SpriteKit & Swift 3 - Bounce Not Working Properly With Ball Node - swift

Question

I made a game which essentially has a ball and a couple of targets and paddles. However I needed to make it so depending on what target the ball collides with the speed is either tripled, doubled or halved as long as it doesn't drop below a minimum speed or goes above a maximum speed.
To do this I used the didBegin(contact) function together and set the different velocities as it can be seen in the code below:
extension CGVector {
var speed: CGFloat {
return hypot(dx, dy)
}
static func > (lhs: CGVector, rhs: CGVector) -> Bool {
return lhs.speed > rhs.speed
}
static func < (lhs: CGVector, rhs: CGVector) -> Bool {
return lhs.speed < rhs.speed
}
static func * (vector: CGVector, multiplier: CGFloat) -> CGVector {
return CGVector(dx: vector.dx * multiplier, dy: vector.dy * multiplier)
}
static func / (vector:CGVector, divider:CGFloat) -> CGVector {
return CGVector(dx: vector.dx / divider, dy: vector.dy / divider)
}
}
func didBegin(_ contact: SKPhysicsContact) {
var firstBody = SKPhysicsBody()
var secondBody = SKPhysicsBody()
let ballNode = self.childNode(withName: ballName)
let minSpeed = self.initialSpeed / 2
let maxSpeed = self.initialSpeed * 3
if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
firstBody = contact.bodyA
secondBody = contact.bodyB
} else {
firstBody = contact.bodyB
secondBody = contact.bodyA
}
if firstBody.categoryBitMask == ballBitmask && secondBody.categoryBitMask == drainBitmask {
endGame()
Timer.scheduledTimer(timeInterval: 3, target: self, selector: #selector(GameScene.showLeaderboard), userInfo: nil, repeats: false)
} else if firstBody.categoryBitMask == ballBitmask && secondBody.categoryBitMask == target1Bitmask {
let currentSpeed = ballNode?.physicsBody?.velocity
score += 20
self.vc.scoreLabel.text = "Score: \(score)"
if currentSpeed == maxSpeed {
ballNode?.physicsBody?.velocity = currentSpeed!
} else if (currentSpeed! * 2) > maxSpeed {
ballNode?.physicsBody?.velocity = maxSpeed
} else if (currentSpeed! * 2) < maxSpeed {
ballNode?.physicsBody?.velocity = currentSpeed! * 2
}
} else if firstBody.categoryBitMask == ballBitmask && secondBody.categoryBitMask == target2Bitmask {
let currentSpeed = ballNode?.physicsBody?.velocity
score += 10
self.vc.scoreLabel.text = "Score: \(score)"
if currentSpeed == minSpeed {
ballNode?.physicsBody?.velocity = currentSpeed!
} else if (currentSpeed! / 2) > minSpeed {
ballNode?.physicsBody?.velocity = currentSpeed! / 2
} else if (currentSpeed! / 2) < minSpeed {
ballNode?.physicsBody?.velocity = minSpeed
}
} else if firstBody.categoryBitMask == ballBitmask && secondBody.categoryBitMask == target3Bitmask {
let currentSpeed = ballNode?.physicsBody?.velocity
score += 30
self.vc.scoreLabel.text = "Score: \(score)"
if currentSpeed == maxSpeed {
ballNode?.physicsBody?.velocity = currentSpeed!
} else if (currentSpeed! * 3) > maxSpeed {
ballNode?.physicsBody?.velocity = maxSpeed
} else if (currentSpeed! * 3) < maxSpeed {
ballNode?.physicsBody?.velocity = currentSpeed! * 3
}
}
My issue is sometimes when the ball collides with the targets it bounces off in a very weird and unrealistic way and sometimes just essentially glitches out (please check the link below for a short video clip which shows what I mean)
Note: At 2/3 seconds into the video is an example of the weird bounce happening
https://drive.google.com/open?id=0BxgQmn_JruJ_aUU2dVBoVlprV0k
Why is this happening and more importantly how can I fix it?
PS: One suggestion that I believe might be causing this is the fact the vector for velocity controls both the angle(direction) and speed (I think)of the ball therefore when I set the velocity the direction isn't taken in account. If this is the cause would it be possible to triple/double/halve the velocity whilst still making the bounce realistic?