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‫Hello and welcome.

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‫In this lecture we're going to be making rotating as well as moving platforms.

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‫We're going to do this by learning about the F rotator type in C++ so that we can add a little bit more

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‫of a another element to our puzzle.

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‫Let's dive in and find out how this works.

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‫So let's talk about filling out our rotate platform function.

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‫So in order to do rotation, it's very similar to the way we do location and we've got very similar

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‫functions.

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‫We can call instead of calling, get actor location, we can call, get actor rotation instead.

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‫And if I go and put parentheses on the end of this line and just hover over the function, then Visual

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‫Studio IntelliSense is going to show us that the return value from this is an F rotator.

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‫We've used the F vector when working with locations and we've talked about rotators in the previous

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‫sections.

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‫So let's have a look at putting this F rotator into a local variable.

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‫So the type is going to be F rotator and we're going to call this the current rotation equal to the

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‫get actor rotation, put a semicolon at the end of the line.

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‫I'm also going to delete the log statement because we no longer need that.

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‫And then what we want to do is essentially exactly the same as we've done with the platform velocity,

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‫which is a kind of rotational velocity multiplied by the delta time added to the current rotation.

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‫So what should that rotational velocity be?

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‫Well, that's where we want to go over to the header file and add a new U property.

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‫So I'm going to add it underneath the move distance and I'm going to have a U property edit anywhere

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‫and then give it a category equal to this time I'm going to call it rotation and I'm going to change

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‫the category name from moving platform to moving in both instances.

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‫So we're going to have a category for moving, a category for rotation.

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‫Then underneath the property we're going to put an F rotator called rotation velocity and we're not

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‫going to give it a default value here because by default I don't want any of our platforms to rotate.

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‫So the default value is going to be 000, and that's just what we need.

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‫So I'm going to put a semicolon on the end of the line here and now we can go back over to the C++ file

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‫and use that member variable in our rotate platform function.

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‫So what we want to do is current rotation equal to the current rotation plus rotation velocity multiplied

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‫by Delta time and put a semicolon on the end of the line.

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‫And now the final piece of the puzzle is to set our actor to that new rotation.

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‫So exactly as you would expect, maybe a little mini challenge for you, in fact, is how would you

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‫go ahead and do that yourself?

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‫Well, what we would use is the set actor rotation function and we would pass in an argument of current

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‫rotation like so and put a semicolon on the end of the line.

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‫Now, unfortunately, it doesn't work quite as simply as this.

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‫It's come to my attention, some students have pointed out in the teaching assistant.

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‫Dan, thank you very much, has pointed out that just adding rotations together like this won't always

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‫work because of some of the complications around rotations wrapping around themselves.

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‫If you go all the way to -90 degrees of rotation, at some point you need to flip over into plus 90

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‫degrees of rotation and so on and so forth.

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‫So a better way around this, instead of setting the active rotation, is to call the add actor local

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‫rotation.

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‫And you can notice here that there are a few add actor local trans form as well and local offset that's

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‫for location.

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‫So you can use that as well instead of adding location.

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‫However, there aren't the same sort of problems that we're going to encounter in the edge cases around

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‫rotation.

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‫So what I would recommend you do is add actor local rotation here instead and then you just put in the

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‫rotation velocity multiplied by the Delta time and it does the rest of this code automatically for you.

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‫So we can just go ahead and get rid of those lines.

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‫And you've got a straightforward addition to the local rotation going on here, and you can also get

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‫rid of this getting the current rotation because we no longer need that either.

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‫So let's head over into the editor and hit the compile button.

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‫And when that's done, close the log.

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‫Let's select one of the platforms in the level any of them will do and have a look at the categories.

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‫So we've got moving and we've got rotation and we've got the rotation velocity then.

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‫So I want to rotate this platform around its Z axis at probably let's say about 90 degrees per second.

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‫So it takes 4 seconds to do a full rotation.

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‫Let's go ahead and hit play.

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‫And there you go.

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‫We've got a rotating and moving platform.

