How to detect a contact in SpriteKit - swift

Question

I'm trying to have a contact to be detected by SpriteKit in Swift 4. I set a flipper to a certain category and a ball to another one. Then I set their collision and contact mask to each other, I add a contactDelegate in didMove to, and print "contact" to inform that there is a contact in a didEnterFonction. However I cannot detect any contact at all. Even after following all the tutorials, and scouring through similar questions. I do not understand what I am doing wrong. My end goal is to have the ball stop from falling when it hits the flipper, but I am trying to detect any contact at all in the first place which do not work.
import SpriteKit
import GameplayKit
struct PhysicsCategory {
static let none : UInt32 = 0
static let all : UInt32 = UInt32.max
static let flip : UInt32 = 0b1
static let ball: UInt32 = 0b10 // 2
}
class GameScene: SKScene, SKPhysicsContactDelegate {
var entities = [GKEntity]()
var graphs = [String : GKGraph]()
private var lastUpdateTime : TimeInterval = 0
private var label : SKLabelNode?
private var flip1: SKSpriteNode?
private var flip2: SKSpriteNode?
private var spinnyNode : SKShapeNode?
private var balle:SKSpriteNode?
override func sceneDidLoad() {
self.lastUpdateTime = 0
self.flip1 = self.childNode(withName:"//flip1") as? SKSpriteNode
self.flip2 = self.childNode(withName: "//flip2") as? SKSpriteNode
self.balle = self.childNode(withName: "//ball") as?SKSpriteNode
self.flip1?.physicsBody = SKPhysicsBody()
self.flip1?.physicsBody?.affectedByGravity = false
self.flip1?.physicsBody?.allowsRotation = true
self.balle?.physicsBody = SKPhysicsBody();
//self.balle?.physicsBody?.affectedByGravity = true
self.flip2?.physicsBody = SKPhysicsBody()
self.flip2?.physicsBody?.affectedByGravity = false
self.flip2?.physicsBody?.allowsRotation = true
self.balle?.physicsBody?.allContactedBodies()
self.flip1?.physicsBody?.usesPreciseCollisionDetection
= true
self.flip1?.physicsBody?.categoryBitMask = PhysicsCategory.flip
self.flip1?.physicsBody?.contactTestBitMask = PhysicsCategory.ball
self.flip1?.physicsBody?.collisionBitMask = PhysicsCategory.ball
self.flip2?.physicsBody?.categoryBitMask = PhysicsCategory.flip
self.flip2?.physicsBody?.contactTestBitMask = PhysicsCategory.ball
self.flip2?.physicsBody?.collisionBitMask = PhysicsCategory.ball
// Get label node from scene and store it for use later
self.label = self.childNode(withName: "//helloLabel") as? SKLabelNode
if let label = self.label {
label.alpha = 0.0
label.run(SKAction.fadeIn(withDuration: 2.0))
}
// Create shape node to use during mouse interaction
let w = (self.size.width + self.size.height) * 0.05
self.spinnyNode = SKShapeNode.init(rectOf: CGSize.init(width: w, height: w), cornerRadius: w * 0.3)
if let spinnyNode = self.spinnyNode {
spinnyNode.lineWidth = 2.5
spinnyNode.run(SKAction.repeatForever(SKAction.rotate(byAngle: CGFloat(Double.pi), duration: 1)))
spinnyNode.run(SKAction.sequence([SKAction.wait(forDuration: 0.5),
SKAction.fadeOut(withDuration: 0.5),
SKAction.removeFromParent()]))
}
}
override func keyDown(with event: NSEvent) {
switch event.keyCode {
case 0x31:
if let label = self.label {
label.run(SKAction.init(named: "Pulse")!, withKey: "fadeInOut")
}
case 123:
print("left")
self.flip1?.run(SKAction.rotate(byAngle: -1.5, duration: 0.2))
// self.flip1?.physicsBody?.applyAngularImpulse(600)
self.flip1?.run(SKAction.rotate(byAngle: 1.5, duration: 0.1))
case 124:
self.flip2?.run(SKAction.rotate(byAngle: 1.5, duration: 0.2))
self.flip2?.run(SKAction.rotate(byAngle: -1.5, duration: 0.1))
case 15:
self.balle?.run(SKAction.move(to: CGPoint(x: 50,y: 50), duration: 1))
default:
print("keyDown: \(event.characters!) keyCode: \(event.keyCode)")
}
}
override func update(_ currentTime: TimeInterval) {
// Called before each frame is rendered
// Initialize _lastUpdateTime if it has not already been
if (self.lastUpdateTime == 0) {
self.lastUpdateTime = currentTime
}
// Calculate time since last update
let dt = currentTime - self.lastUpdateTime
// Update entities
for entity in self.entities {
entity.update(deltaTime: dt)
}
self.lastUpdateTime = currentTime
}
override func didMove(to view: SKView) {
physicsWorld.contactDelegate = self
}
func didEnter(_ contact: SKPhysicsContact) {
print("contact")
}
}

Answer 1

You haven't given the physic bodies a shape or size. Take a look here and read the 'Creating a Body from a ___' sections.