Objective-c – Detecting if a specific sprite was touched on Cocos2d-iphone

cocos2d-iphonecollision-detectioniphoneobjective-c

I was following Ray`s tutorial for making a simple iPhone game (here: http://goo.gl/fwPi) , and decided that i wanted the enemies to be eliminated when they get touched.

My initial approach was to spawn a small CCSprite sprite on the touch location, then use CGRectMake to create a bounding box of said sprite to detect if the enemy sprite was touched. Much like Ray does with the projectile/enemy. But of course, my way of doing it isnt working and i cant dig myself out of this hole.

Here is the relevant code snippet. Any help is appreciated:

- (void)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

    // Choose one of the touches to work with
    UITouch *touch = [touches anyObject];
    CGPoint location = [self convertTouchToNodeSpace: touch];
    location = [[CCDirector sharedDirector] convertToGL:location];
    CCSprite *touchedarea = [CCSprite spriteWithFile:@"Icon-72.png" rect:CGRectMake(location.x, location.y, 2, 2)];
    touchedarea.tag = 2;
    [self addChild:touchedarea];
    [_touchedareas addObject:touchedarea];

}



- (void)update:(ccTime)dt {

    NSMutableArray *touchedareasToDelete = [[NSMutableArray alloc] init];
    for (CCSprite *touchedarea in _touchedareas) {
        CGRect touchedareaRect = CGRectMake(
                                           touchedarea.position.x, 
                                           touchedarea.position.y, 
                                           touchedarea.contentSize.width, 
                                           touchedarea.contentSize.height);

        NSMutableArray *targetsToDelete = [[NSMutableArray alloc] init];
        for (CCSprite *target in _targets) {
            CGRect targetRect = CGRectMake(
                                           target.position.x - (target.contentSize.width/2), 
                                           target.position.y - (target.contentSize.height/2), 
                                           target.contentSize.width, 
                                           target.contentSize.height);

            if (CGRectIntersectsRect(touchedareaRect, targetRect)) {
                [targetsToDelete addObject:target];             
            }                       
        }

        for (CCSprite *target in targetsToDelete) {
            [_targets removeObject:target];
            [self removeChild:target cleanup:YES];                                  
        }

        if (targetsToDelete.count > 0) {
            [touchedareasToDelete addObject:touchedarea];
        }
        [targetsToDelete release];
    }

    for (CCSprite *touchedarea in touchedareasToDelete) {
        [_touchedareas removeObject:touchedarea];
        [self removeChild:touchedarea cleanup:YES];
    }
    [touchedareasToDelete release];
}

Best Solution

That looks like a very difficult way to go about doing it. I havent been coding long myself but maybe the following might help you. lets say u have a nsmutablearray called enemies and you add the new enemy object to this array when ever you create one. enemy object would be a ccnode and have a ccsprite within it called _enemySprite then do the touch

 -(void)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
    {

    NSSet *allTouches = [event allTouches];
    UITouch * touch = [[allTouches allObjects] objectAtIndex:0];
    //UITouch* touch = [touches anyObject];
    CGPoint location = [touch locationInView: [touch view]];
    location = [[CCDirector sharedDirector] convertToGL:location]; 

    int arraysize = [enemies count];
    for (int i = 0; i < arraysize; i++) {


        if (CGRectContainsPoint( [[[enemies objectAtIndex:i] _enemySprite] boundingBox], location)) {

            //some code to destroy ur enemy here


        }
    }
    //  NSLog(@"TOUCH DOWN");

}

hope this helps

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