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‫Hello and welcome.

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‫In this lecture, we're going to be taking our mess of blueprints and organizing it neatly into functions

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‫so that we can easily read and understand what's going on in our Blueprint Event graph.

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‫Let's dive in and see how to do this.

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‫Now, if we zoom out on our event graph, we can see that it's starting to get very noisy.

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‫I can also see a couple of nodes that aren't connected up to anything.

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‫There's a get node which I'm going to delete, an asset, M0 node, but you can see it's getting very

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‫noisy.

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‫It's getting hard to understand what's going on here.

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‫Now, a typical solution that people do is to say, Well, this block of nodes here is all about spawning

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‫the projectile.

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‫So I can select these.

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‫I can hit the C key and it is going to put a block around this called a comment block.

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‫And then I could type in spawn projectiles and that lets me know what that block of code is doing.

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‫That is certainly one way to organize your code.

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‫However, in my opinion, it's not the best way and we have got better tools for doing this called functions.

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‫So what are functions?

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‫Functions execute blocks of blueprint and make our games do things.

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‫Many nodes that are provided by Unreal Real are actually functions already.

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‫So we've encountered these.

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‫When you go and zoom in say on our spawn actor projectile node, that is a function.

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‫When we look at add impulse, that's a function to in fact most every one of these nodes, even things

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‫like get forward active vector that doesn't have an execution pin and isn't blue is also a function

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‫you can tell because it has a little f symbol in the top left that stands for function, but we aren't

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‫restricted to the functions Unreal provides.

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‫We can create our own functions too, and it's really easy to do.

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‫In Blueprint.

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‫They allow us to stay organized and they allow us to reuse blocks of code.

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‫So that's better than a comment because a comment you have to copy and paste.

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‫Whereas a function allows us to share one block of code between multiple places of use.

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‫So let's take a look at how we can turn something like this in to a block of code.

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‫Well, we can delete the comment block, first of all, because I don't think that's necessary.

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‫Instead, I'm going to select all of the nodes from get player -- all the way to add impulse, right

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‫click on them and select collapse to function.

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‫And that creates a new block and replaces all of those previous nodes that were there before.

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‫Now I'm going to give this function a name you can see over in the left hand pane.

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‫It's created a new function under the function section in the my blueprint pane and it's got it selected

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‫for me to automatically rename because we should definitely, definitely rename these functions and

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‫I'm going to call it spawn projectile.

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‫And good naming is absolutely vital in program because code is essentially all about communication.

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‫We're trying to communicate with ourselves so that we can understand what we've written.

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‫We're trying to communicate with ourselves in the future.

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‫When we come back to this project, have forgotten why we've written it a certain way.

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‫And when you work in teams, you're trying to communicate with the rest of your team too.

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‫Some say that a good metric for code quality is the what the heck's per minute.

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‫So if you're reading a piece of code and you're going, What the heck, 50 times a minute, that's pretty

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‫bad code if you're reading it and only going, What the heck, once or twice a minute, then that's

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‫probably pretty good code and you're always going to get somewhat the hex.

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‫So we're just trying to reduce that number their functions.

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‫Crucially, we tend to name functions as verbs.

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‫There are some exceptions to this rule that we'll talk about later on, but mostly functions are things

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‫that are doing something.

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‫So we use doing words and if you're unsure about how to name this function, then if you're working

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‫in a team, you could just talk to somebody else and ask them what they think you should name it and

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‫what kind of things make sense to them.

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‫You often find that you're so ingrained into a problem that you can't think of how to talk about it.

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‫So you may be asking yourself, Well, where did all my code go when I created this spawn projectile

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‫function?

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‫Well, you can get back to that detail of how this function is actually implemented by either double

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‫clicking it in the event graph or clicking on it in the My Blueprints tab or double clicking it on the

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‫My Blueprints tab.

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‫And you can see that we've got all of our nodes still resident here just now they're in a separate tab

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‫so you can go back to your event graph tab or you can dive in to the Spawn projectile tab which shows

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‫just that one function.

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‫And you can see there's a new node here, this little purple node, which is the entry point to our

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‫function.

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‫This says this is what we should do when the function starts.

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‫It's just an entry point.

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‫And whenever it's called, that node is going to trigger and trigger all the rest of the nodes inside

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‫of our function.

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‫So going back to the event graph and.

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‫Zooming out, maybe bringing our nodes together a bit.

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‫Now that we've made our node graph so much smaller and easier to read.

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‫I think there are a couple more candidates here for us to pull out functions and replace things.

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‫One of them would be where we are printing out ammo.

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‫So in this case, printing ammo is something that we do in two places.

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‫We do it in begin play and we do it down in spawn projectile.

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‫And then the other place, the other thing, piece of functionality that we could extract into a function

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‫would be where we are decreasing the ammo that could be put into a decrease ammo function instead.

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‫So just before I set you the challenge, I would like to delete the conversion node and print string

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‫node at the after the spawn projectile because this is going to complicate matters.

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‫I would like to copy the functionality from up above so that they both look exactly the same.

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‫So if we copy the three nodes from Begin Play and paste them down below and connect up the execution

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‫pins, then you can see we've got exactly the same set of nodes here, the same functionality between

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‫the two, and there's no confusion when we come to extract this into a function.

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‫So I'd like to challenge you to make some more functions.

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‫The first one I would recommend doing is the decrease ammo.

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‫So taking the three nodes involved in decreasing ammo, extracting those into a function and giving

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‫them a name.

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‫And then the second one is print ammo.

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‫So there you're going to be extracting out the functionality of getting, converting and printing the

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‫ammo into a single function.

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‫And because we've got two sites where we're printing ammo, you might want to delete one of them and

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‫bring in the function instead, which you can do by dragging from the my blueprint pane.

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‫And then finally we've got a couple of welcome messages, output of welcome message nodes.

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‫You can extract those into a print.

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‫Welcome messages function as well.

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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 extract our decrease ammo first.

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‫So there's three nodes involved in that.

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‫We'll right click collapse the function, then we're going to call it Decrease Ammo and that's fairly

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‫straightforward.

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‫So spawn projectile, decrease ammo and then we are printing the ammo.

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‫So let's take the three nodes, the get convert and print string and we're going to right click collapse

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‫to function and call this one print ammo.

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‫Now as I said, we've got this functionality repeated in two places, so we'll delete where it does

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‫this in begin play and just drag in print ammo from our functions list and connect up the execution

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‫pins so that it runs after our print string.

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‫Which brings me on to the last function I want to create, which we said we'd call print welcome messages.

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‫So I'm going to select the to print strings after being in play collapse to function and call it print

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‫welcome messages.

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‫And this node, we can just now rearrange all of our nodes to make it far easier to read all of this

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‫in one screen full.

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‫You can see it's much easier to understand the functionality of our game now because it's all fits on

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‫one screen and is nicely brought to a similar level of abstraction and understanding.

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‫And this is what we would call self documenting code, because it is code that doesn't need comments

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‫or documentation to explain what it does.

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‫It just reads like English.

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‫Great stuff.

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‫I'll see you in the next lecture.