 12 to go navigate to a header file if you've already got

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‫it in your includes, we're going to look for a one called camera draw debug camera.

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‫And this draws something that looks a little bit like my diagram here, a little bit of a triangle or

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‫a nostrum that we can use.

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‫So what's it going to take in?

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‫It's going to take in the world a location of that camera, a rotation for said camera.

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‫So location, rotation, field of view.

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‫Well, we'll set that probably to a default like 90 degrees.

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‫There's a scale, there's a color defaults.

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‫These are all defaulted.

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‫So we can just use that defaults.

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‫So let's try draw a debug camera down here in my gun and we'll put it in the pull trigger method because

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‫that's why we're doing our work.

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‫It needs first of all, what was it?

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‫It was a new world.

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‫So we get our world.

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‫But we need to draw into the next thing would be a location.

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‫Let's just get actor location for the time being and do a get actor rotation as well.

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‫And then what was the final thing that we needed was a field of view.

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‫Let's just go for a 90 degree field of view, which is just a random thing there, and we can go ahead

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‫and compile and see whether this shows up.

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‫And then let's hit play and hit the.

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‫Trigger button.

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‫I'm not seeing anything here.

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‫Let's do an F eight and see if we can get closer.

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‫Still not showing any kind of camera in here.

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‫I'm wondering if it's really, really small.

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‫So one of the other options here is that we might want to have a persistent lines.

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‫And so that means we need to specify everything up to it in C++ so we can set our scale to one.

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‫We could even increase it maybe to a scale of two, just in case it's the size that's a problem.

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‫We can choose a color that's more visible, maybe red.

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‫So F color, colon, colon, red.

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‫And then we can try having persistent lines be true and try that one out for size.

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‫So compiling again.

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‫And jumping into play.

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‫And there we go.

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‫We hit.

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‫The trigger.

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‫And you can see that it shows up a little camera box here where we hit trigger and it's rotation and

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‫location are set by the guns and location and rotation.

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‫So now we want to try and get the viewport instead.

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‫So as I've already said, this is going to be on our controller.

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‫So let's look at Controller H and again, we want the one in the game framework and we're going to look

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‫for viewport in here.

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‫I beg your pardon?

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‫Actually, viewpoint is the word we're looking for and there's a few here.

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‫Get actor eyes a viewpoint that would be looking through the actor's eyes.

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‫But we actually want the get play of viewpoint, which for an eye controller will use their eyes, but

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‫for a player will use the player's camera.

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‫So that's what we want.

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‫We want the get player viewpoint.

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‫But first of all, we have to get hold of that controller in the first place.

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‫And the way to do that is, first of all, we need to get our owner remember that when we had our shooter

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‫character CP open and we go down to or go up to our Begin play, you can see we're setting the gun's

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‫owner to be the character.

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‫That means that in the gun we can go the other way.

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‫We can say get owner and that's going to get us the shooter character.

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‫Now it's not going to know that it's a shooter character.

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‫All it knows is that it is an actor.

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‫So we're going to have to do a cast here.

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‫So we'll do a cast to the A Shooter character.

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‫And in fact, we don't even need to know anything as much as the fact that it's a shooter character.

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‫It's sufficient to know that it is a pawn and any pawn can then possess this gun, even if it's not

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‫a shooter character.

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‫So try and be as nonspecific as possible.

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‫Why does it need to be a pawn, though?

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‫It needs to be a pawn because we need to get a controller and only pawns can be possessed by controllers.

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‫So let's put this in a variable.

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‫It's going to be a -- star and then owner -- is going to be the name of the variable.

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‫Then we need to check that this is not null.

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‫And I'm just going to do this with a one liner that says if it is null, we return early from our pool

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‫trigger so that we don't have any risk of trying to call anything with a null pointer.

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‫So then we can do a pawn owner, get controller and we want to save that in to the A controller.

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‫Star And this can be the owner.

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‫Controller.

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‫Like so.

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‫And again, we want to just check that this isn't null because we're going to be calling a method on

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‫that and we can't call methods on null pointers.

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‫It makes unreal, unhappy and crash.

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‫So this is where we can now do our owner controller.

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‫And we should be able to call to that get play a viewpoint.

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‫So here comes the challenge for you to set that location and rotation.

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‫Using that new function, you can see the signature for it.

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‫Again, we go to Controller H ahead of file and look at that get play a viewpoint.

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‫Try and see if from this signature you can work out how to use it to get that location and rotation

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‫that we want to pass in to our draw debug helper.

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‫And so you're going to remember that this is using out parameters.

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‫So revise your out parameters, draw the debug camera using that snippet that we've just written and

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‫test it in the viewport.

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‫Go and click the trigger button a few times in different locations and see where that camera ends up

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‫showing pause video and have a go.

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‫Okay.

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‫Welcome back.

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‫So get play a viewpoint.

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‫I'm going to copy the name of the method and bring it over here because it's an out parameter.

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‫I will need to declare first the variables that I want those values to go into.

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‫I've got an F vector location.

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‫We have got an F rotator rotation.

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‫And we want to pass those in as the arguments.

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‫Let me just fix up my indentation there a little bit.

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‫And we're going to pass in the location, the rotation.

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‫And we know that because it's just been declared here when reading this, we can guess that these are

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‫now out parameters, even though there isn't any syntax helpfulness from C++ on that regard.

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‫And then we can pass this location instead of the actor location, and we can pass this rotation instead

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‫of the active rotation into our draw debug camera.

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‫And we can go ahead and build that compile and try it out in the editor.

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‫Well, it looks like the compile is complete.

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‫Let's go and play.

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‫And when I hit Trigger, you could see a camera appearing right over my viewpoint.

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‫That's a good sign.

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‫If I step back a little bit, you can see there you go.

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‫We've got these cameras that are pointing in exactly the right direction from where I was just looking.

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‫So you can just imagine how we're going to be able to shoot a ray out of that camera down the end of

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‫the camera and try and hit something over there that I was looking at at the time.

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‫And that's what we're going to be doing in the next lecture.

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‫See you there.