Get touch location of screen in a spritekit game - ios

Question

i have a sprite kit game and im trying to know if the user has touch the left, right or middle of the screen (25/50/25)
At the moment when i touch the very left side of the screen, it says im touching -450 on the x axis when it should be 0. I assume its getting my touch position relative to the scene and as the achor point starts 450 pixels to the right, gives me -450 when i touch 0.
As this is a side scroller, moving the achor wont work and i need the touch location of the screen:
override func touchesBegan(_ touches: Set<UITouch>,with event: UIEvent?){
var touchLeft : Bool = false
var touchRight : Bool = false
var touchMiddle : Bool = false
for touch in (touches) {
let location = touch.location(in: self)
if(location.x < self.size.width/4){
touchLeft = true
print("Left")
} else if(location.x > ((self.size.width/4) * 3)){
touchRight = true
print("Right")
} else {
touchMiddle = true
print("Middle")
}
}
}

Answer 1

You almost had it, just factor in negative numbers.
In case you were not aware, 0 is the center by default for SKScene. This is because the default anchor point is 0.5,0.5.
Since you are using the camera to handle your scrolling, you want to use
touch.location(in: self.camera) so that you are always touching relative to where the camera is and not where the scene is.
So just change your code to as follows:
override func touchesBegan(_ touches: Set<UITouch>,with event: UIEvent?){
var touchLeft : Bool = false
var touchRight : Bool = false
var touchMiddle : Bool = false
for touch in (touches) {
let location = touch.location(in: self.camera)
if(location.x < -self.size.width/4){
touchLeft = true
print("Left")
} else if(location.x > ((self.size.width/4))){
touchRight = true
print("Right")
} else { //x is between -width / 4 and width / 4
touchMiddle = true
print("Middle")
}
}
}