Weird screen resizing bug when calling shadowCastBitMask= - xcode

Question

I'm making a ball/paddle "breakout" style game for iOS8 where the blocks fall from the top of the screen.
I decided to try Apple's new SKLightNode in sprite-kit and it worked wonderfully, casting a light from the top of the screen:
in levelScene.h:
#import <SpriteKit/SpriteKit.h>
in levelScene.m:
-(id)initWithSize:(CGSize)size {
...
SKLightNode* light = [[SKLightNode alloc] init];
// light.enabled = YES;
light.categoryBitMask = lightCategory;
light.falloff = 1;
light.ambientColor = [UIColor whiteColor];
light.lightColor = [[UIColor alloc] initWithRed:0.0 green:1.0 blue:0.5 alpha:0.5];
light.shadowColor = [[UIColor alloc] initWithRed:0.0 green:0.0 blue:0.0 alpha:0.2];
light.position = CGPointMake(CGRectGetMidX(self.frame), self.frame.size.height - 20);
[self addChild:light];
...
}
and casting a shadow from the paddle near the bottom of the screen:
-(id)initWithSize:(CGSize)size {
...
self.paddle.shadowCastBitMask = lightCategory;
...
}
However, when I try to make my falling blocks cast shadows by defining the shadowCastBitMask of my rectangle (or block) spriteNodes, which are, unlike the paddle, added at various intervals throughout play, I experience a bizarre kind of clipping where the entire screen and all of its contents resize to around 60%-80% of the original size, squashing vertically slightly. It is only for the briefest of moments so I cannot gain a decent idea of what it is even doing to the image, let alone why. I have found nothing relating to this bug online.
I can say that it is reproduced everytime that a block enters from the top of the screen, even the first time, suggesting that it has nothing to do with multiple instances being called simultaneously. Since the paddle (and ball when tested) seems to cast a shadow without problems, I can only assume that it is either something to do with the fact that the call is made during gameplay, not before it has started as is the case with the paddle, or that there is something in my -addRectangle call that I'm missing.
So, here's -(void)addRectangle in its entirety, the shadowCastBitMask=... call is near the end:
- (void)addRectangle {
// Create sprite
self.rectangle = [SKSpriteNode spriteNodeWithImageNamed:#"Rectangle"];
// Determine where to spawn the rectangle along the X axis
int minX = (CGRectGetMinX(self.frame) + (self.rectangle.size.width/2)) ;
int maxX= (( CGRectGetMaxX(self.frame)) - (self.rectangle.size.width)) ;
int actualX = ( arc4random_uniform(maxX) +minX);
// Create the rectangle slightly off-screen
self.rectangle.position = CGPointMake(actualX, self.frame.size.height + self.rectangle.size.height/1);
self.rectangle.zPosition = 5;
// Determine speed of the rectangle
if(multiplier>=29 && multiplier<49){
int minDuration = 5.5;
int maxDuration = 7.0;
int rangeDuration = maxDuration - minDuration;
int actualDuration = (arc4random() % rangeDuration) + minDuration;
// Create the actions
SKAction * actionMove = [SKAction moveTo:CGPointMake(actualX, -self.rectangle.size.height/1) duration:actualDuration];
[self.rectangle runAction:actionMove];
}
if(multiplier>=49 && multiplier < 99){
int minDuration = 4.0;
int maxDuration = 5.0;
int rangeDuration = maxDuration - minDuration;
int actualDuration = (arc4random() % rangeDuration) + minDuration;
// Create the actions
SKAction * actionMove = [SKAction moveTo:CGPointMake(actualX, -self.rectangle.size.height/1) duration:actualDuration];
[self.rectangle runAction:actionMove];
}
if(multiplier>=99){
int minDuration = 3.0;
int maxDuration = 4.0;
int rangeDuration = maxDuration - minDuration;
int actualDuration = (arc4random() % rangeDuration) + minDuration;
// Create the actions
SKAction * actionMove = [SKAction moveTo:CGPointMake(actualX, -self.rectangle.size.height/1) duration:actualDuration];
[self.rectangle runAction:actionMove];
}
else if (multiplier<29){
int minDuration = 6.0;
int maxDuration = 10.0;
int rangeDuration = maxDuration - minDuration;
int actualDuration = (arc4random() % rangeDuration) + minDuration;
// Create the actions
SKAction * actionMove = [SKAction moveTo:CGPointMake(actualX, -self.rectangle.size.height/1) duration:actualDuration];
[self.rectangle runAction:actionMove];
}
self.rectangle.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:self.rectangle.size];
self.rectangle.physicsBody.dynamic = YES;
self.rectangle.physicsBody.restitution = 0.4f;
self.rectangle.physicsBody.density = 1000;
self.rectangle.physicsBody.categoryBitMask = blockCategory;
self.rectangle.physicsBody.contactTestBitMask = bottomCategory | paddleCategory | laserCategory;
self.rectangle.physicsBody.collisionBitMask = 0x0 ;
self.rectangle.physicsBody.affectedByGravity = NO;
//the offending line:
self.rectangle.shadowCastBitMask = lightCategory;
[self addChild:self.rectangle];
[_blocks addObject:self.rectangle];
_EyeLeft = [SKSpriteNode spriteNodeWithImageNamed:#"Eye"];
_EyeLeft.position = CGPointMake(_EyeLeft.parent.position.x-10, _EyeLeft.parent.position.y) ;
// _EyeLeft.zPosition = 7;
_EyeLeft.physicsBody.allowsRotation = YES;
_EyeLeft.name = #"Eye";
[self.rectangle addChild: _EyeLeft];
[_Eyes addObject:_EyeLeft];
_EyeRight = [SKSpriteNode spriteNodeWithImageNamed:#"Eye"];
_EyeRight.position = CGPointMake(_EyeRight.parent.position.x+10, _EyeRight.parent.position.y) ;
// _EyeRight.zPosition = 7;
_EyeRight.physicsBody.allowsRotation = YES;
_EyeRight.name = #"Eye";
// _EyeLeft.physicsBody.angularDamping = 0.2;
[self.rectangle addChild: _EyeRight];
[_Eyes addObject:_EyeRight];
}
The bug is not reproduced if I simply delete the shadowCastBitMask=... call, however then I get no shadows.
I also don't understand why the whole picture would resize, as I am not, as far as I'm aware, calling any commands related to the scale or scene at the time, certainly not triggered by such a call.
Any help at all would be greatly appreciated,
Thanks in advance for your time and any help offered.

Answer 1

I had this problem, I noticed it happened when using a tilemap, so I just used a static big image for the bG and seems to have solved the problem