My slides for the Intro to iOS Development Presentation

The books I mentioned/recommend:
Aaron Hillegass Objective-C Programming

Beginning iOS 5 Development

Learning Objective-C 2.0

Learning iPad Programming

And here are some sites to brush up on Objective-C:
http://cocoadevcentral.com/d/learn_objectivec/
and the C language:
http://cocoadevcentral.com/articles/000081.php

Last but not least, the Apple docs:
Apple’s Sample iPhone App

How to name your Objective-C Methods

The Objective-C Language

This talk covers the top 10 things you can do to improve performance of your games or apps.

You can get the slides here
The video of the Performance Talk at VTM is here:
Voices That Matter: iOS Developers Conference Session: Getting the Most Out of Cocos2D: Performance Tips and Tricks

A special thanks to the Atlanta iOS Meetup group, for letting me try out and test-run the presentation on them.

Here are the slides and code for the talk.
Hope to see you at the next conference,
Rod

Ray and I are teaching the Beginning iPhone Game Development Workshop with Cocos2D in two locations:

There is a 2 day version:
October 15th and 16th in Denver, Colorado.
Use the code “Prop” to get $75 dollars off the registration

and

There is a 1 day version:
November 11th-13th in Boston, MA (as part of the Voices that Matter Conference)
By the way, if you are going to the Voices that Matter conference, use the code BSTSPK8 to get $150 dollars off the price of the conference.

In short, this is drinking-from-a-firehose, get your hands dirty type of workshop. We lecture for a short bit, show you some sample code/demos, and then you jump into the labs coding a set of mini games to drive home Cocos2D and Chipmunk knowledge. Of course we typically head for some refreshments at the end of the day

You can see more details on the registration page for Denver.
Here is what people said about the course the last time around:

Hope to see you guys in Denver or Boston,
Rod

The blog posts here have been slower then I would like. First we were busy with the book, you know actually writing and coding, and lately I have been taking some time off to rest and recharge, spending time with my two kids. Our older boy is 3, and it has been a world of fun building train tracks and playing with him. Even though I have a terrible Sir Topham Hatt English accent, he does not seem to mind

If you have no idea who Sir Topham Hatt is, just wait until you have kids, especially boys. You will quickly learn to scour youtube for videos of firetrucks, trash compactors, and our favorite, airplanes landing.

Here is a track we were working on a few night ago:

I have gotten more game ideas (no, not train related) while playing with them, and re-discovered the kid in me. I’m sure most parents realize that special opportunity of being a kid once more when playing with your own kids. It is really fun to take some time off from Xcode and clear one’s head a bit.

What about some Cocos2D content? That will have to wait until next week, I’ve got a post underway covering how to convert a Cocos2D+Box2D physics game into a Cocos2D+Chipmunk game. Why would you do such a thing…

Last but not least, I convinced Ray to leave the Northeast for a weekend and come down to Atlanta so we can teach a weekend workshop on Cocos2D (and Chipmunk). There are a couple of seats left, register here.

What inspirations or ideas have you gotten while playing with your kids?

If you are like us, you have been thinking about making your own games since you were a kid. I started with an Apple ][, some of you way earlier and some of you are just now starting. Either way. the hardest part is taking that first step.

Ray and I taught a day long workshop on Learning Cocos2D at the Voices That
Matter iPhone conference called Cocos2D via Minigames back in Seattle earlier this year.

We had a great time, and it was wonderful to really get folks started with Game Dev and see the light bulb moments when they crossed that threshold of “I wish I could make this game”, to “I know I can make this game”. Some attendees even ended up staying up throughout the night after a full day workshop because they wanted to work on their games and apply what they learned. It was really inspirational to see that creative spark, and one of the reasons I really enjoy teaching.

Ray and I are pleased to announce that we are bringing the workshop to Atlanta, GA and expanding it to a full weekend.
The workshop is split between lecture, demos, and labs. We cover the concepts and the demo how to implement it in code, then guide you through hands-on labs in building a series of minigames to re-enforce those concepts. For example, in the first minigame you learn about sprites and actions and movements, then go to build a game about a cat avoiding on-coming cars. We really designed it as hands-on, learn the concepts and code, then turn around and apply it to create a minigame.

There are six minigames in all, several of them fully physics based games.
If you have no Cocos2D experience or even a little, we take you through the Cocos2D basics and then right into animations, scrolling, physics, sounds, and much more.

This session of the Cocos2D via Minigames will be in Atlanta, GA on June 11th and 12th.

If you have been waiting to learn Cocos2D and create your own games, wait no more.

Sign Me Up!

