How to identify specific nodes in SKCamera's view? - swift

Question

I am trying to recycle same SKSpriteNode to make continuous background. I created SKSpriteNode as bg0, bg1, bg2 and positioned them properly when presenting the scene. Somehow, below code ONLY re-positions bg0 once.
cam is SKCameraNode, therefore, I am checking whether camera contains the background nodes. Due to their size, always one of them should not be visible in the camera viewport. However, like I said this only works once and when camera shows recycled bg0 does not recognize it.
Thank you in advance.
PS: I already tried cam.intersects(bg0) as well, got the same result.
func updateBgPos() {
if (player?.position.y)! > self.frame.height {
if !cam.contains(bg0!) {
print("bg0 is not in the scene")
newPosBgY = (bg2?.position.y)! + self.frame.height
bg0?.physicsBody = nil
bg0?.position = CGPoint(x: self.frame.width / 2, y: newPosBgY)
bg0?.physicsBody = bg1?.physicsBody
} else if !cam.contains(bg1!) {
print("bg1 is not in the scene")
newPosBgY = (bg0?.position.y)! + self.frame.height
bg1?.physicsBody = nil
bg1?.position = CGPoint(x: self.frame.width / 2, y: newPosBgY)
bg1?.physicsBody = bg0?.physicsBody
} else if !cam.contains(bg2!) {
print("bg2 is not in the scene")
newPosBgY = (bg1?.position.y)! + self.frame.height
bg2?.physicsBody = nil
bg2?.position = CGPoint(x: self.frame.width / 2, y: newPosBgY)
bg2?.physicsBody = bg1?.physicsBody
}
}
}

Answer 1

Well, finally I've figured it out how to achieve this. I hope this helps someone else.
I initially created and placed two SKSpriteNode as background as bg0 and bg1 like below:
bg0 = SKSpriteNode(imageNamed: "bg0")
bg1 = SKSpriteNode(imageNamed: "bg1")
bg0!.name = "bg0"
bg1!.name = "bg1"
bg0?.scale(to: CGSize(width: sceneWidth, height: sceneHeight))
bg1?.scale(to: CGSize(width: sceneWidth, height: sceneHeight))
bg0?.zPosition = zPosBg
bg1?.zPosition = zPosBg
backgroundArr.append(bg0!)
backgroundArr.append(bg1!)
bg0?.position = CGPoint(x: sceneWidth / 2, y: 0)
bg1?.position = CGPoint(x: sceneWidth / 2, y: sceneHeight)
self.addChild(bg0!)
self.addChild(bg1!)
After, on the update method I called below function:
func updateBgPos() {
guard let playerPosY = player?.position.y else { return }
guard let bg0PosY = bg0?.position.y else { return }
guard let bg1PosY = bg1?.position.y else { return }
if playerPosY - bg0PosY > sceneHeight / 2 + camFollowGap {
print("bg0 is not in the scene")
newPosBgY = bg1PosY + sceneHeight
bg0?.position = CGPoint(x: sceneWidth / 2, y: newPosBgY)
} else if playerPosY - bg1PosY > sceneHeight / 2 + camFollowGap {
print("bg1 is not in the scene")
newPosBgY = bg0PosY + sceneHeight
bg1?.position = CGPoint(x: sceneWidth / 2, y: newPosBgY)
}
}
PS: camFollowGap is CGFloat value that I subtracted when I position my camera to the player. When dealing with continuous background I had to add that value into calculation to avoid positioning delay and appearances of temporary gaps between backgrounds.