Detecting when two of the same colors collide - swift

Question

I have a square consisting of four different colors in the middle of my scene. At the same time, I have smaller squares of the same color randomly generated from each sides of the scene with the intention of colliding with the square in the middle. (Blue to blue, yellow to yellow, etc).
My goal is to have it set up so that when a blue square collides with a blue square or any of the like, it will .removeFromParent(). How should I go about doing this? Will post code if necessary.
Edit:
enum BodyType: UInt32 {
case blueSquare = 1
case redSquare = 2
case yellowSquare = 4
case greenSquare = 8
}
let contactMask = contact.bodyA.categoryBitMask | contact.bodyB.categoryBitMask
didBeginContact() {
switch(contactMask) {
case BodyType.redSquare.rawValue | BodyType.redSquare.rawValue:
let scoreLabel = childNodeWithName("scores") as! Points
scoreLabel.increment()
let firstNode = contact.bodyB.node
firstNode?.removeFromParent()
default:
return
}
}

Answer 1

First thing you should do is set up the contactTestBitMasks & categoryBitMasks on all of your SKSpriteNodes, like this -
struct PhysicsCatagory {
static let FirstPerson : UInt32 = 0x1 << 1
static let SecondPerson : UInt32 = 0x1 << 2
}
override func didMoveToView(view: SKView) {
...
firstPerson.SKPhysicsBody?.catagoryBitMask = PhysicsCatagory.FirstPerson
firstPerson.SKPhysicsBody?.contactTestBitMask = PhysicsCatagory.SecondPerson
...
secondPerson.SKPhysicsBody?.catagoryBitMask = PhysicsCatagory.SecondPerson
secondPerson.SKPhysicsBody?.contactTestBitMask = PhysicsCatagory.FirstPerson
...
}
This is just setting up the catagoryBitMask and the contactTestBitMask. The categoryBitMask will be equal to the object you are currently editing, whereas, the contactTestBitMask will be equal to the object you want the object to collide with.
Also, before we move on, we want to add the Contact Delegate to our scene.
class GameScene: SKScene, SKPhysicsContactDelegate{...
And then add the delegate to our scene -
override func didMoveToView(view: SKView) {
...
self.physicsWorld.contactDelegate = self
...
Next, you add the didBeginContact
func didBeginContact(contact: SKPhysicsContact) {
let firstBody = contact.bodyA.node as! SKSpriteNode!
let secondBody = contact.bodyB.node as! SKSpriteNode!
}
Lastly inside of that, test...
func didBeginContact(contact: SKPhysicsContact) {
let firstBody = contact.bodyA.node as! SKSpriteNode!
let secondBody = contact.bodyB.node as! SKSpriteNode!
if firstBody.color == secondBody.color{
firstBody.removeFromParent()
secondBody.removeFromParent()
}
}
Hope that helps! :D

Answer 2

Once you detect a collision, compare the colors of the colliding squares and if equal, call .removeFromParent(). If you post code I could try to give the specific methods that would help.
If you want to get fancy you could create a subclass for your squares with a colorTag property (1 = blue, 2 = yellow ect.) and then compare the tags of the colliding squares. Although I doubt the cost of comparing the colors is much.