I am building a ship game using swift. Unable to detect collisions - ios

Question

I am building a ship game using swift. The objective is to avoid the incoming stones and score as many points as you can as the level increases. The stones come in opposite direction to hit the ship.But I am unable to detect collisions between ship and stone, stone passes through the ship.The ship can move to the left or to the right.
I used rect1.interects(rect2) for intersection.
Thank You.
here is ViewController.swift
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var moveWater: MovingWater!
var boat:UIImageView!
var stone:UIImageView!
var boatLeftRight : UILongPressGestureRecognizer!
var tapTimer:Timer!
var leftM:UInt32 = 55
var rightM:UInt32 = 250
var leftS:UInt32 = 35
var rightS:UInt32 = 220
func startGame() {
boat = UIImageView(image: UIImage(named: "boat"))
boat.frame = CGRect(x: 0, y: 0, width: 60, height: 90)
boat.frame.origin.y = self.view.bounds.height - boat.frame.size.height - 10
boat.center.x = self.view.bounds.midX
self.view.insertSubview(boat, aboveSubview: moveWater)
boatLeftRight = UILongPressGestureRecognizer(target: self, action: #selector(ViewController.leftRight(tap:)))
boatLeftRight.minimumPressDuration = 0.001
moveWater.addGestureRecognizer(boatLeftRight)
}
func leftRight(tap:UILongPressGestureRecognizer) {
if tap.state == UIGestureRecognizerState.ended {
if (tapTimer != nil) {
self.tapTimer.invalidate()
}
} else if tap.state == UIGestureRecognizerState.began {
let touch = tap.location(in: moveWater)
if touch.x > moveWater.frame.midX {
tapTimer = Timer.scheduledTimer(timeInterval: TimeInterval(0.005), target: self, selector: #selector(ViewController.moveBoat(time:)), userInfo: "right", repeats: true)
} else {
tapTimer = Timer.scheduledTimer(timeInterval: TimeInterval(0.005), target: self, selector: #selector(ViewController.moveBoat(time:)), userInfo: "left", repeats: true)
}
}
}
func moveBoat(time:Timer) {
if let d = time.userInfo as? String! {
var bot2 = boat.frame
if d == "right" {
if bot2.origin.x < CGFloat(rightM) {
bot2.origin.x += 2
}
} else {
if bot2.origin.x > CGFloat(leftM) {
bot2.origin.x -= 2
}
}
boat.frame = bot2
}
}
func movingStone() {
stone = UIImageView(image: UIImage(named: "stones.png"))
var stone2 = leftS + arc4random() % rightS
stone.bounds = CGRect(x:10, y:10, width:81.0, height:124.0)
stone.contentMode = .center;
stone.layer.position = CGPoint(x: Int(stone2), y: 10)
stone.transform = CGAffineTransform(rotationAngle: 3.142)
self.view.insertSubview(stone, aboveSubview: moveWater)
UIView.animate(withDuration: 5, delay: 0, options: UIViewAnimationOptions.curveLinear, animations: { () -> Void in
self.stone.frame.origin.y = self.view.bounds.height + self.stone.frame.height + 10
}) { (success:Bool) -> Void in
self.stone.removeFromSuperview()
self.movingStone()
}
}
func update() {
if(boat.bounds.intersects(stone.bounds)) {
boat.image = //set new image
}
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
moveWater.backgroundStart()
startGame()
movingStone()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}

Answer 1

I saw your own answer. This is basic collision detection indeed. You should still have a look at SpriteKit. I see that you are using a Timer, which is not the best way to go since Timers will give you performance issues in the long run. It's a common mistake when you start game developement.
Maybe you think that you can ensure a frame rate by setting a very fast timer. The thing is that timers are not consistent and they have low priority too. This means that your timer call will be delayed if something more important happens in the background. If your movement is based on that forced refresh rate, it will become choppy very quickly. Also the code you run in the timer might get faster or slower depending on the logic you are using.
SpriteKit provides you with an update function that is run every frame and that let's you know about the current system time at every frame. By keeping track of that value, you can then calculate how much time went between two frames and you can then scale your movement accordingly to compensate for the time difference between two frames.
On top of that SpriteKit offers you a bunch of options for collision detection and movement. It integrates a very well made Physics Engine and collision detection system. It will also do collision detection on complex shapes, apply forces to the bodies, etc.
I strongly suggest you follow the link to Ray Wenderlich's website given to you in the answer above. If you have the budget, you might also want to buy their book on how to make 2D games for Apple devices. I've read that cover to cover and I can say I love it. I can now do my own stuff with SpriteKit and it's also a very good starter for newcomers to swift.

Answer 2

Any reason you choose UIKit to make your game?
If you make a game you should really be using SpriteKit instead of UIKit.
Check google and youtube for SpriteKit tutorials, there is loads.
A really good start is this one that teaches you the basics of the SpriteKit Scene editor and how to do collisions etc.
https://www.raywenderlich.com/118225/introduction-sprite-kit-scene-editor
I recommend that you do not continue like this.
Hope this helps

Answer 3

I fixed this myself. It was easy and without any SpriteKit, I have detected collisions.
func intersectsAt(tap2 : Timer) {
var f1 : CGRect!
var f2 : CGRect!
f1 = boat.layer.presentation()?.frame
f2 = stone.layer.presentation()?.frame
if(f1.intersects(f2)) {
stopGame()
}
}