不知道如何将触摸作为单个实体处理

Question

I have a game for iPad where two different players may interact with the environment at the same time. When the game is played by two people in the same device at once I have a problem that I don't know how to solve. I want the game to behave in the next way: when a player touches a sprite, and finishes the touch in another sprite the app must be able to know that it has been the same player who did it.

What my app does now is the following: suppose that player1 touches a sprite. Then, player2 touches another. Neither of them finishes the touch. Now, player1 ends his touch in a third sprite. But, with the code that I have right now, what it would do is to invoke the function "action" with the second and the third sprite, when I need to pass the first and the third sprite, and I'm freaking out a little because I don't know how to do it. Here's the code you need:

var globalReference: Int = 0

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    let touch: UITouch! = touches.first as UITouch!
    let touchLocation = touch.locationInNode(self)
    var spriteTouched: Int? = 0

    if self.nodeAtPoint(touchLocation).name != nil {
        spriteTouched = Int(self.nodeAtPoint(touchLocation).name!)
        globalReference = spriteTouched
    }
}

override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
    let touch: UITouch! = touches.first as UITouch!
    let touchLocation = touch.locationInNode(self)
    var spriteTouched: Int? = 0
    if self.nodeAtPoint(touchLocation).name != nil {
         spriteTouched = Int(self.nodeAtPoint(touchLocation).name!){
         if(globalReference != spriteTouched) {
            action1(globalReference, spriteTouched)
         } else {
             action2(globalReference)
            }
        }
    }
}

The way I get to know what sprite is touched is using ".name" where the name is always an Int. I use the variable globalReference to know what sprite was touched in touchesBegan in touchesEnded, and well, this implementation is what I really don't know how to solve. Consider the rare cases like when you don't touch a sprite solved. I would be grateful if someone could help me a little on this…

Thank you!

PS: Yes, I know it is a difficult question… Just a challenge : )

Answer 1

UITouch objects are persistent. Keep a reference to the name of the sprite found in touchesBegan with the touch.

class property:

var touchesToSprites = [UITouch:Int]()

in touchesBegan:

touchesToSprites[touch] = spriteTouched

in touchesEnded:

action1( touchesToSprites[touch], spriteTouched )
// remove touchesToSprites[touch] when done