Confusing issue adding and removing SKPhysicsJointPin upon touch

Question

I'm having trouble with adding and removing my SKPhysicsJointPin in the touchesBegan function. The issue is that my joint is declared in the didMoveToView function because it needs to be positioned based on expressions that exists within it.

That being so I can't refer to the SKPhysicsJoint within the touchesBegan function, which is necessary for what I'm trying to do with my project. Any solutions or suggestions?

Code:

import SpriteKit

class GameScene: SKScene, SKPhysicsContactDelegate {

    var head = SKSpriteNode(imageNamed: "crown.png")
    var headTexture = SKTexture(imageNamed: "crown.png")

    var neck = SKSpriteNode(imageNamed: "throat.png")
    var neckTexture = SKTexture(imageNamed: "throat.png")

    override func didMoveToView(view: SKView) {

        head.position.x = torso.position.x - 1
        head.position.y = torso.position.y + 77
        head.physicsBody = SKPhysicsBody(texture: headTexture, size: head.size)
        head.physicsBody!.categoryBitMask = ColliderType.part.rawValue
        head.physicsBody!.contactTestBitMask = ColliderType.part.rawValue
        head.physicsBody!.collisionBitMask = ColliderType.part.rawValue
        self.addChild(head)

        neck.position.x = torso.position.x
        neck.position.y = torso.position.y + 44
        neck.physicsBody = SKPhysicsBody(texture: neckTexture, size: neck.size)
        neck.physicsBody!.categoryBitMask = ColliderType.mjoint.rawValue
        neck.physicsBody!.contactTestBitMask = ColliderType.mjoint.rawValue
        neck.physicsBody!.collisionBitMask = ColliderType.mjoint.rawValue
        self.addChild(neck)

        let headToNeck = SKPhysicsJointPin.jointWithBodyA(head.physicsBody!, bodyB:neck.physicsBody!, anchor:CGPointMake(head.position.x, head.position.y - 20.8))
        headToNeck.shouldEnableLimits = true
        self.physicsWorld.addJoint(headToNeck)
    }

    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {

        self.physicsWorld.removeJoint(headToNeck)

    }
}

You can remove the joint in `touchesBegan` with `if let joint = head.physicsBody?.joints.first { self.physicsWorld.removeJoint(joint) }` — 0x141E, Jul 07 '16 at 08:02

score 0 · Answer 1 · answered Jul 07 '16 at 12:34

Try creating a class variable like this:

    class GameScene: SKScene, SKPhysicsContactDelegate {   

        var headToNeck: SKPhysicsJoint!
        //other variables

        override func didMoveToView(view: SKView) {
            //other code
            self.headToNeck = SKPhysicsJointPin.jointWithBodyA(head.physicsBody!, bodyB:neck.physicsBody!, anchor:CGPointMake(head.position.x, head.position.y - 20.8))
            self.headToNeck.shouldEnableLimits = true
            self.physicsWorld.addJoint(self.headToNeck)
        }

         override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
            self.physicsWorld.removeJoint(self.headToNeck)
         }
    }

I found the solution yesterday actually it was very similar to this answer, thanks for the help! — Maxwell Kleinsasser, Jul 07 '16 at 16:29

Confusing issue adding and removing SKPhysicsJointPin upon touch

1 Answers1