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‫So unlike the mechanism of the moving platform, we don't have to worry about our rotating platform

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‫actually going backwards and forwards.

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‫If you want it to do that, that's a possible extension you could think of.

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‫But for me that is enough because we just wanting these things to keep going round and round in the

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‫same direction.

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‫So let me go and remove the rotation from this particular platform because we don't want this platform

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‫to be rotating.

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‫So I like to challenge you to make a beep rotating platform, basically yet another variant for us to

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‫use and find an appropriate mesh.

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‫I would go with something that's vaguely circular so that it makes sense as a rotating platform and

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‫give it a default rotation speed and place it in the level to create a bit of a rotating platform puzzle

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‫for you to get across.

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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 we're going to go ahead into our content drawer and going to look for the C++ classes, Obstacle

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‫Assault and right click the moving platform to create a blueprint class device derived from this.

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‫We're going to call it the BP underscore rotating platform and we're going to put it in the route of

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‫content and create blueprint class.

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‫Once the editor pops up, let's dock it to our main window.

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‫I'm going to close my content browser that seems to want to pop up every time, and I'm going to go

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‫to our main level and go to the island with all our test assets on right click.

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‫Go here and let's see if there's anything that looks good.

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‫I like the look of these platforms here.

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‫If I right click on it or if I just click on it, then the mesh being used here in the static mesh is

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‫SM platform A So let's look for that one.

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‫Let's go over to our blueprints, open up the content, draw, go to all and then search for platform

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‫underscore M, underscore A and then we've got the mesh, which is this one here.

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‫Second one along for me.

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‫I'm going to drag it in to our viewport to have our platform.

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‫Now let's see where this is centered.

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‫Is it centered on the middle?

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‫Yes, it is, which is good and important because we do need it to rotate around the middle.

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‫Otherwise this circular platform is going to look a little bit strange.

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‫We can also scale it up a little bit in the x and Y dimensions to make this platform a bit larger and

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‫we can go to the class defaults to remove any platform velocity because we don't want it to move and

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‫set the move distance down to zero potentially and then look at the rotation section and set that to

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‫about well, we tried 90 degrees per second and that seemed fairly reasonable.

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‫So let's go ahead and save this rotating platform.

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‫We'll go to our main level and then right click on the little floating island where we've got our level

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‫set up our puzzle, click, go here.

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‫Then on top of this island, I want to place down our new blueprint.

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‫So let's cancel out the search, go to root of content and find our rotating platform and place it in

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‫the level.

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‫And instantly I'm seeing I actually want it to be a little bit bigger.

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‫So let's go ahead and scale it up.

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‫A few more units, maybe three times should be good.

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‫Let's go and have a look.

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‫Now, I think it could be even larger still, so I'm going to scale up a bit more so that essentially

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‫in the X and Y it's five times larger than it was originally.

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‫Okay, that's a nice wide rotating disk and might be quite challenging for us to get across.

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‫So I'm going to duplicate these using alt and drag to make a few of them across the platform and try

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‫and place them appropriately and then alt drag a few more.

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‫So that we've got a nice little set of puzzles here for us to try and get across.

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‫So just wiggled them around a bit until I could get them pretty much edge to edge.

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‫And here's where being able to have a game mode really helps because we can right click near the platforms

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‫and the click play from here, and here are all of our rotating platforms for us to step upon.

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‫And it's a little bit of a challenge now for us to find our way across these moving platforms nice and

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‫easy.

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‫Now there's this dead zone in the middle which we could try and blank out, but it's actually quite

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‫hard to get and stay in the dead zone, so I'm not going to try and put anything in there specifically

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‫to try and stop that.

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‫But you can see there you go.

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‫It's a doable challenge we can get across, but it's a little bit tricky and that is fun.

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‫Great stuff.

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‫So in this lecture, we've seen how to make rotating platforms by learning about a new type, the F

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‫rotator and how we can use it to set the rotation of our actors.

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‫I'll see you in the next lecture.