You will learn to make fluid digital interactive experiences that are suitable for gaming and use the advanced sensor hardware built into the iPhone and iPad. This includes drawing 2D graphics, playing sounds and music, integrating with Game Center, the iOS physics engine and detecting device orientation and location. Upon completing this course, you will be able to: 1. Use the reverse geocode service to convert latitude and longitude to location names 2. Implement GeoFences to make an app efficiently monitor an iOS device’s location 3. Leverage the power of accelerometers, magnetometers and gyroscopes to orient a device in physical space 4. Create an app that responds to ambient light levels by using screen brightness as a proxy 5. Play sound effects and other media as audio 6. Make a game like Pong 7. Make a game like Breakout 8. Manipulate graphics in a game environment 9. Use the physics engine to create realistic game worlds 10. React to multi-touch events for complex interaction design 11. Detect and respond to collisions and contacts efficiently 12. Chain complex sequences of actions, animations and sounds with precision 13. Animate multi-frame sprites 14. Create particle systems to simulate fire, smoke and magic (and more!) 15. Interface with Game Center to create leaderboards and achievements that can be shared through social networks
Intro to Game Center
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Do curso por University of California, Irvine
Games, Sensors and Media
51 classificação
University of California, Irvine
51 classificação
Curso 4 de 6 em Specialization Desenvolvimento móvel em iOS para Empreendedores Criativos
Na lição
Where the Action Is
In this final week we will explore the different actions that can be initiated by your Sprites to create dynamic games. By leveraging the SKAction class, complicated multi-step animations, sounds and effects can be chained together without the app developer having to micro-manage their unfolding. We will also introduce particle systems as they are a fun and efficient way to simulate effects like smoke, fire and magic. Lastly, we will show you how to interact with Game Center so that you can add social action to your games. That includes leaderboards and achievements that are visible to the user’s social network and add a fun element of competition to any game.
Conheça os instrutores
Don PattersonAssociate Professor
Informatics and Computer Science
Sam KaufmanPartner at Gradient
[MUSIC]
The last thing that we want to do for
our break out game is to add integration with game center.
Game Center is Apple's social integration for games,
where you can share different scores and achievements with all of your friends
in one centralized location across the entire Apple ecosystem.
Adding that to a game can be a real enhancement to it and make it more fun,
because it integrates the other people's experience
with your experience on the device.
High level, what we can do with game center is to improve social interaction.
What we're going to talk about in this lecture is how to achieve that with
achievements and leaderboards.
Actually, leaderboards first, then achievements.
To activate game center, you need to turn on the game center capability in your app.
This is going to do all the work of registering your app with iTunes Connect,
and making sure that all the credentials are shared between the two, so
that then you can use the Game Center.
Let's look at what that looks like in this recorded video of me walking through it.
Within the breakout demo that we have here,
you go and you go to the general properties and
at the top you'll see on the toolbar, let me get there, capabilities.
From here you can select game center, and
that's going to integrate you with the online iTunes Connect.
You select the account that you want to use, and if it's not already registered,
you can go and log in through the Xcode preferences.
And if everything goes okay, you'll be linked in.
Later when you go to iTunes Connect,
you'll find that this game has been registered by its package name.
Also under the general tab.
But before we're ready to do that, we need to think about designing our leaderboard.
A leaderboard allows players to see how well they're doing compared to their
friends and other people around the world.
A leaderboard is basically a high score list.
But depending on the kind of game you have across the wide
breadth of games that are available on IOS.
High score can mean a lot of different things.
So the first thing you need to think about when you design your leaderboard is what
kind of units you're going to be using.
This is probably going to be natural for your game, but
a typical one would be points, the number of points that are scored in your game.
You have to think about what units you use for points.
Is it an integer, meaning there's nothing after the decimal point?
Or are there decimal points in your score?
How high does your score go?
Because that's going to be something that you'll need to indicate.
How low can it go?
What's a reasonable score?
Maybe you don't keep track of points, but maybe you keep track of time,
maybe you have some kind of a course or a race in your game, and
the goal is to get through it as fast as possible.
And so, reporting your score isn't a really a points issue,
it's really a time issue.
Or maybe it's a money issue.
Maybe you are going to report the amount of money that you made
in some kind of a virtual economy.
Maybe in some sort of a betting game that you bet,
I don't know, you do some kind of wagering.
You can use many different currencies to represent your money.
The last thing you have to do is you have to decide if a high score is better or
a low score is better.
