How to rotate SKNode in swift - swift

Question

I want my SKNode To rotate like Image below :)
Image Here
Instead it is rotating around the bottom left corner of the screen!
Click Here To View Video of what is happening that I do not want
How do i get it to rotate counterClockWise or Clockwise in one position like image show above?
Thank you ahead of time for someone who can help me out. not sure if i have to change anchor points or what... thank you
Here is my code below in swift.
import SpriteKit
class GameScene: SKScene, SKPhysicsContactDelegate {
var top = SKSpriteNode()
var bottom = SKSpriteNode()
var line = SKSpriteNode()
var RightSide = SKSpriteNode()
var LeftSide = SKSpriteNode()
var pointBar = SKSpriteNode()
var Second_point_Bar_For_First_Hoop = SKSpriteNode()
override func didMove(to view: SKView) {
physicsWorld.contactDelegate = self
createHoop()
}
func createHoop() {
top = SKSpriteNode(imageNamed: "top")
top.position = CGPoint(x: self.frame.width / 2, y: self.frame.height / 2 + 15)
top.size = CGSize(width: 100, height: 60)
top.zPosition = 0
bottom = SKSpriteNode(imageNamed: "bottom")
bottom.position = CGPoint(x: self.frame.width / 2, y: self.frame.height / 2 - 45)
bottom.size = CGSize(width: 100, height: 60)
bottom.zPosition = 2
LeftSide = SKSpriteNode()
LeftSide.position = CGPoint(x: bottom.position.x - 40, y: bottom.position.y)
LeftSide.size = CGSize(width: 10, height: 10)
LeftSide.zPosition = 0
LeftSide.color = UIColor.blue
RightSide = SKSpriteNode()
RightSide.position = CGPoint(x: bottom.position.x + 40, y: bottom.position.y)
RightSide.size = CGSize(width: 5, height: 10)
RightSide.zPosition = 0
RightSide.color = UIColor.blue
pointBar = SKSpriteNode()
pointBar.position = CGPoint(x: bottom.position.x, y: bottom.position.y + 10)
pointBar.size = CGSize(width: 90, height: 2)
pointBar.zPosition = 100
pointBar.color = UIColor.green
pointBar.zPosition = 100
Second_point_Bar_For_First_Hoop = SKSpriteNode()
Second_point_Bar_For_First_Hoop.position = CGPoint(x: top.position.x, y: top.position.y - 10)
Second_point_Bar_For_First_Hoop.size = CGSize(width: 90, height: 2)
Second_point_Bar_For_First_Hoop.zPosition = 100
Second_point_Bar_For_First_Hoop.color = UIColor.green
Second_point_Bar_For_First_Hoop.zPosition = 100
let hoopPair = SKNode()
hoopPair.addChild(top)
hoopPair.addChild(pointBar)
hoopPair.addChild(Second_point_Bar_For_First_Hoop)
hoopPair.addChild(bottom)
hoopPair.addChild(LeftSide)
hoopPair.addChild(RightSide)
let rotate = SKAction.rotate(byAngle: 1, duration: 5)
let repeatRotation = SKAction.repeatForever(rotate)
hoopPair.run(repeatRotation)
self.addChild(hoopPair)
}
override func update(_ currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
}
}

Answer 1

By default, SKNode anchor point is always 0.5, 0.5. This means you need to work the positions so that everything goes off of the center of the node.
Now everything is going to be relative, so your top and bottom are relative to your hoop node.
Then you need to move the hoopnode position so that it is where you want it.
Here is the code to do that:
(Note I took out all needless code to get your image to rotate on center)
(Another Node: if size does not work, use frame.size)
import SpriteKit
class GameScene: SKScene, SKPhysicsContactDelegate {
var top = SKSpriteNode() var bottom = SKSpriteNode() var line = SKSpriteNode() var RightSide = SKSpriteNode() var LeftSide = SKSpriteNode() var pointBar = SKSpriteNode() var Second_point_Bar_For_First_Hoop = SKSpriteNode()
override func didMove(to view: SKView) {
physicsWorld.contactDelegate = self
createHoop()
}
func createHoop() {
top = SKSpriteNode(imageNamed: "top")
top.size = CGSize(width: 100, height: 60)
top.position = CGPoint(x: 0, y: top.size.height/2)
top.zPosition = 0
bottom = SKSpriteNode(imageNamed: "bottom")
bottom.size = CGSize(width: 100, height: 60)
bottom.position = CGPoint(x: 0, y: -bottom.size.height/2)
bottom.zPosition = 2
let hoopPair = SKNode()
hoopPair.addChild(top)
hoopPair.addChild(bottom)
let rotate = SKAction.rotate(byAngle: 1, duration: 5)
let repeatRotation = SKAction.repeatForever(rotate)
hoopPair.position = CGPoint(x:self.size.width/2,self.size.height/2)
hoopPair.run(repeatRotation)
self.addChild(hoopPair) }
override func update(_ currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
} }

Answer 2

What is the anchor point of the sprite? Sprites rotate about their anchor point and yours appears to be set to (0,0) i.e. the bottom-left corner. If so, try changing it to (0.5,0.5)