Add SKSpriteNode children back to the parent after removing - ios

Question

I'm working on a game that has 3 clouds in the background which are each SKSpriteNodes. In order to create a parallax effect I'm moving them down the screen as the character is moving up (the screen is moving up as well).
I removing them in the update method after they reach the bottom of the screen. I would like to add them back at a Y position 20px above the viewable scene so that would be 500x on an iPhone 4 and 588px on a iPhone 5. Then just repeat over and over.
Then only way I can think of to do this is to chain SKActions and run a sequence, but I don't think that is the best way. I'm trying to find a way to add them back after they have been removed in the update method.
-(id)initWithSize:(CGSize)size {
...
//Moving Clouds
[self performSelector:#selector(createClouds) withObject:nil afterDelay:.2];
}
-(void)createClouds {
SKSpriteNode *cloud1 = [SKSpriteNode spriteNodeWithImageNamed:#"cloud1"];
cloud1.position = CGPointMake(40, 200);
cloud1.xScale = .5;
cloud1.yScale = .5;
cloud1.name = #"Cloud1";
cloud1.zPosition = 0;
SKAction *moveCloud1 = [SKAction moveToY:-20 duration:15];
[cloud1 runAction:[SKAction repeatActionForever:moveCloud1]];
[self addChild:cloud1];
SKSpriteNode *cloud2 = [SKSpriteNode spriteNodeWithImageNamed:#"cloud2"];
cloud2.position = CGPointMake(300, 320);
cloud2.xScale = .5;
cloud2.yScale = .5;
cloud2.name = #"Cloud2";
cloud2.zPosition = 0;
SKAction *moveCloud2 = [SKAction moveToY:-40 duration:15];
[cloud2 runAction:[SKAction repeatActionForever:moveCloud2]];
[self addChild:cloud2];
SKSpriteNode *cloud3 = [SKSpriteNode spriteNodeWithImageNamed:#"cloud3"];
cloud3.position = CGPointMake(200, 450);
cloud3.xScale = .5;
cloud3.yScale = .5;
cloud3.name = #"Cloud3";
cloud3.zPosition = 0;
SKAction *moveCloud3 = [SKAction moveToY:-200 duration:20];
[cloud3 runAction:[SKAction repeatActionForever:moveCloud3]];
[self addChild:cloud3];
}
-(void)update:(CFTimeInterval)currentTime {
....
// Remove Cloud from parent
[self enumerateChildNodesWithName:#"Cloud1" usingBlock:^(SKNode *node, BOOL *stop) {
if (node.position.x < 0 || node.position.y < 0) {
[node removeFromParent];
//Add node back to the scene at a Y position above the screen then move
// the cloud downwards again. Repeat Forever.
// Exp: Move Cloud 1 to X position 40, Y position 500 (20 pixels above the top of the screen for an iPhone 4s)
}
else {
// Do something?
}
}];

Answer 1

You can add an SKAction to move your cloud back to the top:
SKSpriteNode *cloud1 = [SKSpriteNode spriteNodeWithImageNamed:#"cloud1"];
cloud1.position = CGPointMake(40, 200);
cloud1.xScale = .5;
cloud1.yScale = .5;
cloud1.name = #"Cloud1";
cloud1.zPosition = 0;
SKAction *moveCloud1 = [SKAction moveToY:-20 duration:15];
// SKAction to move cloud back to top of screen
SKAction *moveToTop = [SKAction moveToY:CGRectGetHeight(self.frame)+20 duration:0];
SKAction *cloud1Action = [SKAction sequence:#[moveCloud1, moveToTop]];
[cloud1 runAction:[SKAction repeatActionForever:cloud1Action]];
You won't need the code in the update method.

Answer 2

I think you can simply change the position
Also, use CGRectGetMinY to use relative positioning, easier to manage different screen sizes.
And check only the Y position too, because X won't change if they're moving vertically.
This is my idea:
-(void)update:(NSTimeInterval)currentTime {
for(int i = 1; i<=3; i++){
NSString* cloud = [NSString stringWithFormat:#"Cloud%d",i];
[self enumerateChildNodesWithName:cloud usingBlock:^(SKNode *node, BOOL *stop) {
if (node.position.y < 0) {
node.position = CGPointMake(node.position.x,CGRectGetMaxY(self.frame)+20);
}
}];
}
}