Detect intersect with masked image (not rectangular) - swift

Question

How to not get detected with intersects func when moving around masked image in UIImageView frame?
explanation image
Code that I am using to detect collision:
movingPerson.frame.intersects(camera.frame)
Where movingPerson is just a regular UIImage that I am moving around with touchesmoved func and camera is a masked Image.
I've tried .bounds instead of .frame but it's not working.
Is there any easy way?

Answer 1

If you want the "Very easy way" then UIDynamicItem and provide a path that bounds your image and let UIDynamicAnimator handle the collisions for you. If you do not know how to get the path for your artwork (yours is pretty easy and you should be able to extract the Bezier coordinates automatically in Paintcode, by hand in Illustrator, or from a SVG file) you can use SpriteKit instead since it will actually generate the bounding polygon for your sprite automatically.
EDIT Sample (note I didn't want to write a whole app for this so I took an existing playground and just added the colliders. the collision works, but the reset after collision doesn't):
import UIKit
import PlaygroundSupport
class ObstacleView: UIView {
override var collisionBoundsType: UIDynamicItemCollisionBoundsType {
return .path
}
override var collisionBoundingPath: UIBezierPath {
return UIBezierPath(ovalIn: bounds)
}
override func layoutSubviews() {
super.layoutSubviews()
layer.cornerRadius = bounds.size.width / 2
}
}
class ViewController: UIViewController {
var dynamicAnimator: UIDynamicAnimator!
var gravityBehavior: UIGravityBehavior!
var pushBehavior: UIPushBehavior!
var collisionBehavior: UICollisionBehavior!
lazy var player: UILabel = {
let label = UILabel()
label.text = "🐥"
label.sizeToFit()
label.isUserInteractionEnabled = true
label.translatesAutoresizingMaskIntoConstraints = false
self.view.addSubview(label)
return label
}()
var isPanning = false
var anchor: CGPoint = .zero
let maxDistance = CGFloat(100)
lazy var obstacles: [UIView] = {
return (0..<2).map { index in
let view = ObstacleView(frame: CGRect(x:100 + CGFloat(index)*200,y:200, width: 40, height: 40))
view.backgroundColor = .blue
view.translatesAutoresizingMaskIntoConstraints = false
self.view.addSubview(view)
return view
}
}()
override func viewDidLoad() {
super.viewDidLoad()
dynamicAnimator = UIDynamicAnimator(referenceView: view)
dynamicAnimator.delegate = self
gravityBehavior = UIGravityBehavior(items: [player])
let panGestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(pan))
_ = obstacles
view.addGestureRecognizer(panGestureRecognizer)
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
anchor = view.center
player.center = anchor
}
#objc private func pan(recognizer: UIPanGestureRecognizer) {
switch recognizer.state {
case .began:
guard player.bounds.contains(recognizer.location(in: player)) else {
isPanning = false
return
}
isPanning = true
case .changed:
guard isPanning else {
return
}
player.center = recognizer.location(in: view)
let dx = player.center.x - anchor.x
let dy = player.center.y - anchor.y
let distance = CGFloat(hypotf(Float(dx), Float(dy)))
if distance > maxDistance {
player.center.x = anchor.x + dx / distance * maxDistance
player.center.y = anchor.y + dy / distance * maxDistance
}
case .ended:
guard isPanning else {
return
}
isPanning = false
let dx = player.center.x - anchor.x
let dy = player.center.y - anchor.y
let distance = CGFloat(hypotf(Float(dx), Float(dy)))
guard distance > 10 else {
player.center = anchor
return
}
if pushBehavior != nil {
dynamicAnimator.removeBehavior(pushBehavior)
}
pushBehavior = UIPushBehavior(items: [player], mode: .instantaneous)
pushBehavior.pushDirection = CGVector(dx: -dx, dy: -dy)
pushBehavior.magnitude = distance / maxDistance * 0.75
dynamicAnimator.addBehavior(pushBehavior)
dynamicAnimator.addBehavior(gravityBehavior)
collisionBehavior = UICollisionBehavior(items: [player] + obstacles)
collisionBehavior.translatesReferenceBoundsIntoBoundary = true
collisionBehavior.collisionDelegate = self
dynamicAnimator.addBehavior(collisionBehavior)
case .cancelled:
isPanning = false
player.center = anchor
default:
break
}
}
}
extension ViewController: UIDynamicAnimatorDelegate {
func dynamicAnimatorDidPause(_ animator: UIDynamicAnimator) {
dynamicAnimator.removeAllBehaviors()
player.center = anchor
}
}
extension ViewController: UICollisionBehaviorDelegate {
func collisionBehavior(_ behavior: UICollisionBehavior, beganContactFor item1: UIDynamicItem, with item2: UIDynamicItem, at p: CGPoint) {
print("contact")
}
}
PlaygroundPage.current.liveView = ViewController()
PlaygroundPage.current.needsIndefiniteExecution = true