How to detect precisely when a SKShapeNode is touched? - ios

Question

I'm working with Swift and SpriteKit.
I have the following situation :
Here, each of the "triangles" is a SKShapenode.
My problem is that I would like to detect when someone touches the screen which triangle is being touched.
I assume that the hitbox of all these triangles are rectangles so my function returns me all the hitboxes touched while I only want to know which one is actually touched.
Is there any way to have a hitbox that perfectly match the shape instead of a rectangle ?
Here's my current code :
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?)
{
let touch = touches.first
let touchPosition = touch!.locationInNode(self)
let touchedNodes = self.nodesAtPoint(touchPosition)
print(touchedNodes) //this should return only one "triangle" named node
for touchedNode in touchedNodes
{
if let name = touchedNode.name
{
if name == "triangle"
{
let triangle = touchedNode as! SKShapeNode
// stuff here
}
}
}
}

Answer 1

You could try to use CGPathContainsPoint with a SKShapeNode instead of nodesAtPoint, which is more appropriate:
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?)
{
let touch = touches.first
let touchPosition = touch!.locationInNode(self)
self.enumerateChildNodesWithName("triangle") { node, _ in
// do something with node
if node is SKShapeNode {
if let p = (node as! SKShapeNode).path {
if CGPathContainsPoint(p, nil, touchPosition, false) {
print("you have touched triangle: \(node.name)")
let triangle = node as! SKShapeNode
// stuff here
}
}
}
}
}

Answer 2

This would be the easiest way of doing it.
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?)
{
for touch in touches {
let location = touch.locationInNode(self)
if theSpriteNode.containsPoint(location) {
//Do Whatever
}
}
}

Answer 3

The way I do this with Swift 4:
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
guard let touch = touches.first else {
return
}
let touchPosition = touch.location(in: self)
let touchedNodes = nodes(at: touchPosition)
for node in touchedNodes {
if let mynode = node as? SKShapeNode, node.name == "triangle" {
//stuff here
mynode.fillColor = .orange //...
}
}
}