swift images stacking / duplicating - iOS -

i've started coding , first attempt ios game, part of game i'm working on has following elements.

scrolling foreground , background cat jumps when clicked missile raining down above.

i've managed spawn missile every few seconds in doing think i've messed something.

now have 2 errors, first cat, foreground , background images duplicating , stacking on screen , other build error under override func update(currenttime. i've commented out cat's z rotation otherwise game wont build.

if can me work out how fix i'd grateful.

sorry if it's overkill, here code....

import spritekit  class gamescene: skscene, skphysicscontactdelegate {   var cat = skspritenode() var crow = skspritenode() var crowtexture1 = sktexture() var skycolor = skcolor() var moveandremovecrow = skaction() var spawn = skaction() var lastmissileadded : nstimeinterval = 0.0  let missilevelocity : cgfloat = 5.0    override func didmovetoview(view: skview) {      self.addmissile()  }   func addmissile() {     // initializing missile node     var missile = skspritenode(imagenamed: "red-missile")     missile.setscale(0.15)      // adding spritekit physics body collision detection     missile.physicsbody = skphysicsbody(rectangleofsize: missile.size)     //      missile.physicsbody?.categorybitmask = uint32(obstaclecategory)     missile.physicsbody?.dynamic = true     //      missile.physicsbody?.contacttestbitmask = uint32(shipcategory)     missile.physicsbody?.collisionbitmask = 0     missile.physicsbody?.usesprecisecollisiondetection = true     missile.name = "missile"      // selecting random y position missile     var random : cgfloat = cgfloat(arc4random_uniform(300))     missile.position = cgpoint(x: self.frame.size.width / 1.8, y: self.frame.size.height / 1.2 )     self.addchild(missile) }  func moveobstacle() {     self.enumeratechildnodeswithname("missile", usingblock: { (node, stop) -> void in         if let obstacle = node as? skspritenode {             obstacle.position = cgpoint(x: obstacle.position.x - self.missilevelocity, y: obstacle.position.y)             if obstacle.position.x < 0 {                 obstacle.removefromparent()             }         }     })       skycolor = skcolor(red:113.0/255.0, green:197.0/255.0, blue:207.0/255.0, alpha:1.0)     self.backgroundcolor = skycolor      var cattexture1 = sktexture(imagenamed: "cat1")     cattexture1.filteringmode = sktexturefilteringmode.nearest     var cattexture2 = sktexture(imagenamed: "cat2")     cattexture2.filteringmode = sktexturefilteringmode.nearest      var anim = skaction.animatewithtextures([cattexture1, cattexture2], timeperframe: 0.2)     var run = skaction.repeatactionforever(anim)      cat = skspritenode(texture: cattexture1)     cat.position = cgpoint(x: self.frame.size.width / 2.2, y: self.frame.size.height / 7.0 )     cat.runaction(run)      cat.physicsbody = skphysicsbody(circleofradius: cat.size.height / 2.0)     cat.physicsbody!.dynamic = true     cat.physicsbody!.allowsrotation = false      self.addchild(cat)       var groundtexture = sktexture(imagenamed: "ground")     groundtexture.filteringmode = sktexturefilteringmode.nearest      var movegroundsprite = skaction.movebyx(-groundtexture.size().width, y: 0, duration: nstimeinterval(0.01 * groundtexture.size().width))     var resetgroundsprite = skaction.movebyx(groundtexture.size().width, y: 0, duration: 0.0)     var movegroundspritesforever = skaction.repeatactionforever(skaction.sequence([movegroundsprite,resetgroundsprite]))      var i:cgfloat = 0; < 2 + self.frame.size.width / ( groundtexture.size().width); ++i {         var sprite = skspritenode(texture: groundtexture)         sprite.position = cgpointmake(i * sprite.size.width, sprite.size.height / 2)         sprite.runaction(movegroundspritesforever)         self.addchild(sprite)      }      var dummy = sknode()     dummy.position = cgpointmake(0, groundtexture.size().height / 2)     dummy.physicsbody = skphysicsbody(rectangleofsize: cgsizemake(self.frame.size.width, groundtexture.size().height))     dummy.physicsbody!.dynamic = false     self.addchild(dummy)      var skylinetexture = sktexture(imagenamed: "skyline")     skylinetexture.filteringmode = sktexturefilteringmode.nearest      var moveskylinesprite = skaction.movebyx(-skylinetexture.size().width, y: 0, duration: nstimeinterval(0.1 * skylinetexture.size().width))     var resetskylinesprite = skaction.movebyx(skylinetexture.size().width, y: 0, duration: 0.0)     var moveskylinespritesforever = skaction.repeatactionforever(skaction.sequence([moveskylinesprite,resetskylinesprite]))      var i:cgfloat = 0; < 2 + self.frame.size.width / ( skylinetexture.size().width); ++i {         var sprite = skspritenode(texture: skylinetexture)         sprite.zposition = -20;         sprite.position = cgpointmake(i * sprite.size.width, sprite.size.height / 2 + groundtexture.size().height)         sprite.runaction(moveskylinespritesforever)         self.addchild(sprite)     }  }  override func  touchesbegan(touches: set<nsobject>, withevent event: uievent) {     /* called when touch begins */      cat.physicsbody!.velocity = cgvectormake(0, 0)     cat.physicsbody!.applyimpulse(cgvectormake(0, 15))  }  func clamp(min: cgfloat, max: cgfloat, value: cgfloat) -> cgfloat {     if( value > max ) {         return max;     } else if( value < min ) {         return min;     } else {         return value;     }  } override func update(currenttime: cftimeinterval) {     /* called before each frame rendered */     //       cat.zrotation = self.clamp( -1, max: 0.5, value: cat.physicsbody!.velocity.dy * ( cat.physicsbody!.velocity.dy < 0 ? 0.003 : 0.001 ) );     if currenttime - self.lastmissileadded > 1 {         self.lastmissileadded = currenttime + 1         self.addmissile()     }      self.moveobstacle() }   } 

i've figured out,

i had functions in 'didmovetoview'. after moving them outside block code runs smoothly.