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‫Hello and welcome.

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‫In this lecture, we're going to be looking at how we can create new nodes in Blueprint from our C++

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‫so that essentially we can be calling C++ functionality from within Blueprint.

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‫Let's dive in and see how it's done.

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‫Now, it's all well that I can use blueprints to call to blueprint nodes, but I actually want to activate

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‫our grabber from this piece of blueprint here, not print out some strings.

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‫So how do I go about doing that?

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‫Well, fortunately, we can quite easily expose a function from a C++ class in to blueprint.

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‫And the way we do this is as follows.

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‫So we're going to go and create a new public function.

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‫So I'm going to go to my public section just under the tick component.

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‫And here I'm going to create a new function with a void return type called release.

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‫So we're going to do grab later on, but we're just going to call a release function for now.

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‫How do I make this available in Blueprint?

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‫Well, I need to make it a U function.

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‫So you've got you properties for variables.

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‫You function is kind of the equivalent for making a function basically visible in the land of blueprint.

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‫But we don't stop there, just like with the new property.

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‫We have to make it edit anywhere here with the u function we have to make it blueprint callable and

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‫that, as the name suggests, means that this function now becomes a node that blueprint has access

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‫to.

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‫So let's go over to the grab a CP and create an implementation for this.

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‫It's going to be void return type.

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‫It's going to be a U.

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‫Grabber, colon, colon release, no parameters.

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‫And we'll put a function body, which I'm going to stick a u log in and I'm going to give the message,

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‫be released grabber like so and then we can compile and back in our beep.

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‫Player I'm going to delete the print string node and I'm going to drag off of released here and I'm

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‫going to search for release as a function in here.

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‫Now let's go and have a little bit of a look around.

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‫Nothing's showing up at the moment because I need to do this on the grabber.

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‫So let's take the grabber component, drag it into the event graph to create a grabber variable, then

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‫drag off of this and search for release.

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‫Now, you notice nothing's coming up in this case either.

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‫And that's because we've used live coding and sometimes things that are compiled in live coding do not

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‫show up in the editor.

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‫What we have to do is close down the editor, close down the live coding window and then in Visual Studio

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‫code, hit control shift B and build using the Crypt Raider editor win 64 Development Build.

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‫Wait for that to succeed and then relaunch the editor from the new project file.

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‫Now if we reopen our BP player and now dragging off the grabber, we search for release.

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‫You can see that now there is a node called release.

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‫And indeed all that's going to do is going to call as C++.

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‫So you can see how you can really use Blueprint and C++ in close collaboration this way by exposing

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‫C++ things into the Blueprint world.

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‫Now I'm going to connect up my release execution pin to the release node.

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‫We're going to go in to our dungeon and we're going to hit play.

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‫And now if I were to grab and then release, you can't see anything because it's in the output log.

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‫So let's open up the output log and dock it to the layout, then hit play again.

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‫And now when we grab and then we release, you can see there is a brief message there.

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‫It scrolls by really quickly because every tick we are doing this hit gargoyle status statue thing.

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‫But there if you stop and look back through the log, you can see it said released grabber.

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‫So our C++ code is being executed.

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‫Okay, so now I'd like you to move our sweep code in to a grab function.

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‫So you're going to create a grab function and call it from Blueprint.

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‫You're going to do it the same way as I just did the release function.

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‫But when you create the body of the grab function instead of just printing anything, let's move that

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‫sweeping code and the if statement and all the prep variables from TIC so that it's not doing it.

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‫Every single time we tick to just when we call that grab function, when we press our mouse button down

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‫or press a trigger on our controller, so then recompile and check the logs to make sure that indeed

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‫that's only happening when you press the button, pause the video and have a go.

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‫Welcome back.

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‫So let's go in to our C++ and up to our header file.

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‫I'm going to close down the compile window here and above release.

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‫I'm going to create a new U function blueprint, callable, which is going to be void called grab and

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‫we're going to implement this over in the C++.

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‫So again, it's going to be a void.

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‫You grab a colon, colon grab parentheses and then braces.

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‫And I'm going to move all of this code from TIC component because we are setting up our start vectors

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‫and all that sort of good stuff.

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‫Let's go all the way down and cut it out and paste it into grab instead where it should be.

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‫Just fine.

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‫Now let's see if live coding will bring about the function in the BP player.

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‫Let's go over to the beep player, delete our print string and let's drag off that.

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‫Grab a node we've got and see if we can find a grab function.

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‫Okay, so this time the grab function was available to us.

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‫That's great.

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‫Now let's hook up the pressed execution pin, go over to our dungeon, hit play and make sure we scroll

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‫down to the bottom of the output log.

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‫Going to right click into my viewport and have a look around and then I'm going to press my left button.

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‫It says No actor hit and then instantly the release grabber, so no actor hit.

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‫And then I release the key, no release grabber.

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‫Now if I go up to my gargoyle, I'll have a look at it.

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‫I press on it and it says Actor hit Gargoyle Statue and then I can release the grabber.

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‫So now we've got the right sort of architecture in place in order to grab this gargoyle.

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‫Next, we need to deal with the physics part of this setup.

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‫I'll see you in the next lecture.