Sprite Kit iOS 7.1 crash on removeFromParent
I have updated iPad Air to 7.1 and Xcode to 5.1. Xcode wanted to update my project to recommended settings, I agreed.
After that my game began crashing in a couple of places when I remove node from parent.
That was a surprise for me — there were no crossings before the update. I restored my project and found out what Xcode does to it — only changes Architectures string:
Before:
After:
In the old version there are no crashes. There are no crashes if I remove arm64 support in new version. In the simulator there are no crashes in both new and old versions.
Where should I pay attention in my code?
Code stack:
SpriteKit`SKCSprite::removeSubsprite(SKCSprite*):
0x1859442cc: stp fp, lr, [sp, #-16]!
0x1859442d0: add fp, sp, 0
0x1859442d4: stp x20, x19, [sp, #-16]!
0x1859442d8: sub sp, sp, #16
0x1859442dc: mov x19, x0
0x1859442e0: str x1, [sp, #8]
0x1859442e4: add x20, sp, 8
0x1859442e8: add x0, x19, 544
0x1859442ec: mov x1, x20
0x1859442f0: bl 0x18594872c ; unsigned long std::__1::__tree<SKCSprite*, std::__1::less<SKCSprite*>, std::__1::allocator<SKCSprite*> >::__erase_unique<SKCSprite*>(SKCSprite* const&)
0x1859442f4: add x0, x19, 464
0x1859442f8: mov x1, x20
0x1859442fc: bl 0x185948218 ; std::__1::list<SKCSprite*, std::__1::allocator<SKCSprite*> >::remove(SKCSprite* const&)
0x185944300: ldr x20, [sp, 1]
0x185944304: ldrb w8, [x20, #18]
0x185944308: ldrh w9, [x20, #16]
0x18594430c: orr w8, w9, w8, lsl #16
0x185944310: tbnz w8, #1, 0x185944324 ; SKCSprite::removeSubsprite(SKCSprite*) + 88
0x185944314: ldr x9, [x20, 61]
0x185944318: ldr x9, [x9, 2]
0x18594431c: cbnz x9, 0x185944324 ; SKCSprite::removeSubsprite(SKCSprite*) + 88
0x185944320: tbz w8, #8, 0x185944330 ; SKCSprite::removeSubsprite(SKCSprite*) + 100
0x185944324: mov x0, x19
0x185944328: mov x1, x20
0x18594432c: bl 0x18594828c ; SKCSprite::removeFromOffscreenList(SKCSprite*)
0x185944330: str xzr, [x20, #392]
0x185944334: ldr x8, [x20, 0]
0x185944338: ldr x8, [x8, 10]
0x18594433c: mov x0, x20
0x185944340: blr x8
0x185944344: ldrh w8, [x19, #20]
0x185944348: orr w9, w8, #0x40
0x18594434c: strh w9, [x19, #20]
0x185944350: ldr x8, [x19, 49]
0x185944354: cbz x8, 0x185944388 ; SKCSprite::removeSubsprite(SKCSprite*) + 188
0x185944358: add x9, x19, 392
0x18594435c: ldrh w10, [x8, #20]
0x185944360: orr w10, w10, #0x40
0x185944364: strh w10, [x8, #20]
0x185944368: ldr x8, [x9, 0]
0x18594436c: add x9, x8, 392
0x185944370: ldrh w10, [x8, #20]
0x185944374: orr w10, w10, #0x40
0x185944378: strh w10, [x8, #20]
0x18594437c: ldr x8, [x8, 49]
0x185944380: cbnz x8, 0x18594435c ; SKCSprite::removeSubsprite(SKCSprite*) + 144
0x185944384: ldrh w9, [x19, #20] EXC_BAD_ACCESS here.0x185944388: orr w8, w9, #0x2
0x18594438c: strh w8, [x19, #20]
0x185944390: b 0x185944398 ; SKCSprite::removeSubsprite(SKCSprite*) + 204
0x185944394: ldrh w8, [x19, #20]
0x185944398: tbnz w8, #7, 0x1859443ac ; SKCSprite::removeSubsprite(SKCSprite*) + 224
0x18594439c: orr w8, w8, #0x80
0x1859443a0: strh w8, [x19, #20]
0x1859443a4: ldr x19, [x19, 49]
0x1859443a8: cbnz x19, 0x185944394 ; SKCSprite::removeSubsprite(SKCSprite*) + 200
0x1859443ac: sub sp, fp, #16
0x1859443b0: ldp x20, x19, [sp], #16
0x1859443b4: ldp fp, lr, [sp], #16
0x1859443b8: ret lr
UPDATE: New information:
My error:
Stack:
I found out something wrong. My node I want to remove consists of two SKSpriteNodes (my sprite image and its shadow) and one SKShapeNode (a thin black rope). I tried to replace my SKShapeNode rope with a SKSpriteNode rope and I got success — problem gone.