So, do you want to start making your own games? Sign up now on the
EventBrite page!

Use the code prop to save $100 off the price of the workshop. You get that just for reading this far down the post

You should have Xcode installed on your machine prior to the workshop. We’ll be using Xcode 4 for demos and such, but if you’re still using
Xcode 3 it’s OK.  You don’t necessarily need to have Cocos2D installed as we’ll cover how in the class.

Last but not least, Ray and I are glad to have Shawn Grimes helping us out
with the workshop. Shawn will be helping organize the workshop and be a helping hand during the labs, answering your questions along with Ray and I.

Looking forward to seeing you here in Atlanta,
Rod

My talk is on Performance Tips and Tricks for Cocos2D, learn how to keep your game at 60 frames per second even on a iPhone 3G!

On April 8th Ray Wenderlich and I are doing a full day long workshop on learning Cocos2D via MiniGames. It’s part lecture, part hands-on, with lots of sample code and time in Xcode. If you have been waiting to learn Cocos2D this workshop will get you from zero to building your own games in one caffeine filled day. Don’t just take my word on it, see the other great speakers on the schedule here:

Lastly, you can still save $100 off the price with the code SEASPK2

Hope to see you in Seattle,

Rod

As some of may know I come from a certain soccer playing country. We call it futebol, but I’ve lived in the states long enough to call it soccer. Some years ago I injured my L5 disc by playing soccer badly. No, really badly, the kind of soccer playing that would have made me a hit on youtube, luckily those games were not recorded. These days I am mostly pain free, but sitting for long periods is not good. 2010 was worse then most years, I found myself on long periods of time sitting down in long coding and writing sessions. Turns out writing a book takes a ton of time, who knew

I saw some other developers talk about their standing setups, and decided to give it a try. If nothing else it would help keep my keyboard out of reach of our 2 year old. You have no idea how many Xcode compile errors I can get after he gets a hold of my Mac.

I’ve got a Dell 23inch monitor I use as my main display, so I stacked it and the keyboard+mouse on top of some boxes. This worked pretty well, except that the height was not quite right, and I ended up with a sore neck after some long days. During the first week my feet were killing me. I’ve got a carpeted office upstairs, but I found out wearing some flip flops cured the foot pain. You really need some arch support if you are standing most of the day.

Of course the stacked box system was not that convenient, moving to a sitting position required moving the boxes off the desk and being careful not to drop the monitor and Macbook Pro in the process. After a month I bit the bullet and ordered a GeekDesk. I went for the larger desk, as I still do a lot of note taking and design on paper, so I really liked having the extra space. I’ve had the GeekDesk since early December, and I can’t say enough good things about it. It works perfect, and it’s a breeze to move it up and down with the electric motor. Here is the desk in the down position:

So how is my work like nowdays? I stand up almost the entire day. If I am researching something or reading I will usually sit and use the iPad. The rest of the time I’m standing up. I feel a lot more alert, and have been able to cut down some of my coffee intake, which is good. It is a lot harder to slack off and daydream somewhere else when you are standing up, or you will start to lean and fall over.

Standing up all day is not without side effects, I end up dancing a lot more. That’s all I’m going to say about that

Some links on health perils of sitting all day:

Health Issues with Sitting All Day
Sitting = Death

How do you develop code, and what is your setup like?
Rod

This post is part of iDevBlogADay, a group of indie iOS development blogs featuring at least two posts per day. You can keep up with your favorite developers through the iDevBlogADay web site, RSS feed, or Twitter.

In the last post you learned how to create a Cocos2D game for the Mac. For this post I am going to cover how you can add the Box2D Physics engine to your Cocos2D Mac games. It is really pretty easy, here you will learn how to get Box2D integrated into your project and mess with gravity, next week I will cover more about the Box2D Debug Renderer. I’ve tried to make this post somewhat brief, let me know in the comments what else you would like to see as well as any questions.

Step 1 – Copy the Box2D Folders (excluding the TestBed)
Copy the following Folders into your project.

The TestBed for Box2D includes the Box2D Debug Render Engine for iOS using OpenGL ES. Since we are on the Mac, you want to exclude these for the time being, the next post will show you how to add the older OpenGL Debug Render Engine.

Step 2 – Change the Header Search Path

If you try to compile now you will get a ton of compile errors, over 2000K, since your code does not know where to find the Box2D classes. Fortunately this is easy to fix.

Click on your Project, and then the Info button, and search for “Header Search Path”
Add a header search path to the actual folder location for your Box2D source files (that you copied in Step 1). Be sure to check the recursive checkbox.

