Detect object proximity to walls - swift

Question

I am trying to write something really simple - and use SpriteKit on this instance.
The way I did it on other platforms, is by having an invisible child "stick" sticking out a bit. By detecting collision between the invisible "sticks" I can tell wherether the object is close to the wall or not.
I am trying to replicate the same thing using SpriteKit. Of course, I'd prefer to have an invisible "beam" coming out of the object and giving me distance - but that's probably too much hassle.
I'd appriciate any ways to improve on my silly project I got so far.
My Project so far
Thanks.

Answer 1

Here is what I came up with that doesn't involve physics...
Drag the mouse to move the car, and the label in the center updates telling you the distance to the closest wall. Release mouse to reset car.
Very simple example, can be updated to give more accurate measurements.
class GameScene: SKScene {
let car = SKSpriteNode(color: .blue, size: CGSize(width: 50, height: 100))
let label = SKLabelNode(text: "")
func findNearestWall() -> CGFloat {
// you can make this more advanced by using the CGPoint of the frame borders of the car, or even 6+ points for more accuracy
let closestX: CGFloat = {
if car.position.x < 0 { // left wall
return abs(frame.minX - car.position.x)
} else { // right wall
return abs(frame.maxX - car.position.x)
}
}()
let closestY: CGFloat = {
if car.position.y < 0 { // bottom wall
return abs(frame.minY - car.position.y)
} else { // top wall
return abs(frame.maxY - car.position.y)
}
}()
if closestX < closestY {
return closestX.rounded() // as closest wall distance
} else {
return closestY.rounded() // as closest wall distance
}
}
override func didMove(to view: SKView) {
removeAllChildren()
label.fontSize *= 2
addChild(car)
addChild(label)
}
override func mouseDown(with event: NSEvent) {
}
override func mouseDragged(with event: NSEvent) {
let location = event.location(in: self)
car.position = location
}
override func mouseUp(with event: NSEvent) {
car.position = CGPoint.zero
}
override func didEvaluateActions() {
label.text = String(describing: findNearestWall())
}
}