Code to remove my node from parent:
SKAction *moveCloud = [SKAction moveToX:destinationX duration:moveDuration];
[cloud runAction:moveCloud completion:^{
[cloud removeFromParent];
}];
Code to add a SKShapeNode rope to my node:
- (void)addRopeToCloud:(SKNode *)cloud
{
CGFloat maxY = self.scene.size.height;
CGFloat length = maxY - [self.scene convertPoint:cloud.position fromNode:cloud.parent].y;
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, 0, 0);
CGPathAddLineToPoint(path, NULL, 0, length);
SKShapeNode *rope = [[SKShapeNode alloc] init];
rope.path = path;
rope.strokeColor = [UIColor blackColor];
rope.lineWidth = 0.1;
rope.antialiased = YES;
rope.zPosition = -0.01;
CGFloat threadScale = 1 / cloud.xScale;
rope.xScale = threadScale;
rope.yScale = threadScale;
[cloud addChild:rope];
CGPathRelease(path);
}
Code to add a SKSpriteNode rope to my node, that resolves the problem:
- (void)addRopeToCloud:(SKNode *)cloud
{
CGFloat maxY = self.scene.size.height;
CGFloat length = maxY - [self.scene convertPoint:cloud.position fromNode:cloud.parent].y;
CGSize ropeSize = CGSizeMake(1.5, length);
SKSpriteNode *rope = [SKSpriteNode spriteNodeWithColor:[SKColor blackColor] size:ropeSize];
rope.anchorPoint = CGPointMake(0.5, 0);
CGFloat ropeScale = 1 / cloud.xScale;
rope.xScale = ropeScale;
rope.yScale = ropeScale;
rope.zPosition = -0.01;
[cloud addChild:rope];
}
It looks like something wrong in my SKShapeNode adding code, but I can't understand what exactly is.
It seems to only happen on iOS 7.1. Not sure if it is an Apple bug, but this seems to fix it:
- (void)removeFromParent
{
[self.aShapeNode removeFromParent];
self.aShapeNode = nil;
[super removeFromParent];
}
You can call this method before you dealloc (or present new scene) the SKShapeNodes
- (void)cleanUpChildrenAndRemove:(SKNode*)node {
for (SKNode *child in node.children) {
[self cleanUpChildrenAndRemove:child];
}
[node removeFromParent];
}
I had the same problem but that solved it. My original question:
SKShapeNode producing crash sometimes on dealloc EXC_BAD_ACCESS
I also crash with SKShapeNode when its parent remove from superview in iOS 7.1
My work around is set SKShapeNode property to nil before it remove from parent
Not sure if my situation exactly mimics yours, but I was getting the same error (with the same stack trace) and realized that I had set up two classes that were each keeping the SKShapeNode object as properties. I'm pretty sure that when I called removeFromParent to remove object node in ClassA the object was deallocated. Then, in ClassB, I called self.node = aNewNode (keep in mind that the object that self.node pointed to had been deallocated), the auto-synthesized setter tried to de-allocate node for a second time.
I thought ARC was supposed to keep track of all this, but the bug is very sporadic so I'm honestly not 100% sure what's going on. I have an SKSpriteNode with the same pattern and I have never seen it causing this error. My fix right now has been to make the ClassB property weak, so it's not a problem if self.node has already been deallocated. Hope that helps!