Again, this is probably just going to come very naturally of the nature of your game.
If it's a racing game, a lower time is going to be better.
If it's golf, a lower score's going to be better.
If it's pinball, a higher score's going to be better.
But that has to be decided before you register your leaderboard.
In iOS, in the game center, it's possible to have multiple leaderboards.
It might be the case that you would like a leaderboard for
different skill levels of your game.
Maybe you have a beginner, a novice, and expert level of difficulty for your game,
and you'd like to have different leaderboards for each of those.
Maybe you'd like different leaderboards for different devices, or
different leaderboards for
different levels of your game, so you can report high score on a particular level.
Or maybe you'd like different leaderboards to measure different ways of
playing your game.
So maybe you might have a racing game where you want to report the fastest
lap in a sequence of many laps.
Or maybe you want to report your overall time
across several laps around a racecourse.
You could have a leaderboard for both of those, for the fastest lap and for
the fastest overall time.
And finally you have combined leader boards.
These are leader boards that automatically aggregate best scores
from all other minor boards.
So you know, maybe you would have several levels and
some kind of a side scrolled game.
You'd have a lapsed time on each of those,
each of those would end up being the best time in each level.
But then you have an aggregate board, this is what your best time.
I'm getting through all of the levels at once.
So those are some possibilities although we aren't going to talk about them
in this tutorial.
But those are out there if you are interested.
On the flip side, there's achievements.
So, achievements are goals that you can set within a game.
If you have visible achievements, or ones that users know are out there, and
they know this because they can go to Game Center and
look at all the achievements that are possible within a game.
They can possible see them within your game if you implement that, but when you
present achievements to a user, it gives them goals, things that they can try and
do or things that they can aspire to within your game, those are the visible.
But you can also have hidden achievements and these are more like prizes or
rewards that are given to players in order to just surprise them,
delight them, indicate to them that they're making progress.
But they function in a different way.
They're not so much goal setting, as they are prizes, secret prizes.
When you're thinking about achievements,
you could achievements to show the breadth of your game.
So, one thing you can do is use achievement, visible achievements,
to encourage users to try out all the different ways of playing your game.
Maybe there are different ways you can set goals for
yourself, there are other things that you can try and optimize in the game.
You can try and play collaboratively or competitively.
Maybe you can play for giving as many things or
as getting as fast as you want, something like that.
So you can use different kinds of achievements to encourage
trying out different ways of navigating through a game.
You can also use achievements to help players find secret parts of the game or
less frequently explored parts of the game.
Within the ecosystem of achievements, Apple has designed achievements to
have sort of an economic model, or sort of an economy within the game.
And this isn't something that is exposed very clearly to users,
I mean they can see it in game center.
But I think it's more designed to structure achievements across
multiple games.
So each iOS achievement has a number of points associated with it and
when you register them you have to pick how many points they're worth.
Every app can have a total of a thousand achievement points.
Every app can have up to a hundred different achievements.
Each one of those achievements uses a certain amount of points, and you have to
budget them so that you're achievements don't go over a thousand points.
Any single achievement can't have more than a hundred points.
So, for example, You could have ten achievements each worth a hundred points,
and that would add up to a thousand points.
Or you could have a hundred achievements each worth ten points and
that would add up to a thousand.
Or you could use different amounts of points in order to indicate the relative
difficulty of different achievements.
Whatever achievements you design however,
you have got to implement the code within your game in order to keep track of that.
So if you have some sort of a game like Breakout, you want to have all
kinds of achievements like most number of blocks broken within ten seconds or
longest string of blocks broken before the ball was dropped, or
the number of times the ball hits the paddle.
All those things are possible for achievements, but the things that have to
be in your code that you have to write to keep track of when they're in your code.
Some of them can be a little bit tricky to keep track of efficiently,
so whatever you do, you have to keep track of it.
When you decide you want your leaderboard to look like, and what achievements you
want, You register them on iTunes Connect through a web browser.
When you do that, each leaderboard or achievement needs to
have a 1024 x 1024 JPG or PNG in order to represent it.
The documentation on this graphic is a little bit confusing, but this seems to be
the format that works, regardless of what the help says on the website.
Okay, so, let's look at what it looks like to set up a leaderboard and
to set up two achievements for our Breakout game.
We are going to do this through a recording.
A recorded video of going to iTunes Connect to set it up.
First thing you do is you go to iTunes Connect.
I used Google to find it.
When you're there you log in with the account that your game,
that you've registered your game, when you were in the Xcode.
