How to detect contact regarding sprite texture - sprite-kit

Question

I have a bullet that should be fired at block. Bullet has 6 different random textures to mimic different bullets. And block has 3 different textures chosen randomly to look like there are 3 different blocks. I want to specify in code that if bullet texture is red, and block texture is red then score should increase, but if bullet is red and block is green it will be the game over. I don't really know how to tell game to do so in didBeginContact.
By now I have this:
In the GameScene & didMoveToView:
struct PhysicsCategory {
static let None : UInt32 = 0
static let All : UInt32 = UInt32.max
static let CgyBlock : UInt32 = 0b1
static let Bullet : UInt32 = 0b10
}
bullet.physicsBody = SKPhysicsBody(texture: bullet.texture, size: self.bullet.size)
bullet.physicsBody?.categoryBitMask = PhysicsCategory.Bullet
bullet.physicsBody?.contactTestBitMask = PhysicsCategory.CgyBlock
bullet.physicsBody?.collisionBitMask = PhysicsCategory.None
bullet.physicsBody?.affectedByGravity = false
bullet.physicsBody?.usesPreciseCollisionDetection = true
In didBeginContact:
func didBeginContact(contact: SKPhysicsContact) {
var firstBody: SKPhysicsBody
var secondBody: SKPhysicsBody
if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
firstBody = contact.bodyA
secondBody = contact.bodyB
} else {
firstBody = contact.bodyB
secondBody = contact.bodyA
}
if ((firstBody.categoryBitMask & PhysicsCategory.CgyBlock != 0) &&
(secondBody.categoryBitMask & PhysicsCategory.Bullet != 0))
//and here I suppose I need to implement somehow something like
// && (bullet.texture = "redBullet") && (CgyBlock.texture = "greenBlock" || "blackBlock")
{
gameOver()
}
But I know it will not work. I also tried to make a switch statement inside curly brackets and it didn't work either. How to implement that?
Update: This is how a block is made:
var cgyBlock = SKSpriteNode()
let cgyArray = ["cyanBox", "greenBox", "yellowBox"]
func addCgyLine () {
cgyBlock = SKSpriteNode(imageNamed: "cyanBox")
var randomCGY = Int(arc4random_uniform(3))
cgyBlock.texture = SKTexture(imageNamed: cgyArray[randomCGY])
cgyBlock.physicsBody = SKPhysicsBody(texture: cgyBlock.texture, size: cgyBlock.size)
cgyBlock.physicsBody?.dynamic = true
cgyBlock.physicsBody?.categoryBitMask = PhysicsCategory.CgyBlock
cgyBlock.physicsBody?.contactTestBitMask = PhysicsCategory.Bullet
cgyBlock.physicsBody?.collisionBitMask = PhysicsCategory.None
cgyBlock.position = CGPointMake(size.width + cgyBlock.size.width/2, CGRectGetMidY(self.frame) + 60)
addChild(cgyBlock)
let actionMove = SKAction.moveTo(CGPoint(x: -cgyBlock.size.width/2, y: CGRectGetMidY(self.frame) + 60), duration: 3)
let actionDone = SKAction.removeFromParent()
cgyBlock.runAction(SKAction.sequence([actionMove, actionDone]))
SKActionTimingMode.EaseOut
}
And then I do runAction in didMoveToView.
Bullets:
var cannon = SKSpriteNode(imageNamed: "cannon")
var bulletInCannon = SKSpriteNode()
var bullet = SKSpriteNode()
let bulletArray = ["redBullet","magentaBullet", "blueBullet", "cyanBullet", "greenBullet", "yellowBullet"]
//didMoveToView:
var randomBullet = Int(arc4random_uniform(6))
bulletInCannon = SKSpriteNode(imageNamed: bulletArray[randomBullet])
bulletInCannon.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame))
addChild(bulletInCannon)
//touchesEnded:
var randomBullet = Int(arc4random_uniform(6))
bullet = SKSpriteNode(texture: bulletInCannon.texture)
bullet.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame))
bullet.name = bulletArray[randomBullet]
bullet.physicsBody = SKPhysicsBody(texture: bullet.texture, size: self.bullet.size)
bullet.physicsBody?.dynamic = true
bullet.physicsBody?.categoryBitMask = PhysicsCategory.Bullet
bullet.physicsBody?.contactTestBitMask = PhysicsCategory.CgyBlock
bullet.physicsBody?.collisionBitMask = PhysicsCategory.None
bullet.physicsBody?.affectedByGravity = false
bullet.physicsBody?.usesPreciseCollisionDetection = true
addChild(bullet)
bulletInCannon.texture = SKTexture(imageNamed: bulletArray[randomBullet])