Step 3 – Changing to Objective-C++

Since Box2D code is in C++, your Objective-C files have to be Objective-C++, which just means you can mix and match Objective-C and C++ code. Simple rename all of your .m files to .mm
In your games you only need to change the .m files to .mm for any that include Box2D or classes which themselves include Box2D (or any C++).

Rename: Main.m, Cocos2DMacGame2AppDelegate.m, HelloWorldScene.m to .mm versions.

Step 4 – Adding Box2D to your Game

Open the HelloWorldScene.h Header file and add:

#import "Box2D.h"
#define PTM_RATIO 32

In the @interface declaration add:

// HelloWorld Layer
@interface HelloWorld : CCLayer
{
	b2World* world;
}

You should be able to Build your project now without any errors. Test it to make sure everything is good before moving to Step 5.

Step 5 – Creating the Box2D world and ground bodies
Here you are going to add some lines to the init method to setup Box2D, and create ground bodies on the edges of the screen. Without ground bodies your box2d bodies/objects will just fall out of view.
Add this inside the init method:

                // Create the Box2D World
		b2Vec2 gravity;
		gravity.Set(0.0f,-10.0f);
		bool doSleep = true;
		world = new b2World(gravity, doSleep);
		world->SetContinuousPhysics(true);
		
		// Define the ground body.
		b2BodyDef groundBodyDef;
		groundBodyDef.position.Set(0, 0); // bottom-left corner
		
		// Call the body factory which allocates memory for the ground body
		// from a pool and creates the ground box shape (also from a pool).
		// The body is also added to the world.
		b2Body* groundBody = world->CreateBody(&groundBodyDef);
		
		// Define the ground box shape.
		b2PolygonShape groundBox;		
		
		// bottom
		groundBox.SetAsEdge(b2Vec2(0,0), b2Vec2(size.width/PTM_RATIO,0));
		groundBody->CreateFixture(&groundBox,0);
		
		// top
		groundBox.SetAsEdge(b2Vec2(0,size.height/PTM_RATIO), b2Vec2(size.width/PTM_RATIO,size.height/PTM_RATIO));
		groundBody->CreateFixture(&groundBox,0);
		
		// left
		groundBox.SetAsEdge(b2Vec2(0,size.height/PTM_RATIO), b2Vec2(0,0));
		groundBody->CreateFixture(&groundBox,0);
		
		// right
		groundBox.SetAsEdge(b2Vec2(size.width/PTM_RATIO,size.height/PTM_RATIO), b2Vec2(size.width/PTM_RATIO,0));
		groundBody->CreateFixture(&groundBox,0);
		
		// Create a Penguin on the middle of the screen
		[self addNewSpriteWithCoords:ccp(size.width/2,size.height/2)];
		
		// Call the update method 60 times a second
		[self scheduleUpdate];

Note the call to [self scheduleUpdate]. This will call the update method in Step 8 where the physics simulation will occur.

Step 6 – Adding the Box2D shape to the Sprites
Add the addNewSpriteWithCoords method above the init method in HelloWorldScene.mm, it builds on the same method you wrote on the previous post, adding a Box2D body for each Penguin.

-(void) addNewSpriteWithCoords:(CGPoint)p {
	
	
	CCSprite *sprite = [CCSprite spriteWithFile:@"penguino1.png"];
	[self addChild:sprite];
	
	sprite.position = ccp( p.x, p.y);
	
	// Define the dynamic body.
	//Set up a 1m squared box in the physics world
	b2BodyDef bodyDef;
	bodyDef.type = b2_dynamicBody;
	
	bodyDef.position.Set(p.x/PTM_RATIO, p.y/PTM_RATIO);
	bodyDef.userData = sprite;
	bodyDef.allowSleep = false;
	b2Body *body = world->CreateBody(&bodyDef);
	
	// Define another box shape for our dynamic body.
	b2PolygonShape dynamicBox;
	dynamicBox.SetAsBox(0.65f, 0.9f);//These are mid points for our 1m box
	
	// Define the dynamic body fixture.
	b2FixtureDef fixtureDef;
	fixtureDef.shape = &dynamicBox;	
	fixtureDef.density = 3.0f;
	fixtureDef.friction = 0.3f;
	fixtureDef.restitution = 0.3f;
	body->CreateFixture(&fixtureDef);
}

Normally you want your bodies to be able to sleep, in this example we don’t because if you left the penguins at rest, changing the gravity would have no effect of them. In other words, having bodies sleep saves CPU cycles, but if you have a world with few collisions (like this example), then you have to be careful not to get your objects stuck. This being an example, the simplest solution is just to not let physics bodies sleep.