When you registered the capability of Game Center you have to use an account.
You register with the same account and you'll see all the different apps that you
have deployed up until now with that particular account.
Here I have about four.
None of them are real, it's just a recent account.
So, hit the plus in order to start a new app and give it a name and a platform.
And what's going to happen is all of the bundles that you have registered in
Xcode with these parameters are going to show up down below.
So here you can see the Breakout down at the bottom which I just
registered through capabilities is available.
And SKU is,
I forget what it stands for, shop control unit I think, not sure what the k is, but
it's an index that you can set to whatever you want to keep track of things.
Click on Features and then click on Game Center on the left.
And then this is the place where you can set up new leaderboards.
First let's set up a leaderboard by clicking the plus.
We're going to choose a single leaderboard because you can't have a combined
leaderboard without having single leaderboards.
We'll give it a reference name.
And then we're going to give it a leaderboard ID.
That leaderboard ID is how we are going to reference the leaderboard from within
our code.
So we are going to call it high_code.
It will be a type imager and
we are going to submit the most recent score, when we submit.
Score order is high to low.
Actually, I think I got that backwards, because a high score is better.
Then we specify the translation of this leaderboard into a given language.
So I'm going to do it in English, that's high score.
We use integer notation.
We specify the singular and plural description of what this is,
so it's going to be point in English, and points in plural.
Okay, I choose the file.
I go find the 1024 by 1024 image that I set up.
I just came up with a dummy image,
just an image that says leaderboard on it, and save it.
And save it.
And then we'll have the opportunity to submit achievements.
Same thing, we have achievement reference name for us.
But then the achievement ID,
we'll need to use that in our code to reference this achievement.
So we'll set up two achievements, one indicating that the player has broken
one block and another one that's indicated that the player has broken ten blocks.
We'll give them a point value of 1.
We'll make them hidden.
And we'll localize
it to English.
Let's set broke one block before you earn it,
let's try and break one block.
Try break a block and afterwards you broke at least one block
Okay, use another dummy image.
Save that.
Save that.
And then we'll set one up to break 10 blocks.
Break 10 blocks, our achievement ID will be Broke_Ten_Blocks.
Give it a point value of ten and make it hidden.
Come back and give it a point value of ten in a second.
Localize it to English.
Try and break ten blocks and then you broke at least ten blocks.
Pick our dummy image just to get something in there.
Give it ten points and save it.
All right, that registers that leaderboard and those two achievements
within iTunes Connect, and then you can access it in code.
So, in the code, the things that you have to do are first,
you have to register the local player with Game Center.
All right, this is pretty straightforward, but
you want to do it within the View Controller as opposed to a scene,
because this is kind of a game level activity, not a scene level activity.
You'll need to keep track of your achievements and
report them when they occur.
And then you'll need to keep track of your scores and
report them when they're complete or when the game is done.
So in code, this is what it looks like.
To register the local player with Game Center you get the global
instance of the GK local player by calling the local player function and
then you get a pointer to that.
And as soon as you set the authentication handler for that local player,
iOS will go out and register or attempt to authenticate to Game Center.
Game Center is like a single sign on facility within the iOS application.
And so if it works, you'll get a callback indicating that everything is okay.
So this self present view controller, view controller animated yes gives you
the little dropdown that indicates that you logged into View Controller.
There are a couple different flows of how you might want this to work
with respect to errors, and
respect to what happens if the player isn't authenticating to Game Center.
You see I have commented out there some code that will pause your
view in case you're doing some kind of a game or having that banner drop down, or
having some kind of distraction that'll really ruin the game play.
In this case in Breakout since we have that entry screen
before we start the game, I commented out the pause code.
All right, we can also keep track of achievements.
So here's a method that will report the ten block achievement.
And the way we do that is we create a new GKAchievement object.
We allocate it and we initialize it with the string,
the identifier that we just used in iTunes Connect.
So in this case, Broke_10_Blocks.
Once we have a pointer to that we call it scoreAchievement here.
We set how much is complete and when it is complete.
So it's 100% complete and
in this case I want to show a banner and it's going to be a little drop down that
comes down from the top of the screen telling the user that they achieved it.
And then finally we need to report that the user achieved that achievement.
And we're going to do that with the reportAchievements method
in GKAchievement, and
it passes an array of all the achievements that have been achieved.
And in this case it's just one.
And then there's an error handler if it doesn't work for some reason.
Finally, to keep track of scores,
when it's time to report a score you do something very similar.
