title: SpriteKit : sprite positioning
body: <p>I've found lately a <a href="http://digitalbreed.com/2014/how-to-build-a-game-like-flappy-bird-with-xcode-and-sprite-kit" rel="nofollow">tutorial</a> on how to build a game like "flappy bird" using SpriteKit. Instead of implementing the tap-mechanism, I've used the device accelerometer to move the bird, right and left.
  My problem, now, is with generating pipes. The method used in the tutorial creates pipes on the x axe and not the y axe, which I want to do.</p>
  
  <pre><code>-(void)createPipes
  {
     SKTexture* _pipeTexture1 = [SKTexture textureWithImageNamed:@"Pipe1"];
     _pipeTexture1.filteringMode = SKTextureFilteringNearest;
     SKTexture* _pipeTexture2 = [SKTexture textureWithImageNamed:@"Pipe2"];
     _pipeTexture2.filteringMode = SKTextureFilteringNearest;
  
     SKNode* pipePair = [SKNode node];
     pipePair.position = CGPointMake( self.frame.size.width + _pipeTexture1.size.width * 2,   0 );
     pipePair.zPosition = -10;
  
     CGFloat y = arc4random() % (NSInteger)( self.frame.size.height / 3 );
  
     SKSpriteNode* pipe1 = [SKSpriteNode spriteNodeWithTexture:_pipeTexture1];
     [pipe1 setScale:2];
     pipe1.position = CGPointMake( self.frame.size.width/2 -100, self.frame.size.height+250 );
     pipe1.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:pipe1.size];
     pipe1.physicsBody.dynamic = NO;
     [pipePair addChild:pipe1];
  
     SKSpriteNode* pipe2 = [SKSpriteNode spriteNodeWithTexture:_pipeTexture2];
     [pipe2 setScale:2];
     pipe2.position = CGPointMake( self.frame.size.width/2 +100, self.frame.size.height+250 );
     pipe2.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:pipe2.size];
     pipe2.physicsBody.dynamic = NO;
     [pipePair addChild:pipe2];
  
     SKAction* movePipes = [SKAction repeatActionForever:[SKAction moveByX:0 y:-2 duration:0.02]];
     [pipePair runAction:movePipes];
  
     [self addChild:pipePair];
   }
  </code></pre>
  
  <p>My idea is to generate pipes that fall from the "sky" and the bird has to move between the pipes to keep living.
  I hope that the description of my problem was very clear :)
  Thanks</p>
  
  <p><strong>Clarification</strong> : Pipes do fall from the "sky" but the problem lies with their positioning on the screen. When I run the project, there's no gap between the right pipe or the left one. I only see a giant pipe falling, filling, vertically, a good proportion of the screen.</p>