Category bitmask for more than one - sprite-kit

Question

What if I have 50 SpriteKit nodes that each of them has a different categorybitmask and I have a ball if the ball collided with one of those 50 SpriteKit nodes it for example change the color of the the collided SpriteKit to for example green
To achieve this I know I have to write the category bitmask of the SpriteKit node in contact bitmask of the ball
The question is what if if I have 50 SpriteKit nodes how can I or do I have to write all of the 50 SpriteKit nodes in the contact bitmask of the ball
I tried using a loop but I didn’t know how to implement it right
And thanks for your help

Answer 1

You can place many nodes under the same categoryBitmask and assign different names to them.
Example:
enum Collision: UInt32{
case ball = 1
case circle = 2
case box = 4
}
Node Examples:
let node1 = SKSpriteNode(imageNamed: "SoccerBall")
node1.name = "SoccerBall"
node1.physicsBody = SKPhysicsBody(circleOfRadius: node1.size.width)
node1.physicsBody?.categoryBitMask = Collision.ball.rawValue
node1.physicsBody?.contactTestBitMask = Collision.circle.rawValue | Collision.box.rawValue
addChild(node1)
let node2 = SKSpriteNode(imageNamed: "TennisBall")
node2.name = "TennisBall"
node2.physicsBody = SKPhysicsBody(circleOfRadius:node2.size.width)
node2.physicsBody?.categoryBitMask = Collision.ball.rawValue
node2.physicsBody?.contactTestBitMask = Collision.circle.rawValue | Collision.box.rawValue
addChild(node2)
let node3 = SKSpriteNode(imageNamed: "CartonBox")
node3.name = "CartonBox"
node3.physicsBody = SKPhysicsBody(rectangleOf: CGSize(width: node.frame.width, height: node.frame.height)
node3.physicsBody?.categoryBitMask = Collision.box.rawValue
node3.physicsBody?.contactTestBitMask = Collision.ball.rawValue
addChild(node3)
let node4 = SKSpriteNode(imageNamed: "TreasureChest")
node4.name = "TreasureChest"
node4.physicsBody = SKPhysicsBody(rectangleOf: CGSize(width: node.frame.width, height: node.frame.height)
node4.physicsBody?.categoryBitMask = Collision.box.rawValue
node4.physicsBody?.contactTestBitMask = Collision.ball.rawValue
addChild(node4)
In your contact function:
func didBegin(_ contact: SKPhysicsContact){
guard let nodeA = contact.bodyA.node else {return}
guard let nodeB = contact.bodyB.node else {return}
if nodeA.name == "SoccerBall" && nodeB.name == "CartonBox"{
//Do Something
}
if nodeA.name == "TennisBall" && nodeB.name == "CartonBox"{
//Do Something
}
if nodeA.name == "SoccerBall" && nodeB.name == "TreasureChest"{
//Do Something
}
}
And so on...
Just remember to add the SKPhysicsContactDelegate to you class Gamescene.