You initialize a GKScore object.
With the leaderboard identifier that you're using, so high score was the one I
was used in iTunes Connect and that is the one I use here.
You have a pointer to GKscore object and
you set the score.value to whatever the score the player achieved and
then you report it, using the GKScores report scores method.
Passing it in an array of scores, each one associated with a different leaderboard,
in this case we're just passing it in an array with a one-element score.
And then a CompletionHandler that can handle any errors if any arrive.
Optionally, it's also possible to reset all the achievements if you want.
This might be helpful in sort of a preference pane screen if
the user's interested in resetting achievements.
And that's straightforward,
it's just a call to reset achievements to GK achievement.
And you don't actually have to pass it any perimeters except for
a completion handler block because your game is already registered and
the user's already registered in this case.
Okay.
So let's go add this to our Breakout code and
that should finish up our Breakout demo.
So here we are in our Breakout code.
Everything is the same as when we last left it with the exception of two things.
The first thing, is I added a new particle filter based on this,
let's see where is it, based on this graphic, this 100 graphic.
And basically this is just a single particle, that when you hit a block,
pops up a 100, indicating that you got a score of 100 for breaking that block.
The other thing that changed, is last time at the end of the last case study was
having trouble registering the particle filter with the ball.
When the ball hit the bottom of the screen, indicating that the game was over,
I was having trouble getting the particle filter to latch on to show at all.
And at the end of the day, what happened was,
let's see, right here, the particle explosion.
I ended up just having to get rid of the target node.
For some reason I couldn't set the target node to the scene.
It seems like something's wrong there, but I couldn't figure out what it is, so
I just attached the particle explosion to the ball itself.
Okay, so if we go back up to the top of our code,
we know we have these different scores.
We know we have these different achievements.
So the first thing we do is we set up three properties that are going to
track these things.
So blocksBusted is how many blocks you've broken.
That's going to be associated with the score.
blocksBusted1Block is true when you make that achievement.
Busted10Blocks is true when you make that achievement.
When this game scene opens, we're going to go ahead and set all
three of those equal to no blocks busted, that you haven't achieved the achievement.
And we're going to go ahead and
reset the achievement just for teaching purposes here.
I said that we needed to authenticate the player.
So let's go to our game View Controller and show the authentication there.
So in here we need to import game kit in order to get
access to the code that we need.
We're going to get the local,
we're going to get the single instantiation of GK local player here.
So that we can work with it.
We're going to set the local authentication handler equal to some code
that we just showed previously.
We're going to go ahead and leave the view commented out.
So we're not going to pause the game at all when we do our authentication.
So if the thing comes down, the little drop down saying you've registered.
It's going to just interrupt the game if necessary and we'll present it here.
We're not going to do any error handling here,
error handling might be something you'd want to do in a more robust game.
The other thing you might want to do is you want to set a global variable or
global instantiation variable.
Indicating the Game Center's not active so you don't keep track of all the things
that you can be keeping track of if the player is registered at Game Center.
On the other hand it's probably not that big of a deal to keep track of it and
then when you report it, it's just not going to work.
But it probably would flow fine.
Okay so this is the first thing,
we've authenticated the user, we go back to our scene.
We've authenticated our user and we have started keeping track of our achievements.
Let's go ahead and go down and fill out the reset achievements method.
That's going to be at the very bottom, for me.
It doesn't have to be at the bottom, it just is.
Resetting the achievements is just a simple matter of calling
GKAchievement resetAchievementsWithCompletionHandler.
My completion handler doesn't do anything except log the error.
Then let's go back up to the top.
Okay, so we've reset our achievements.
If we think through this,
all the other work has to be done in our collision detection.
Because in a collision detection is when we're going to count everything and
when we're going to report these different achievements.
So let's go down past our creation of all our blocks and our physics bodies and
our friction and our touches all our touches get past that.
Get past our speed, keeping our speed of our ball okay and
get down to where we begin contact.
We know that when a block and
a ball come in to contact there's going to be a collision.
So the first thing that we're going to do is we're going to increase the number of
blocks that have been broken okay, just keep track of that.
And then we're going to say if the number of blocks that has been broken is greater
than or equal to one, and bustedBlock is equal to no because we only want to
report it once if for some reason we double count or we have a race condition.
We're just going to say no if it's equal to no.
If we do hit this condition, we'll set it equal to yes.
So we only end up running this code once.
And we will call our report one block achievement.
All right, let's go down and implement that.
The report one block achievement.
