iPhone Cocos2d Loading Scenes

Question

I copied the code from the ParticleDemo implementation into my project and tried to make it work. I want that when I click an image it should change/replace the scene. For some reason the scene is not getting replaced. Here is my implementation:

//
//  HelloWorldLayer.h
//  FirstCocoaApplication
//
//  Created by Mohammad Azam on 8/27/10.
//  Copyright HighOnCoding 2010. All rights reserved.
//

// When you import this file, you import all the cocos2d classes
#import "cocos2d.h"

// HelloWorld Layer
@interface HelloWorld : CCLayer
{
}

// returns a Scene that contains the HelloWorld as the only child
+(id) scene;

@end

@class Emitter;

@interface ParticleDemo : CCColorLayer
{
CCParticleSystem *emitter;
CCSprite *background;
}

@property (readwrite, retain) CCParticleSystem *emitter; 

@end

@interface DemoFire : ParticleDemo
{}
@end

And here is the .m file:

//
//  HelloWorldLayer.m
//  FirstCocoaApplication
//
//  Created by Mohammad Azam on 8/27/10.
//  Copyright HighOnCoding 2010. All rights reserved.
//

// Import the interfaces
#import "HelloWorldScene.h"

Class nextAction()
{
    NSLog(@"next action fired");

    NSString *r = @"DemoFire";
    Class c = NSClassFromString(r);

    return c;
}

@implementation ParticleDemo

@synthesize emitter; 

-(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:@"Particle Demo" fontName:@"Marker Felt" fontSize:64];

        //CCScene *s = [CCScene node];

CCMenuItemImage *item1 = [CCMenuItemImage itemFromNormalImage:@"f1.png" selectedImage:@"f1.png" target:self selector:@selector(nextCallback:)];

        CGSize s = [[CCDirector sharedDirector] winSize];

        CCMenu *menu = [CCMenu menuWithItems:item1,nil];
        menu.position = CGPointZero;
        item1.position = ccp(s.width/2 - 100,30); 

        [self addChild:menu z:100];

        //[s addChild: [nextAction() node]];
        //[[CCDirector sharedDirector] replaceScene: s];

        // 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;
}

- (void) dealloc
{
    [emitter release];
    [super dealloc];
}

-(void) nextCallback: (id) sender
{
    NSLog(@"nextCallback fired!");

    CCScene *s = [CCScene node];
    [s addChild: [nextAction() node]];
    [[CCDirector sharedDirector] replaceScene: s];
}

-(void) setEmitterPosition
{
    if(CGPointEqualToPoint(emitter.centerOfGravity, CGPointZero))
        emitter.position = ccp(200,70);
}

@end

@implementation DemoFire 

-(void) onEnter
{
    NSLog(@"demo fire onenter fred"); 

    [super onEnter];
    self.emitter = [CCParticleFire node];
    [background addChild:emitter z:10]; 

    emitter.texture = [[CCTextureCache sharedTextureCache] addImage:@"fire.pvr"];
    CGPoint p = emitter.position;
    emitter.position = ccp(p.x, 100); 

    [self setEmitterPosition];
}

@end

// HelloWorld implementation
@implementation HelloWorld

+(id) scene
{
    // 'scene' is an autorelease object.
    CCScene *scene = [CCScene node];

    // 'layer' is an autorelease object.
    ParticleDemo *layer = [ParticleDemo node];

    // add layer as a child to scene
    [scene addChild: layer];

    // return the scene
    return scene;
}

// 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

// CLASS IMPLEMENTATIONS
@implementation AppController

- (void) applicationDidFinishLaunching:(UIApplication*)application
{
    // CC_DIRECTOR_INIT()
    //
    // 1. Initializes an EAGLView with 0-bit depth format, and RGB565 render buffer
    // 2. EAGLView multiple touches: disabled
    // 3. creates a UIWindow, and assign it to the "window" var (it must already be declared)
    // 4. Parents EAGLView to the newly created window
    // 5. Creates Display Link Director
    // 5a. If it fails, it will use an NSTimer director
    // 6. It will try to run at 60 FPS
    // 7. Display FPS: NO
    // 8. Device orientation: Portrait
    // 9. Connects the director to the EAGLView
    //
//  CC_DIRECTOR_INIT();

    // Obtain the shared director in order to...
    CCDirector *director = [CCDirector sharedDirector];

    // Turn on display FPS
    [director setDisplayFPS:YES];

    // Default texture format for PNG/BMP/TIFF/JPEG/GIF images
    // It can be RGBA8888, RGBA4444, RGB5_A1, RGB565
    // You can change anytime.
    [CCTexture2D setDefaultAlphaPixelFormat:kCCTexture2DPixelFormat_RGBA8888];  

    CCScene *scene = [CCScene node];
    [scene addChild: [nextAction() node]];

    [director runWithScene: scene];
}

// getting a call, pause the game
-(void) applicationWillResignActive:(UIApplication *)application
{
    [[CCDirector sharedDirector] pause];
}

// call got rejected
-(void) applicationDidBecomeActive:(UIApplication *)application
{
    [[CCDirector sharedDirector] resume];
}

-(void) applicationDidEnterBackground:(UIApplication*)application
{
    [[CCDirector sharedDirector] stopAnimation];
}

-(void) applicationWillEnterForeground:(UIApplication*)application
{
    [[CCDirector sharedDirector] startAnimation];
}

- (void)applicationWillTerminate:(UIApplication *)application
{
    [[CCDirector sharedDirector] end];
}

// purge memory
- (void)applicationDidReceiveMemoryWarning:(UIApplication *)application
{
    [[CCDirector sharedDirector] purgeCachedData];
}

// next delta time will be zero
-(void) applicationSignificantTimeChange:(UIApplication *)application
{
    [[CCDirector sharedDirector] setNextDeltaTimeZero:YES];
}

@end

In the AppDelegate file I have setup to load the ParticleDemo as the current scene!

Answer 1

The cocos2d test projects are very bad examples to start a project from. Their intent is to test certain aspects of the code, and just those aspects you should look at and possibly copy. The way the cocos2d testcases are set up doesn't make for a good, clean project though. There are many shortcuts, like putting everything into one file and relying on the left/right buttons to be there to change testcases (I believe that's where the nextAction class comes into play).

I recommend you install the cocos2d Xcode project templates and start with the cocos2d Application project: http://www.learn-cocos2d.com/knowledge-base/cocos2d-iphone-faq/learn-cocos2d-public-content/manual/cocos2d-general/15838-how-to-install-the-cocos2d-xcode-project-templates/

What I see from your code is that the layer doesn't have

self.isTouchEnabled = YES

and it also doesn't have the regular touch input event methods (ccTouchesBegan etc.) added to it. So it will never react to touch input in the first place, let alone call any method that calls replaceScene.