Hello World

Valid for cocos2d v0.99.0 or newer

This example ONLY shows the basic steps to render a label on the screen. Some advanced options regarding the initialization are not present just to simplify the example. Once you understand this example, you can read the hello_actions sample.

File: HelloWorld.m

Like in c / c++ / etc, you need to import some headers.

// Needed for UIWindow, NSAutoReleasePool, and other objects
#import <UIKit/UIKit.h>
 
// Import the interfaces
#import "HelloWorld.h"

The HelloWorld implementation. This is where the magic happens.

// HelloWorld implementation
@implementation HelloWorld
 
// on "init" you need to initialize your instance
-(id) init
{
        // always call "super" init
        // Apple recommends to re-assign "self" with the "super" return value
        if( (self=[super init] )) {
 
                // create and initialize a Label
                CCLabel* label = [CCLabel labelWithString:@"Hello World" fontName:@"Marker Felt" fontSize:64];
 
                // ask director the the window size
                CGSize size = [[CCDirector sharedDirector] winSize];
 
                // position the label on the center of the screen
                label.position =  ccp( size.width /2 , size.height/2 );
 
                // add the label as a child to this Layer
                [self addChild: label];
        }
        return self;
}
 
// on "dealloc" you need to release all your retained objects
- (void) dealloc
{
        // in case you have something to dealloc, do it in this method
        // in this particular example nothing needs to be released.
        // cocos2d will automatically release all the children (Label)
 
        // don't forget to call "super dealloc"
        [super dealloc];
}
@end

This is the Application delegate implementation. Probably all your games will have a similar Application Delegate. For the moment it's not that important if you don't understand the following code.

//
// Application Delegate implementation.
// Probably all your games will have a similar Application Delegate.
// For the moment it's not that important if you don't understand the following code.
//
@implementation AppController
 
// window is a property. @synthesize will create the accesors methods
@synthesize window;
 
// Application entry point
- (void) applicationDidFinishLaunching:(UIApplication*)application
{
        // Try to use CADisplayLink director
        // if it fails (SDK < 3.1) use NSTimer (default) director
        if( ! [CCDirector setDirectorType:CCDirectorTypeDisplayLink] )
                [CCDirector setDirectorType:CCDirectorTypeDefault];
 
        // create an initilize the main UIWindow
        window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
 
        // Attach cocos2d to the window
        [[CCDirector sharedDirector] attachInWindow:window];
 
        // before creating any layer, set the landscape mode
        [[CCDirector sharedDirector] setDeviceOrientation:CCDeviceOrientationLandscapeLeft];
 
        // Make the window visible
        [window makeKeyAndVisible];
 
        // Create and initialize parent and empty Scene
        CCScene *scene = [CCScene node];
 
        // Create and initialize our HelloWorld Layer
        CCLayer *layer = [HelloWorld node];
        // add our HelloWorld Layer as a child of the main scene
        [scene addChild:layer];
 
        // Run!
        [[CCDirector sharedDirector] runWithScene: scene];
}
 
- (void) dealloc
{
        [window release];
        [super dealloc];
}
@end

Since objective-c is also a c / c++ language, the main entry point is still main

 
int main(int argc, char *argv[]) {
	// it is safe to leave these lines as they are.
	NSAutoreleasePool *pool = [NSAutoreleasePool new];
	UIApplicationMain(argc, argv, nil, @"AppController");
	[pool release];
	return 0;
}

And this is the header file:

File: HelloWorld.h

 
// When you import this file, you import all the cocos2d classes
#import "cocos2d.h"
 
// Application Delegate class
@interface AppController : NSObject <UIAccelerometerDelegate, UIAlertViewDelegate, UITextFieldDelegate, UIApplicationDelegate>
{
	// main UIWindow
	// The OpenGL view will be a attached to this UIWindow
	UIWindow *window;
}
 
// Make the main UIWindow a property
@property (nonatomic, retain) UIWindow *window;
@end
 
// HelloWorld Layer
@interface HelloWorld : CCLayer
{
}
@end