skphysicscontact

So I have my "Floor.swift" class below which is basically a bunch of walls. I have objects coming from the top of the screen and once the Floor and SKSpriteNodes collide, I'd like the SKSpriteNode to be removed. Below is my Floor class. import Foundation import SpriteKit class Floor: SKNode { override init() { super.init() let leftWall = SKSpriteNode(color: UIColor.brown, size: CGSize(width: 5, height: 50)) leftWall.position = CGPoint(x: 0, y: 50) leftWall.physicsBody = SKPhysicsBody(rectangleOf: leftWall.size) leftWall.physicsBody!.isDynamic = false self.addChild(leftWall) let rightWall =

I have a helper method which extends SKPhysicsContact extension SKPhysicsContact { /// - returns: `[SKPhysicsBody]` containing all the bodies that match `mask` func bodiesMatchingCategory(mask: UInt32) -> [SKPhysicsBody] { let bodies = [bodyA, bodyB] return bodies.filter { ($0.categoryBitMask & mask) != 0 } } } in didBeginContact() I call this method on the passed in contact . func didBeginContact(contact: SKPhysicsContact) { let ballMask: UInt32 = 0x1 << 2 let ball = contact.bodiesMatchingCategory(ballMask) ... I get this error message sometimes (like 1 in 5) which crashes the app: -

I want a sprite to delete itself when touching another sprite. Right now when they touch, they just push each other. I have this: let alphaCategory: UInt32 = 0x1 << 0 let betaCategory: UInt32 = 0x1 << 1 I made the sprites dynamic and not affected by gravity self.physicsworld.contactDelegate = self alpha.physicsBody?.categoryBitMask = alphaCategory alpha.physicsBody?.contactTestBitmask = betaCategory and beta.physicsBody?.categoryBitMask = betaCategory beta.physicsBody?.contactTestBitmask = alphaCategory I couldn't find anything in swift that made sense to me, but I think the problem is here