How to make speed of sprite same? - swift

Question

I started writing a simple game to improve my SpriteKit skills in the Xcode using swift language.
In my game there is just one sprite which change it position on place where I clicked on screen.
I did it like this:
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
for touch in touches {
let location = touch.location(in: self)
ZombieNode.run (SKAction.move(to: CGPoint(x: location.x, y: location.y), duration: 1))
}
}
But there is just one problem, the velocity of my sprite depends on where I clicked. So I understand why - because sprite should change location in one second so if i click far from my sprite the speed will be faster, if i click near to sprite the speed is very low. So my question is - How to do speed same? Maybe I should use other function instead of
ZombieNode.run (SKAction.move(to: CGPoint(x: location.x, y: location.y), duration: 1))
or maybe there are some math formulas to do this. So help me please, how can I make speed same everywhere?

Answer 1

You would need to do a distance check first, then multiply your duration by a distance factor.
Using the pythagorean theorem of x2 + y2 = distance2
let deltaX = location.x - current.x
let deltaY = location.y - current.y
let distance = (deltaX * deltaX + deltaY * deltaY).squareRoot()
Then you can get a ratio, using the distance you'd like to travel in a second. For example, if you'd like to move at 400 pixels per second you could do the following:
let pixelsPerSecond = 400
let timeToTravel = distance/pixelsPerSecond
Then use the time to travel here:
ZombieNode.run (SKAction.move(to: CGPoint(x: location.x, y: location.y), duration: timeToTravel))