Swift/SpriteKit Access A Variable Of An Object + Remove A Node - swift

Question

So I have two objects that should lose health points at an collision.
func addPlayer(xPos: CGFloat, yPos: CGFloat){
playerNode = SKSpriteNode(imageNamed: "player")
playerNode.physicsBody = SKPhysicsBody(circleOfRadius: width/2)
playerNode.physicsBody!.affectedByGravity = false
playerNode.physicsBody!.categoryBitMask = PhysicsCategory.Player
playerNode.physicsBody!.contactTestBitMask = PhysicsCategory.Wall | PhysicsCategory.Zombie
playerNode.physicsBody!.collisionBitMask = PhysicsCategory.Wall | PhysicsCategory.Zombie
playerNode.name = "Player"
player = Player(node: playerNode, healthPoints: 100, attack: 10)
playerNode.position.x = xPos
playerNode.position.y = yPos
playerNode.size = CGSize(width: width, height: width)
addChild(playerNode)
}
func addZombie(xPos: CGFloat, yPos: CGFloat){
zombieNode = SKSpriteNode(imageNamed: "zombie")
zombieNode.physicsBody = SKPhysicsBody(circleOfRadius: width/2)
zombieNode.physicsBody!.affectedByGravity = false
zombieNode.physicsBody!.categoryBitMask = PhysicsCategory.Zombie
zombieNode.physicsBody!.contactTestBitMask = PhysicsCategory.Zombie | PhysicsCategory.Player | PhysicsCategory.Wall
zombieNode.physicsBody!.collisionBitMask = PhysicsCategory.Zombie | PhysicsCategory.Player | PhysicsCategory.Wall
zombieNode.name = "Zombie"
zombie = Zombie(node: zombieNode, healthPoints: 50, attack: 5)
Zombies.append(zombie!)
zombieNode.position.x = xPos
zombieNode.position.y = yPos
zombieNode.size = CGSize(width: width, height: width)
addChild(zombieNode)
}
When a collision appears this function get activated:
func didBeginContact(contact: SKPhysicsContact) {
let firstBody = contact.bodyA.node as! SKSpriteNode
let secondBody = contact.bodyB.node as! SKSpriteNode
if(firstBody.name == "Player" && secondBody.name == "Zombie"){
changeHealthPointsForZombieWithNode(secondBody, points: player!.attack)
} else if(firstBody.name == "Zombie" && secondBody.name == "Player"){
changeHealthPointsForPlayer(secondBody, points: zombie!.attack)
print(player!.healthPoints)
}
}
func changeHealthPointsForZombieWithNode(node: SKSpriteNode, points: Int) {
for zombie in Zombies {
if zombie.node == node {
zombie.healthPoints -= points
print(zombie.healthPoints)
if(zombie.healthPoints <= 0){
zombieNode.removeFromParent()
}
return
}
}
}
func changeHealthPointsForPlayer(node: SKSpriteNode, points: Int) {
player!.healthPoints -= points
if(player!.healthPoints <= 0){
playerNode.removeFromParent()
gameOver = true
}
}
I want to subtract the health points of the zombie depending on the attack of the player and other way around. When the player hits the zombie the zombie should lose life points. When the zombie hits the player the player should lose life points. Every player/zombie got health points and an attack value. How do you access them in my didBeginContact function? I also have multiple zombies stored here var Zombies:[Zombie] = [] because every zombie should have its universal values. How is it possible that just the zombie I attack loses health points.
PS: My class Playerlooks like this:
class Player{
var node: SKSpriteNode
var xPos = CGFloat()
var yPos = CGFloat()
var healthPoints: Int
var attack: Int
init(node: SKSpriteNode, healthPoints: Int, attack: Int){
self.node = node
self.healthPoints = healthPoints
self.attack = attack
}
}

Answer 1

First you can do is compare your firstBody or secondBody object (one that would be zombie after checking) with node field in your Zombie object in loop like this:
func changeHelthPointsForZombieWithNode(node: SKSpriteNode, andPoints points: Int) {
for zombie in Zombies {
if zombie.node == node {
zombie.healthPoints -= points
return
}
}
}
func didBeginContact(contact: SKPhysicsContact) {
let firstBody = contact.bodyA.node as! SKSpriteNode
let secondBody = contact.bodyB.node as! SKSpriteNode
if(firstBody.name == "Player" && secondBody.name == "Zombie"){
changeHelthPointsForZombieWithNode(secondBody, andPoints: Player.attack)
} else if(firstBody.name == "Zombie" && secondBody.name == "Player"){
changeHelthPointsForZombieWithNode(firstBody, andPoints: Player.attack)
}
}
This will be work if Zombie is a class type object, if it struct object you will need to use for var i = 0; i < Zombies.count; ++i loop and call object field form Zombies with index i
Second you can append fields you need to change insede the nodes like this:
class ZombieNode: SKSpriteNode {
var healthPoints: Int
var attack: Int
...
// create custom init method with this params
...
}
Then append to scene this objects of this type like this:
func addZombie(xPos: CGFloat, yPos: CGFloat){
var zombieNode = ZombieNode(imageNamed: "zombie", healthPoints: 100, attack: 10)
...
...
addChild(zombieNode)
}
And in this case you have access you need inside you find in didBeginContact method objects like this:
func didBeginContact(contact: SKPhysicsContact) {
let firstBody = contact.bodyA.node as! ZombieNode
let secondBody = contact.bodyB.node as! ZombieNode
if(firstBody.name == "Player" && secondBody.name == "Zombie"){
secondBody.helthPoints -= Player.attack
} else if(firstBody.name == "Zombie" && secondBody.name == "Player"){
firstBody.helthPoints -= Zombie.attack
}
}
Edits for new code:
Your zombie objects are not removed from the scene because you have not deleted them. You have a variable zombieNode, whenever you create Zambia in this line of code:
zombieNode = SKSpriteNode(imageNamed: "zombie")
you every time assign it a new value, and is a result zombieNode is a pointer to the last created node. This approach works with the player because it is single object, and did not accept for a set of objects. In fact every time when your zombie died you tryed to remove this last created object. Thats why this was not worked. To fix it you need to do the following:
First of all you need do remove this line of code:
var zombieNode = SKSpriteNode()
In your addZombie method create new nodes like this:
let zombieNode = SKSpriteNode(imageNamed: "zombie")
And in changeHealthPointsForZombieWithNode method you can remove zombie nodes like this:
if(zombie.healthPoints <= 0){
node.removeFromParent()
}
It would be good as well, remove objects from Zombie array when you remove the node.