That's going to be down here at the bottom by resetting the code,
by resetting achievements.
And we report a one block achievement,
we get a new GK achievement with our identifier broke_one_block.
We set percent complete equal to 100.
I want to see the little drop down banner, so
I say yes, especially since it's a hidden achievement in this case.
And then we're going to report it with an array that consists of just one element.
Completion handler is just going to log any errors, and when we call this,
it will go ahead and report our achievement directly.
Coming back up to our collision detection We'll say, okay, that's good.
What about if the number of blocks that have been busted is greater than ten?
Well, if we've never reported this before, we'll go ahead and set it equal to yes,
that it has been reported.
And we'll go ahead and call our method report our ten block achievement.
Let's go down and set that up.
Okay, when we report our ten block achievement it's
going to look like the other ones.
The only thing different here is that we're going to be
using broke ten blocks as our identifier.
All right, come back up to where we detected the collision.
All right, that's all fine.
As we go through our collision now we do all of the work of ramping up and
doing the sequences, the explosion, showing the particle score.
So this is the new code that I added that shows that just 100 floating up one time,
that's a particle that only has the 100, and there's only 1 of them that floats up.
Okay, then finally we're going to check whether the game's over.
This was the code that's already there.
We're going to add one line here, which is if the game is over and we're
about to switch to the game won, we're going to go ahead and report our score.
We're going to report our score, and
it's going to be the number of blocks we busted times one hundred.
Let's go and un-comment our report score code, and
it's what we saw in our previous slide.
We identify our leaderboard.
We initialize a GK score object.
We set the value equal to the parameter that was passed in, and we report it.
Our completion handler logs any errors we might get if necessary, but basically,
end of the game, that's what's going to get reported.
There are actually two ways that we can end the game,
this is if you've cleared the entire screen, but
the other way is if you have the ball fall past the paddle onto the bottom.
In that case, you missed the ball.
And, so what we're going to do is we're going to set up an action,
which is to report the score.
This will be a separate action.
What we'll need to do is we will need to add this into the sequence of
actions that we do at the end, so here it is.
Our explode sequence is going to consist of doing
the ramp up sequence and the explosion sequence.
We're going to have the ball, this is the ball, sorry.
So, the ball is going to have a particle emitter on it as the explosion.
It's going to make the explosion noise.
The ball is going to fade out, and then we're going to remove the ball, and
we're going to report our score to the game center,
and then we're going to switch scenes to our game overseer.
Then we're going to run it.
Okay. And, that should be everything
that we need.
So now, if I activate my iPad and we make sure that QuickTime is mirroring it.
There we go.
And we run our game
There's our game, Deep Space Jail Break, and there we go.
We logged into game center.
So, we got the welcome back DJP3, that's my account.
And, a touch to start the screen.
I'm going to try and at least bounce one block off.
Here we go.
[SOUND] Well, you see I got the Broke 1 Block award, and so I got one achievement.
If I had gotten ten, I would have done ten, and I should have gotten 100 or
200 score.
Oops, I just played again.
Let's see if I can.
[SOUND] because I'm resetting the achievements each time I play,
we'll get that broke one block each time.
Now, if I switch over to game center and
I reload our games you can see that the breakout demo now shows up under
game center, and if I click on it you can see the leaderboard.
I've gotten 300 points.
Globally, I'm the high scorer for
this game and I'm the high score of all my friends.
And then, if you switch to achievements, you can see that
I've gotten the Broke 1 Block achievement, you can see the graphic there.
And, then you also have a hidden achievement worth 10 points
that I haven't gotten yet.
Okay, so that's it!
We've leveraged Game Center to improve the social interaction in our game.
It's kind of fun to have the game that has this hidden rewards and
achievements in it.
It's fun to be able to see other players playing it, and see how they're doing it.
However you do game center, the components seems to be well designed.
Again, what we're seeing over and over at Game Center,
the game is really about the design and the code is there to support you.
It's helpful to know how to use the code so
you can design a game that matches what's code supports, but achievements are fine,
but you need to have them well designed to make the game fun.
Finally, the Game Center has some other capabilities that I'm not
mentioning as well.
That includes multiplayer coordination and turn-based games.
That's a little bit more sophisticated than what we have time to do in
this course.
But, it's something to look into if you want to
further improve the social interaction in your games.
So great, that's it for Breakout.
It's a fun case study, it's a full fledged game,
just needs to be put into the store now, and sold for $500 a pop.
Thank you very much for your attention.
[MUSIC]
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