cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   bobueland
   Member

   I have two overlapping buttons called B1 and B2. (The first has width 80 and the second 160 pixels. Both have height 24 pixels.) A part of B2 overlaps B1. B2 has higher z-order so it's on top. To my surprise, when I click on the overlapping area the button B1 is activated. I think that it would be appropriate to activate button B2, since it's on top. That is how it functions in real world, and that is how users would expect it to be. Why this awkward behavior and and how do I fix it? The code is below. Thanks Bob

   //  HelloWorldLayer.h
   #import "cocos2d.h"
   
   @interface HelloWorld : CCLayer
   {
   }
   +(id) scene;
   @end
   
   //  HelloWorldLayer.m
   #import "HelloWorldScene.h"
   
   @implementation HelloWorld
   
   +(id) scene
   {
   	// create a 'scene' and add a layer to it
   	CCScene *scene = [CCScene node];
   	HelloWorld *layer = [HelloWorld node];
   	[scene addChild: layer];
   	return scene;
   }
   
   - (void)b1Tapped:(id)sender {
       NSLog(@"b1Tapped");
   }
   
   - (void)b2Tapped:(id)sender {
       NSLog(@"b2Tapped");
   }
   
   -(void) createButtons
   {
   	// button B1
   	CCMenuItem *b1MenuItem = [CCMenuItemImage itemFromNormalImage:@"B1.png" selectedImage:@"B1Sel.png" target:self selector:@selector(b1Tapped:)];
   	b1MenuItem.position = ccp(60, 60);
   
   	// button B2
   	CCMenuItem *b2MenuItem = [CCMenuItemImage itemFromNormalImage:@"B2.png" selectedImage:@"B2Sel.png" target:self selector:@selector(b2Tapped:)];
   	b2MenuItem.position = ccp(150, 60);
   
   	// add buttons to a menu
   	CCMenu *buttonMenu = [CCMenu menuWithItems:b1MenuItem, b2MenuItem, nil];
   	buttonMenu.position = CGPointZero;
   	[self addChild:buttonMenu];
   }
   
   -(id) init
   {
   	if( (self=[super init] )) {
   		[self createButtons];
   	}
   	return self;
   }
   
   - (void) dealloc
   {
   	[super dealloc];
   }
   
   @end

   Posted 1 year ago #
2. 

   Richard
   Member

   Hi,

   I've just come across the same problem. I've think I've traced down what is causing it.

   CCMenu basically adds all the CCMenuItems it is given as children with increasing Z order, so the first added items are at the bottom of the pile visually.

   But in its "-(CCMenuItem *) itemForTouch: (UITouch *) touch" method it goes forward through the list of children to find the first one that contains the touch point of interest, so the lower (in z terms) item will be chosen by the touch.

   To fix it I would suggest altering the "CCARRAY_FOREACH(children_, item)" in itemForTouch to run through the list of children backwards. There doesn't appear to be a CCARRAY_FOREACH_BACKWARDS macro so one would have to be written (or the functionality anyway put into that touch function).

   I'm lucky that I can get away with the behaviour as is, as I don't like editing the main Cocos files.

   Posted 1 year ago #
3. 

   ColdLogic
   Member

   In CCArray.h add this macro:

   #define CCARRAY_FOREACH_REVERSE(__array__, __object__)				\
   if (__array__ && __array__->data->num > 0)							\
   for(id *__arr__ = __array__->data->arr + __array__->data->num-1, *end = __array__->data->arr;	\
   	__arr__ >= end && ((__object__ = *__arr__) != nil || true);				\
   	__arr__--)

   In CCMenu.m, replace the itemForTouch: function with. The only change being the type of macro that is called (changed from CCARRAY_FOREACH to CCARRAY_FOREACH_REVERSE)

   -(CCMenuItem *) itemForTouch: (UITouch *) touch
   {
   	CGPoint touchLocation = [touch locationInView: [touch view]];
   	touchLocation = [[CCDirector sharedDirector] convertToGL: touchLocation];
   
   	CCMenuItem* item;
   	CCARRAY_FOREACH_REVERSE(children_, item){
   		// ignore invisible and disabled items: issue #779, #866
   		if ( [item visible] && [item isEnabled] ) {
   
   			CGPoint local = [item convertToNodeSpace:touchLocation];
   			CGRect r = [item rect];
   			r.origin = CGPointZero;
   
   			if( CGRectContainsPoint( r, local ) )
   				return item;
   		}
   	}
   	return nil;
   }

   Posted 2 months ago #

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