Answer 1

Few ways to go :
You can use node's userData property.
bullet.userData = ["type" : "white"]
To access it:
println(bullet.userData?["type"])
You can create custom Bullet class which is subclass of SKSpriteNode and create property called "type", and in didBeginContact to access that property.
class Bullet: SKSpriteNode {
var type:String = ""
init(type:String) {
self.type = type //later you are accessing this with bulletNode.type
//This is just an simple example to give you a basic idea what you can do.
//In real app you should probably implement some kind of security check to avoid wrong type
let texture = SKTexture(imageNamed: type)
super.init(texture: texture, color: nil, size: texture.size())
}
required init(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
You can use bullet.name property as well, and on creation to set it appropriately based on bullet/block colour. Later in didBeginContact you will check bullet.name to find out the bullet type. Same goes for blocks.
func spawnBulletWithType(type:String) -> SKSpriteNode{
//set texture based on type
//you can pass here something like white_bullet
let atlas = SKTextureAtlas(named: "myAtlas")
//here, if passed white_bullet string, SpriteKit will search for texture called white_bullet.png
let bullet = SKSpriteNode(texture:atlas.textureNamed(type))
bullet.name = type // name will be white_bullet, and that is what you will search for in didBeginContact
bullet.physicsBody = SKPhysicsBody(texture: bullet.texture, size: bullet.size)
bullet.physicsBody?.categoryBitMask = PhysicsCategory.Bullet
bullet.physicsBody?.contactTestBitMask = PhysicsCategory.CgyBlock
bullet.physicsBody?.collisionBitMask = PhysicsCategory.None
bullet.physicsBody?.affectedByGravity = false
bullet.physicsBody?.usesPreciseCollisionDetection = true
return bullet
}
EDIT:
Based on your recent comments you could probably go with this:
let bulletArray = ["redBullet","magentaBullet", "blueBullet", "cyanBullet", "greenBullet", "yellowBullet"]
//didMoveToView:
var randomBullet = Int(arc4random_uniform(6))
let bulletType = bulletArray[randomBullet]
bulletInCannon.name = bulletType
bulletInCannon = SKSpriteNode(imageNamed: bulletType )
bulletInCannon.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame))
addChild(bulletInCannon)
//touchesEnded:
var randomBullet = Int(arc4random_uniform(6))
bullet = SKSpriteNode(texture: bulletInCannon.texture)
bullet.name = bulletInCannon.name
bullet.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame))
bullet.physicsBody = SKPhysicsBody(texture: bullet.texture, size: self.bullet.size)
bullet.physicsBody?.dynamic = true
bullet.physicsBody?.categoryBitMask = PhysicsCategory.Bullet
bullet.physicsBody?.contactTestBitMask = PhysicsCategory.CgyBlock
bullet.physicsBody?.collisionBitMask = PhysicsCategory.None
bullet.physicsBody?.affectedByGravity = false
bullet.physicsBody?.usesPreciseCollisionDetection = true
addChild(bullet)
let bulletType = bulletArray[randomBullet]
bulletInCannon.texture = SKTexture(imageNamed: bulletType)
bulletInCannon.name = bulletType

Answer 2

First you need to define a class for bullets and Blocks
Then you may define a TextureTypes to store your texture types (red,green,…) and set whatever your random method generates into a class variable of this type.
Then you should manage the contact and find out what are the nodes for BodyA and BodyB. after that it is easy to do what ever you like according to the texturetype of your node,
to clarify the code I have defined Textures as a new Type
enum TextureTypes: String {
case Red,Green
var description:String {
switch self {
case Red:return “Red"
case Green:return “Green”
case Green:return “Blue"
}
}
}
Blockclass and BulletClass both hasto inherit from SKNode cause they are a node!
class BlockClass:SKNode {
var NodesTexture : TextureTypes = TextureTypes.Red
}
class BulletClass:SKNode {
var NodesTexture : TextureTypes = TextureTypes.Red
}
write the following codes into your didBeginContact method to detect the TextureType of your Node
if (contact.bodyA.categoryBitMask == PhysicsCategory.Bullet) &&
(contact.bodyB.categoryBitMask == PhysicsCategory.CgyBlock)
{
Ablock = (BlockClass *) contact.bodyB.node;
Abullet = (BulletClass *) contact.bodyA.node;
}
if (contact.bodyA.categoryBitMask == PhysicsCategory.CgyBlock) &&
(contact.bodyB.categoryBitMask == PhysicsCategory.Bullet)
{
Ablock = (BlockClass *) contact.bodyA.node;
Abullet = (BulletClass *) contact.bodyB.node;
if ( Ablock.NodesTexture = TextureTypes.Red )
{
NSLOG(“A Red Block Detected”)
}
}
Do not forget to define your blocks and bullets of type BlocksClass and BulletClass