Step 7 – Add the handler for the Mouse and Arrow Keys
In this example the arrow keys change the gravity. If you press up, everything will be pulled towards the sky. Be sure to try out the arrow keys, especially with a few penguins on the screen.

-(BOOL)ccMouseDown:(NSEvent *)event {
	CGPoint location = [event locationInWindow];
	CCLOG(@"Mouse Cick X:%f Y:%f",location.x,location.y);
	
	[self addNewSpriteWithCoords:location];
	return YES;
}

-(BOOL) ccKeyDown:(NSEvent *)event
{
	if ([event modifierFlags] & NSNumericPadKeyMask) { // arrow keys have this mask
        NSString *theArrow = [event charactersIgnoringModifiers];
        unichar keyChar = 0;
        if ( [theArrow length] == 0 )
            return YES;            // reject dead keys
        if ( [theArrow length] == 1 ) {
            keyChar = [theArrow characterAtIndex:0];
            if ( keyChar == NSLeftArrowFunctionKey ) {
                CCLOG(@"Left Arrow pressed");
				CGPoint movePosition = ccp(-1,0);
				
				b2Vec2 gravity;
				gravity.Set(-10.0f,0.0f);
				world->SetGravity(gravity);
				
                return YES;
            }
            if ( keyChar == NSRightArrowFunctionKey ) {
                CCLOG(@"Right Arrow pressed");
				CGPoint movePosition = ccp(1,0);
				
				b2Vec2 gravity;
				gravity.Set(10.0f,0.0f);
				world->SetGravity(gravity);
				
				return YES;
            }
            if ( keyChar == NSUpArrowFunctionKey ) {
				CCLOG(@"Up Arrow Pressed");
				CGPoint movePosition = ccp(0,1);
				
				b2Vec2 gravity;
				gravity.Set(0.0f,10.0f);
				world->SetGravity(gravity);
				
                return YES;
            }
            if ( keyChar == NSDownArrowFunctionKey ) {
				CGPoint movePosition = ccp(0,-1);
				
				b2Vec2 gravity;
				gravity.Set(0.0f,-10.0f);
				world->SetGravity(gravity);
				
				CCLOG(@"Down Arrow Pressed");
                return YES;
            }
        }
    }
    return NO;
}

Step 8 – Update Method to simulate the physics
Add this method above init to update the physics simulation and the positions of sprites associated to physics bodies. This is the same update method found in the Cocos2D iOS Box2D Templates.

-(void)update:(ccTime)dt {
	
	//It is recommended that a fixed time step is used with Box2D for stability
	//of the simulation, however, we are using a variable time step here.
	//You need to make an informed choice, the following URL is useful
	//http://gafferongames.com/game-physics/fix-your-timestep/
	
	int32 velocityIterations = 8;
	int32 positionIterations = 1;
	
	// Instruct the world to perform a single step of simulation. It is
	// generally best to keep the time step and iterations fixed.
	world->Step(dt, velocityIterations, positionIterations);
	
	
	//Iterate over the bodies in the physics world
	for (b2Body* b = world->GetBodyList(); b; b = b->GetNext())
	{
		if (b->GetUserData() != NULL) {
			//Synchronize the AtlasSprites position and rotation with the corresponding body
			CCSprite *myActor = (CCSprite*)b->GetUserData();
			myActor.position = CGPointMake( b->GetPosition().x * PTM_RATIO, b->GetPosition().y * PTM_RATIO);
			myActor.rotation = -1 * CC_RADIANS_TO_DEGREES(b->GetAngle());
		}	
	}
	
}

That’s it! Build and Run and click somewhere on the window. You will see a Penguin fall down to the bottom. Try using the arrow keys to have some fun with gravity.

Here is the project source code:
Cocos2DMacGame2 Source

Thanks for reading,
Rod

This post is part of iDevBlogADay, a group of indie iOS development blogs featuring at least two posts per day. You can keep up with your favorite developers through the iDevBlogADay web site, RSS feed, or Twitter.

Step 1 – Getting the latest Cocos2D develop branch
Assuming you have Git installed on your Mac (if not, follow the steps here), in a folder of your choice run:

git clone git://github.com/cocos2d/cocos2d-iphone.git
git checkout develop

The last line is critical, you will want the develop branch with the latest changes to the Mac Xcode Template.

Step 2 – Installing the (new) Cocos2D Templates into Xcode
In the folder you just cloned the develop branch of Cocos2D, run:

sudo ./install-templates.sh

You are half way there, if you restart Xcode you should see the Cocos2D 1.0.0 templates.

Step 3 – Time to create the game shell and add Mr. Penguino
Select New Project in Xcode and choose the cocos2d-Application Mac template.

