Can't subtract two CGPoint operands in Swift 3 error

Question

I’m developing a game in Swift 3 with SpriteKit.

I’m having some problems with the conditional below.

if (personaje.position - lastTouchLocation).length() < pjPixelsPerSecond * CGFloat(dt){
    velocity = CGPoint.zero
} else {
  moveSprite(sprite: personaje, velocity: velocity)
}

I get the following error:

Binary operator '-' cannot be applied to two 'CGPoint' operands.

How can I subtract these two variables?

And I got:

var personaje = SKSpriteNode(imageNamed: "personajee")
var velocity = CGPoint.zero
var lastTouchLocation = CGPoint.zero
… 

func sceneTouched (touchLocation: CGPoint) {
    lastTouchLocation = touchLocation
    movePjToLocation(location: touchLocation)

}

Answer 1

You have to define by yourself the - operator for CGPoint. Declare the function outside of any class's scope, so it will be visible in your whole project.

// Declare `-` operator overload function
func -(lhs: CGPoint, rhs: CGPoint) -> CGPoint { 
    return CGPoint(x: lhs.x - rhs.x, y: lhs.y - rhs.y)
}
// TEST
let point1 = CGPoint(x: 10, y: 10)
let point2 = CGPoint(x: 5, y: 5)
print(point1 - point2) //prints (5.0, 5.0)