SpriteKit - touchesMoved, aim crosshair - swift

Question

I have a spritenode and a crosshair node, i want when the player touch the spritenode and move the crosshair also moves.
override func touchesMoved(touches: NSSet, withEvent event: UIEvent) {
for touch: AnyObject in touches {
let location = touch.locationInNode(self)
var body = self.nodeAtPoint(location)
if var name: String = body.name {
if body.name == "aim-button" {
crossHair.position = CGPointMake(crossHair.position.x + 10, crossHair.position.y + 10)
}
}
}
}
The crosshair does get move but only in one direction, and i have no idea how to make it accurate depending on the space the touch moved to-from (which is obviously way smaller than what the crosshair should actually move on the screen) and the direction.

Answer 1

for touch: AnyObject in touches {
//Get the current position in scene of the touch.
let location = touch.locationInNode(self)
//Get the previous position in scene of the touch.
let previousLocation = touch.previousLocationInNode(self)
//Calculate the translation.
let translation = CGPointMake(location.x - previousLocation.x, location.y - previousLocation.y)
//Get the current position in scene of the crossHair.
let position = crossHair.position
// Get the bode touched
var body = self.nodeAtPoint(location)
if var name: String = body.name {
if body.name == "aim-button" {
//Set the position of the crosshair to its current position plus the translation.
crossHair.position = CGPointMake(position.x + translation.x * 2, position.y + translation.y * 2)
//Set the position of the body
body.position = location
}
}
}
If the crosshair should move more distance than the touch, just multiply the translation by a factor (i'm using 2 in the example above).