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In the last lecture, we turned our audio player into a singleton so that when we changed our scene,

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the music would continue to play.

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And during that lecture, I also asked you to think about some other objects that may benefit from being

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a singleton.

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So hopefully you had a good think about that question.

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And there were a couple of different answers depending on the approach you're taking.

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One valid option is that nothing should be a singleton and there are better or different ways of approaching

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our code to make sure we don't use them.

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But assuming we do want add some singletons to make our life a little bit easier, the first candidate

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would be our level manager because we've got one of these in every single scene.

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They're all doing exactly the same thing and we only ever really want one of them at any given time.

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But since having multiple level managers in a scene is not really going to break anything, it's not

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essential that only one ever exists at a time.

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The only real benefit I can see from making this a singleton is if we make it a pure singleton and have

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global accessibility.

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So we only ever have one in our entire game because we can then stop worrying about this scene.

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Loaded delay in our hierarchy.

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Because if we change this in our main menu, it's not going to translate over into our game scene at

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the moment.

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So we could potentially change things in the wrong place and it will become a bit of a nightmare.

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But for now, the way I said we can get around this is just to remember or add a tooltip maybe to our

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script to tell us not to edit this in our same view and instead only change it on the prefab version.

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So as long as we haven't overridden it somewhere, it should update everywhere.

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Turning our level manager into a singleton would also create some other problems that we would need

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to solve, like how our canvas buttons are currently linked up to our level manager.

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So if we start moving that between scenes, we're going to have to have a script attached to our canvases

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to allow our buttons to find the level manager that's in the scene at a given time and then hook themselves

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up.

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So it's going to create more work than we really want to do.

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So let's leave our level manager alone because it is working perfectly fine as is.

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But the other candidate for a singleton, which I think we will pursue, is going to be our scorekeeper

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because we currently have a scorekeeper in our game scene for tracking our actual score during play

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and our game overseeing for displaying the score at the end.

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Our scorekeeper needs a way of transferring that score from one scene to another, so it would make

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sense if the same object got carried across.

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And we also want to make sure we don't end up with more than one scorekeeper in a scene.

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If we ended up with two or three scorekeepers in our game scene, then every time we scored points,

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we'd be scoring triple the points.

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So our scorekeeper is going to make a good single turn, I think.

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But before we go ahead and set up our script, let's just do a little bit of extra work on our canvas

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so that we can find our score, text and update it.

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So over on our canvas we're going to add a new script.

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So over in our script folder, let's right click create a new C-sharp script, and I think we'll call

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this one the UI game over.

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Let's track that onto the canvas and then open it up.

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And if you fancy a bit of a mini challenge, then go ahead and write this script completely on your

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own and I'll give you a moment to pause the video if you want to do that.

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Okay.

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So if you did this as a mini challenge, very well done.

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Or if you want to follow along, that's absolutely fine as well.

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So let's first of all get rid of our update method because we're not going to need it.

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We will need to start.

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But let's clear off our comment and we're going to want to connect this script up to the text mesh pro

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element on the canvas.

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So the top of the script, we're going to include a new using statement and we're going to be using

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TM Pro.

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Then let's create a serialized field for our text mesh, pro-EU Gooey Element and call this the score

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text.

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Let's also grab a reference to our scorekeeper and call this the scorekeeper.

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And then in a wake, let's set our scorekeeper to find objective type scorekeeper.

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Finally, let's set our score text in start so we can say score text.

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Text is equal to our scorekeeper.

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Don't get score.

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Now this is returning an integer, so we're going to need to turn it into text.

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We can do that like we did in our game scene by just adding the two string method.

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But if you remember back over on our canvas, we also have this.

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You scored part of the scoring message.

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So we can actually do away with this two string method if we want, because when we start concatenating

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strings and integers, the whole thing will get treated as a string.

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So let's add our little message of you scored.

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And to place our score on a new line, we can just use the new line character.

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So let's save this up and jump back over into unity over on our canvas.

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Let's take our UI, game over script and drag over the score text.

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And if we hit play now, we should have a message of you scored zero.

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So that seems to be working.

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And the next step is going to be to convert our scorekeeper into a singleton.

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And this is going to be your challenge.

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I want you to turn our scorekeeper into a singleton.

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So if you feel up to taking on that challenge without any further advice, then go ahead and pause the

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video now.

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But if you want a hint, then take a look at what we did in our audio player for reference, because

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this is going to come in very handy for you.

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So pause the video now and give that a go.

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Okay.

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Welcome back.

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So to set this up as a singleton, let's take a look at what we did for our audio player.

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We had a static audio player instance and then in a wake we were calling our managed singleton method.

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This method was checking whether our instance was null.

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So if we weren't the first object to come along, then we were going to get destroyed.

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Otherwise, if we were the first ones to come along, then we're going to set the instance to this version

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of our audio player.

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So let's actually copy all of this.

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So our static variable, our awake method and our manage singleton method, and then over in our scorekeeper,

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let's just copy and paste that into our code and pretty much all of it can stay as it is.

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The only thing we're getting an error on is when we try and set our instance to this, because we're

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trying to set a scorekeeper into an audio player, which definitely isn't going to work.

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So instead for our scorekeeper we need a static scorekeeper instance.

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This will then get rid of our red error and everything should work as expected.

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So let's save up our script and jump back into unity.

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And if we go ahead and hit play, we should find that our score initially gets set to zero, which it

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does.

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And when we play again, our score is zero.

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But if we rack up some score before we die, so let's just get a couple of points.

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100 is fine before we die.

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This hundred now gets carried over to our score.

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But we've now got a secondary problem that if we play again, we start off with a score of 100.

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So our next step is to work out when and where we want to call our reset score method.

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Well, if we head over to our script and open up our level manager, it would be a good idea to reset

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our score whenever we load our main gain.

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So this script is going to require a scorekeeper called scorekeeper.

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And then in awake we need to find this scorekeeper.

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So avoid awake scorekeeper equals find objective type scorekeeper.

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And I'm sure all of this finding stuff in awake over and over again is really starting to tempt you

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into that public and globally accessible singleton pattern that we looked at last time.

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But with that set up, then let's go into our load game and before we load the scene we want to say

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scorekeeper dot reset score.

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So whenever we load into our main game, our score will now be reset.

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So let's save all of our scripts and jump back into Unity one last time for some testing.

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Let's go ahead and hit play and we're on the game over screen at the moment.

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So our score is zero.

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But if we play again and rack up some points, we don't need to rack up many.

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We really just need the minimum amount of 50.

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Our score is transferred over, but if we play again, our score gets reset.

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And we thought, I think our game is pretty much there.

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We have a nice gameplay loop which we created with our different menus.

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Our score is nicely transitioning across from our different scenes and being reset at the right time.

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Our audio player is playing our music consistently through our levels, and really the only thing left

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to do is to add some more content.

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So more waves, more enemies, more explosions, playtest our game and finally build our game so that

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other people can play it.

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So congratulations on getting everything working and we'll talk about some play testing and balancing

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in the next lecture.

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So I'll see you there.