Give your Project a name, and set the Active Executable to your Project (and not the Cocos2D Libraries).

If you select your project under the Target Executable and click Build and Run you should see the Cocos2D HelloWorld on your Mac.

HelloWorld is always a good sign. This means you have Cocos2D working and running inside your Mac game. Lets add the Penguino, open up the HelloWorldScene.m class and in the init method add the lines:

// Add the Penguino
penguino = [CCSprite spriteWithFile:@"penguino1.png"];
[penguino setPosition:ccp(size.width/2,size.height/2)];
[self addChild:penguino];

Note that

CCSprite *penguino;

should be added as an instance variable in the HelloWordScene.h header file. You should also grab the Penguino1.png image from the Project link at the bottom of the post. This code does nothing more then add a standard Sprite on the middle of the screen.

Step 4 – Implementing Player Controls

Now you just need to implement the touch controls, or accelerometer, oh wait, we are on the Mac and not iOS. Lets go old school and move Penguino around using nothing more then the arrow keys.

Here once more Cocos2D makes it easy to respond to keyboard events.
Two sub-steps to respond to keyboard events.
First, in your layer init, declare that you want to receive the keyboard events, by using:

self.isKeyboardEnabled = YES;

Next you need to add either ccKeyDown, ccKeyUp, or both depending if you care to know when the user releases a particular key.

Lets add two methods above init, one to respond to the keyboard key down events, and another to move our penguin within the screen.

-(void)movePenguin:(CGPoint)directionOffset {
   CGSize size = [[CCDirector sharedDirector] winSize];
   CGPoint penguinPosition = [penguino position];
   float newXPosition = penguinPosition.x + directionOffset.x;
   float newYPosition = penguinPosition.y + directionOffset.y;

   if ((newXPosition < 0.0f) || (newYPosition < 0.0f)) {
     return; // Do not move
   }
   if ((newXPosition > size.width) || (newYPosition > size.height)) {
     return; // Do not move
   }

   [penguino setPosition:ccp(newXPosition,newYPosition)];
}

and the ccKeyDown method:

-(BOOL) ccKeyDown:(NSEvent *)event
{
   //NSLog(@"key down: %@", [event characters] );
   if ([event modifierFlags] & NSNumericPadKeyMask) { // arrow keys have this mask
      NSString *theArrow = [event charactersIgnoringModifiers];
      unichar keyChar = 0;
      if ( [theArrow length] == 0 )
         return YES;            // reject dead keys
      if ( [theArrow length] == 1 ) {
         keyChar = [theArrow characterAtIndex:0];
         if ( keyChar == NSLeftArrowFunctionKey ) {
            CCLOG(@"Left Arrow pressed");
            CGPoint movePosition = ccp(-1,0);
            [self movePenguin:movePosition];
            return YES;
         }
         if ( keyChar == NSRightArrowFunctionKey ) {
            CCLOG(@"Right Arrow pressed");
            CGPoint movePosition = ccp(1,0);
            [self movePenguin:movePosition];
            return YES;
         }
         if ( keyChar == NSUpArrowFunctionKey ) {
            CCLOG(@"Up Arrow Pressed");
            CGPoint movePosition = ccp(0,1);
            [self movePenguin:movePosition];
            return YES;
         }
         if ( keyChar == NSDownArrowFunctionKey ) {
            CGPoint movePosition = ccp(0,-1);
            [self movePenguin:movePosition];
            CCLOG(@"Down Arrow Pressed");
            return YES;
         }
      }
  }
  return NO;
}

The ccKeyDown method has a couple of interesting lines:

First we pull out the event string and ignore any of the modifiers like the Option key. Change this if you care to know if those keys are pressed.

NSString *theArrow = [event charactersIgnoringModifiers];

The second thing to note is we are ignoring every key except the arrow keys. You may want to allow for more keys then just the arrows, so adjust accordingly. Take a look at the EventsTest Target included with Cocos2D-Mac project (that you cloned in Step 1)

If you click build and run you should have Penguino on the center of the screen, and will be able to move him around with the arrow keys.

That’s it for this short Part 1 of getting your Cocos2D game on the Mac. You now have a shell of the game, with a moving Penguin based on the arrow keys. Next week, Box2D physics on the Mac, or if you have other topics/suggestions, let me know in the comments.

Cocos2DMacGame Source

Thanks for reading,
Rod

This post is part of iDevBlogADay, a group of indie iOS development blogs featuring at least two posts per day. You can keep up with your favorite developers through the iDevBlogADay web site, RSS feed, or Twitter.