Too many retains, no releases; is this code correct?

Colin Gilbert

Hi,

I am implementing a simple finger tracker animation (circle fading out) and it seems to work. However, when I run it in instruments, there is no deallocation taking place. Am I doing something wrong? How does a programmer ensure object transiency using Sparrow? Using Sparrow Main 2.01 w/ ARC.

I wish to use many temporary objects in my programming and it would be quite a pain if too many retains end up damaging performance.

Here is my code

//
// Game.m
// AppScaffold
//

#import "Game.h"

// --- private interface ---------------------------------------------------------------------------

@interface Game ()

- (void)setup;
- (void)onImageTouched:(SPTouchEvent *)event;
- (void)onResize:(SPResizeEvent *)event;

@end

// --- class implementation ------------------------------------------------------------------------

@implementation Game
{
    SPSprite *_contents;
    SPTexture * _circleTex;
}

- (id)init
{
    if ((self = [super init]))
    {
        [self setup];
    }
    return self;
}

- (void)dealloc
{
    [Media releaseAtlas];
    [Media releaseSound];
}

- (void)setup
{
    [SPAudioEngine start];

    [Media initAtlas];
    [Media initSound];

    _contents = [SPSprite sprite];
    [self addChild:_contents];

    SPImage *background = [[SPImage alloc] initWithContentsOfFile:@"background.png"];
    [_contents addChild:background];

    _circleTex = [[SPTexture alloc] initWithContentsOfFile:@"fingerCircle.png"];
    [self addEventListener:@selector(onResize:) atObject:self forType:SP_EVENT_TYPE_RESIZE];
    [self addEventListener:@selector(onTouch:) atObject:self forType:SP_EVENT_TYPE_TOUCH];
}

- (void) onTouch: (SPTouchEvent *) event
{
    NSArray * touches = [[event touchesWithTarget:self] allObjects];
    @autoreleasepool {
        for (SPTouch * touch in touches)
            {
                SPPoint * point = [touch locationInSpace:_contents];
                SPImage * fingaTracker = [[SPImage alloc] initWithTexture:_circleTex];
                fingaTracker.x = point.x;
                fingaTracker.y = point.y;
                fingaTracker.pivotX = _circleTex.width * 0.5;
                fingaTracker.pivotY = _circleTex.height * 0.5;

                SPTween * fadeOut = [SPTween tweenWithTarget:fingaTracker time:1.0f];
                [fadeOut animateProperty:@"alpha" targetValue:0.0f];
                [Sparrow.juggler addObject:fadeOut];
                [fingaTracker addEventListener:@selector(removeFromParent) atObject:fingaTracker forType: SP_EVENT_TYPE_REMOVE_FROM_JUGGLER];
                [_contents addChild:fingaTracker];
            }
    }
}

- (void)updateLocations
{
    int gameWidth = Sparrow.stage.width;
    int gameHeight = Sparrow.stage.height;

    _contents.x = (int) (gameWidth - _contents.width) * 0.5;
    _contents.y = (int) (gameHeight - _contents.height) * 0.5;
}

- (void)onResize:(SPResizeEvent *)event
{
    NSLog(@"new size: %.0fx%.0f (%@)", event.width, event.height,
          event.isPortrait ? @"portrait" : @"landscape");

    [self updateLocations];
}

@end

Thank you for your consideration.

Shilo

Hello,

Are the fingaTracker objects being removed from the stage/screen? From the looks of your code, I assume the objects are not being removed as expected. To test if they are being removed, you might want to do something like the below, so you can visually see if the objects are being removed:
[fadeOut animateProperty:@"alpha" targetValue:0.9f];

You are adding an event listener for SP_EVENT_TYPE_REMOVE_FROM_JUGGLER, which is meant to be used for something quite different. To be honest, I have never used that event type.

Try this code instead:

- (void) onTouch: (SPTouchEvent *) event
{
    NSArray * touches = [[event touchesWithTarget:self] allObjects];
    for (SPTouch * touch in touches)
    {
        @autoreleasepool {
            SPPoint * point = [touch locationInSpace:_contents];
            SPImage * fingaTracker = [[SPImage alloc] initWithTexture:_circleTex];
            fingaTracker.x = point.x;
            fingaTracker.y = point.y;
            fingaTracker.pivotX = _circleTex.width * 0.5;
            fingaTracker.pivotY = _circleTex.height * 0.5;

            SPTween * fadeOut = [SPTween tweenWithTarget:fingaTracker time:1.0f];
            [fadeOut animateProperty:@"alpha" targetValue:0.0f];
            fadeOut.onComplete = ^{
                [fingaTracker removeFromParent];
            };

            [_contents addChild:fingaTracker];
            [Sparrow.juggler addObject:fadeOut];
        }
    }
}

Colin Gilbert

Hi,

Unfortunately, this didn't work. It does seem to deallocate, but unfortunately once three fingers touch the screen there is a crash. I also found out that I was using Sparrow 2.0.1 Master (not Stable) branch.

Exception name was EXC_BAD_ACCESS. It seems to be a zombie object problem.

Sparrow Framework source file involved is SPTouchProcessor.m

- (void)processTouches:(NSSet*)touches
{
    NSMutableSet *processedTouches = [[NSMutableSet alloc] init];

    // process new touches
    for (SPTouch *touch in touches)
    {
        SPTouch *currentTouch = nil;

        for (SPTouch *existingTouch in _currentTouches)
        {
            if (existingTouch.phase == SPTouchPhaseEnded || existingTouch.phase == SPTouchPhaseCancelled)
                continue;

            if (existingTouch.nativeTouch == touch.nativeTouch)
            {
                // existing touch; update values
                existingTouch.timestamp = touch.timestamp;
                existingTouch.previousGlobalX = touch.previousGlobalX;
                existingTouch.previousGlobalY = touch.previousGlobalY;
                existingTouch.globalX = touch.globalX;
                existingTouch.globalY = touch.globalY;
                existingTouch.phase = touch.phase;
                existingTouch.tapCount = touch.tapCount;

                if (!existingTouch.target.stage)
                {
                    // target could have been removed from stage -> find new target in that case
                    SPPoint *touchPosition = [SPPoint pointWithX:touch.globalX y:touch.globalY];
                    existingTouch.target = [_root hitTestPoint:touchPosition];
                }

                currentTouch = existingTouch;
                break;
            }
        }

        if (!currentTouch) // new touch <-- EXCEPTION OCCURRED HERE
        {
            SPPoint *touchPosition = [SPPoint pointWithX:touch.globalX y:touch.globalY];
            touch.target = [_root hitTestPoint:touchPosition];
            currentTouch = touch;
        }

        [processedTouches addObject:currentTouch];
    }

    // dispatch events
    for (SPTouch *touch in processedTouches)
    {
        SPTouchEvent *touchEvent = [[SPTouchEvent alloc] initWithType:SP_EVENT_TYPE_TOUCH
                                                              touches:processedTouches];
        [touch.target dispatchEvent:touchEvent];
        [touchEvent release];
    }

    SP_RELEASE_AND_RETAIN(_currentTouches, processedTouches);
    [processedTouches release];
}

Shilo

The bad access crash could be related to this: http://forum.sparrow-framework.org/topic/sptouchevent-to-deallocate-instance#post-18658

If you haven't updated Sparrow in the past 6 days, updating might fix the issue. I still have yet to use Sparrow MRC version.

Colin Gilbert

It works! Thanks!