Not detecting Collisions properly in Swift - ios

Question

I'm making a game that spawns cubes from the top of the screen, when they are touched they disappear. I'm setting an objects position to the point touched by the user. It runs the function DidBeginContact , but it doesn't seem to detect my two views:
func didBeginContact(contact: SKPhysicsContact) {
var firstBody : SKPhysicsBody = contact.bodyA
var secondBody : SKPhysicsBody = contact.bodyB
print("didbegincontact")
if ((firstBody.categoryBitMask == PhysicsCategory.RedSquare) && (secondBody.categoryBitMask == PhysicsCategory.touchlocation)) || ((firstBody.categoryBitMask == PhysicsCategory.touchlocation) && (secondBody.categoryBitMask == PhysicsCategory.RedSquare)) {
collisionwithredsquare(firstBody.node as! SKSpriteNode)
print("Done")
}
}
It's printing "didBegincontact" so I know that the function is working but the if statement is not.
Here's all the code:
import SpriteKit
struct PhysicsCategory {
static let RedSquare : UInt32 = 1
static let touchlocation : UInt32 = 2
static let BlueSquare : UInt32 = 3
}
class GameScene: SKScene, SKPhysicsContactDelegate {
var animator : UIDynamicAnimator?
let blueSquare = SKSpriteNode()
let redSquare = SKSpriteNode()
var scorenumber = 0
var ground = SKSpriteNode()
var touchpoint = SKSpriteNode()
override func didMoveToView(view: SKView) {
/* Setup your scene here */
physicsWorld.contactDelegate = self
physicsWorld.gravity = CGVector(dx: 1.0, dy: -9.0)
/* let borderBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
// 2. Set the friction of that physicsBody to 0
borderBody.friction = 0
// 3. Set physicsBody of scene to borderBody
self.physicsBody = borderBody */
touchpoint = SKSpriteNode(imageNamed:"Spaceship")
touchpoint.physicsBody?.categoryBitMask = PhysicsCategory.touchlocation
touchpoint.physicsBody?.contactTestBitMask = PhysicsCategory.RedSquare
touchpoint.physicsBody?.affectedByGravity = false
touchpoint.xScale = 0.5
touchpoint.yScale = 0.5
self.addChild(touchpoint)
let width = UInt32(self.frame.size.width)
let X = arc4random() % width
ground = SKSpriteNode(imageNamed: "Ground")
ground.setScale(1.0)
ground.position = CGPoint(x: self.frame.width / 2, y: 5)
ground.physicsBody = SKPhysicsBody(rectangleOfSize: ground.size)
ground.physicsBody?.affectedByGravity = false
ground.physicsBody?.dynamic = false
ground.zPosition = 3
self.addChild(ground)
//INizialize
animator = UIDynamicAnimator(referenceView: self.view!)
//Add Gravity
//animator?.addBehavior(gravity, sprite)
var test = arc4random() % 90
blueSquare.size = CGSize(width: 100, height: 100)
blueSquare.position = CGPoint(x: CGFloat(X), y: 1000)
blueSquare.zRotation = 34
blueSquare.name = "bluecube"
blueSquare.physicsBody = SKPhysicsBody(circleOfRadius: 20)
blueSquare.physicsBody?.affectedByGravity = true
blueSquare.physicsBody?.dynamic = false
blueSquare.color = SKColor.blueColor()
// BlueSquare.physicsBody?.velocity = CGVectorMake(0, 0)
//BlueSquare.physicsBody?.applyImpulse(CGVectorMake(0, -90))
self.addChild(blueSquare)
let X2 = arc4random() % width
redSquare.size = CGSize(width: 100, height: 100)
redSquare.position = CGPoint(x: CGFloat(X2), y: 1000)
redSquare.name = "redcube"
redSquare.physicsBody = SKPhysicsBody(circleOfRadius: 20)
redSquare.physicsBody?.affectedByGravity = true
redSquare.physicsBody?.dynamic = true
redSquare.hidden = false
redSquare.physicsBody?.categoryBitMask = PhysicsCategory.RedSquare
redSquare.physicsBody?.contactTestBitMask = PhysicsCategory.touchlocation
redSquare.color = SKColor.redColor()
self.addChild(redSquare)
let timerAction1 = SKAction.waitForDuration(0.5)
let timerAction2 = SKAction.runBlock(spawning1)
let timerSequence = SKAction.sequence([timerAction1, timerAction2])
runAction(SKAction.repeatActionForever(timerSequence))
}
func didBeginContact(contact: SKPhysicsContact) {
var firstBody : SKPhysicsBody = contact.bodyA
var secondBody : SKPhysicsBody = contact.bodyB
print("didbegincontact")
if ((firstBody.categoryBitMask == PhysicsCategory.RedSquare) && (secondBody.categoryBitMask == PhysicsCategory.touchlocation)) || ((firstBody.categoryBitMask == PhysicsCategory.touchlocation) && (secondBody.categoryBitMask == PhysicsCategory.RedSquare)) {
collisionwithredsquare(firstBody.node as! SKSpriteNode)
print("Done")
}
}
func collisionwithredsquare(redsquare: SKSpriteNode) {
print("Hello")
}
func spawning1() {
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
/* Called when a touch begins */
for touch in touches {
let location = touch.locationInNode(self)
touchpoint.position = location
}
}
func score () {
scorenumber++
print(scorenumber)
}
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
if CGRectIntersectsRect(redSquare.frame, ground.frame) {
redSquare.position = CGPoint(x: redSquare.position.x, y: redSquare.position.y + 10)
}
}
}
Thanks in advance, Niall

Answer 1

You collision categories are wrong. It should be this because you are dealing with 32 bit integers.
struct PhysicsCategory {
static let RedSquare: UInt32 = 0x1 << 1
static let touchlocation : UInt32 = 0x1 << 2
static let BlueSquare : UInt32 = 0x1 << 3
}
If you use your way you would have to write it like this
struct PhysicsCategory {
static let RedSquare: UInt32 = 1
static let touchlocation : UInt32 = 2
static let BlueSquare : UInt32 = 4
static let somethingElse : UInt32 = 8
}
which is more confusing because you cannot just increment the last number by 1.
Than change your collision code to this. This way you dont have to check for both bodies in the if statement.
/// Did Begin Contact
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.RedSquare) && (secondBody.categoryBitMask == PhysicsCategory.touchlocation) {
collisionwithredsquare(firstBody.node) // I aim pretty sure you dont need to cast as SKSpriteNod, because the body its already a SKNode.
print("Done")
}
}
Also on the touchLocaiton sprite you forgot to give it a physics body.
touchpoint.pysicsBody = SKPhysicsBody(..) // FORGOT THIS LINE
touchpoint.physicsBody?.categoryBitMask = PhysicsCategory.touchlocation
touchpoint.physicsBody?.contactTestBitMask = PhysicsCategory.RedSquare
touchpoint.physicsBody?.affectedByGravity = false
This should work now if you are already getting the contact method to be called. Let me know how it goes.