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‫Hello and welcome.

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‫In this lecture, we're going to be creating actors and objects in our scene while we are playing.

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‫So if I hit spacebar, it adds in a ball and it adds the impulse to the new projectile that we have

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‫created, allowing us to create much more dynamic scenes and games.

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‫Let's dive in and see how this is done.

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‫So ideally, these projectiles would not be in the scene when we start, because that's not how projectiles

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‫work.

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‫You tend to create them when you want to shoot in a game and that is called spawning in the same way

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‫as you might spawn an NPC in any game that you play.

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‫Well, we can spawn actors into our level as we're playing as well.

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‫So let's go ahead and delete all but one of the projectiles in our scene and we'll see why in a second.

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‫We'll use one of them as a reference to figure out where we want our projectiles to spawn.

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‫But we do want to go ahead and go over to our level blueprint.

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‫And over here, what we want to do is disconnect the space bar event from the add impulse just for now.

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‫The way you can do this is by clicking either on the execution pin coming out of the space bar event

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‫or on the one coming in to add impulse.

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‫And that just goes ahead and removes the wire between the two.

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‫And now what we want to do is dragging off our press event.

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‫I want to search for a spawn actor node.

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‫There's a node called Spawn Actor from class and that's the one we want.

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‫You can see that having dragged off the execution pin, it automatically connects it up to the input

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‫pin of this spawn actor node.

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‫Now there's a couple of properties we want to configure to tell the node how to do its job.

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‫First of all, we need to tell it what it should be creating which class, which blueprint class should

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‫it be creating an instance of?

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‫Well, we got a handy little dropdown here and it's got a search box so we can search for projectile.

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‫And BP projectile is the only one that shows up.

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‫So we can select that.

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‫So we can see that the spawning is essentially just creating an object while we're playing.

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‫Now, what about this node here?

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‫The next one down is Spawn.

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‫Transform.

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‫What's a transform?

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‫Well, a transform is just the combination of the location, rotation and scale of an object.

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‫We use these three things together so much in games that it's just given a name which is transform.

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‫And what we can do is if we go over to our minimal default level and see the viewport, we can move

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‫our BP projectile around.

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‫And looking in the details pane, you can see that there's a section called Transform and indeed the

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‫properties underneath it are called location, rotation and scale.

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‫And you can see the X, Y and Z values for each.

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‫So we've got this projectile and quite usefully it's got 60 X and 120 Z.

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‫I'm just going to make a note of that because if we go back to the blueprint and right click on the

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‫Transform Node, we can click the split struct pin.

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‫Now, don't worry about what that means exactly just yet.

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‫We'll cover that in a later lecture.

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‫But what we've got now is is split out the transform into its component parts such as the location,

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‫rotation and scale.

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‫So that just allows us to put the newly created projectile in a certain location.

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‫So X is going to be 60, Y was zero and said was 120 and that's going to give us the correct location.

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‫And we don't need to worry about the rotation and scale the defaults.

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‫There should be just fine.

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‫So if we go ahead and hit play and then if I hit spacebar, you can see it creates a second projectile

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‫in exactly the location that the first projectile was and go ahead and create as many of these as I

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‫like just by keeping on hitting spacebar.

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‫Now the final thing to note is that there is a return value pin as the output to Aspen actor.

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‫Now we've used this term return quite a few times.

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‫Return pin or return value.

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‫It's just the output of a node.

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‫It's data or objects that come out as a result of executing that node.

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‫So this return value, what is it?

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‫Let's hover over it and you can see it says the beep projectile object, reference, return value.

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‫And underneath it it says it's the constructed object.

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‫So it's the object that we have spawned, essentially the new projectile.

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‫And so we can now get rid of the reference to the cube in our blueprint because we no longer want to

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‫be adding an impulse to the cube.

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‫We actually want to be adding it to the projectile that we've created instead.

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‫So that's going to be your challenge to hook up the impulse.

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‫I'd like you to hook up.

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‫First of all, the execution pins, the correct order should be the add impulse should happen after

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‫the spawning.

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‫We need to.

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‫Hook up the data pin as well so that we are getting the static mesh from the newly created projectile.

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‫And where should we be adding the impulse to?

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‫What is it that we're adding it to from that new projectile?

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‫Pause the video and have a go.

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‫Okay.

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‫Welcome back.

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‫So you may have guessed that what we're trying to get the static mesh from is the projectile, as I

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‫said, but that then it's that static mesh that we're trying to add the impulse to.

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‫So we're creating a new projectile, we're getting its static mesh component, and then we're adding

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‫an impulse to it.

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‫And now we need to just hook up the execution pins to make sure that ad impulse is indeed run after

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‫we spawn the actor.

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‫So let's see what that looks like.

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‫If we hit play and we hit the space bar, you can see that the newly created projectile that spawns

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‫into the level gets a little impulse added to it, and we can increase the value of that impulse if

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‫we wanted to, to make it jump a little bit higher into the air, which is just a little bit more fun,

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‫isn't it, when things jump up nice and high and that's it.

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‫Basically, we've created the basics of spawning in a projectile, so I will see you in the next lecture.