两个sk节点相交时的标志

Question

在我的快速代码中，左右按钮下方围绕一个名为“棍”的节点移动。我希望当用户点击使棍子与边界相交的按钮时。调试部分将打印“flag”。我知道 uikit 中有一个 intersect 命令，但我不知道 sprite kit 中有一个。青色是界限

class GameScene: SKScene {
    var stick: SKSpriteNode!
    var leftButton: SKSpriteNode!
    var rightButton: SKSpriteNode!
    var bounds: SKSpriteNode!
    
    override func didMove(to view: SKView) {
        backgroundColor = SKColor.white
        
        // Create and position the stick
        stick = SKSpriteNode(color: .brown, size: CGSize(width: 160, height: 20))
        stick.position = CGPoint(x: size.width * -0.2, y: size.height * -0.1)
        addChild(stick)
        
        
        bounds = SKSpriteNode(color: .systemTeal, size: CGSize(width: 150, height: 300))
        bounds.position = CGPoint(x: size.width * -0.4, y: size.height * -0.2)
        addChild(bounds)
        
        
        // Create left and right buttons
        leftButton = SKSpriteNode(color: .blue, size: CGSize(width: 100, height: 50))
        leftButton.position = CGPoint(x: size.width * 0.2, y: size.height * 0.1)
        addChild(leftButton)
        
        rightButton = SKSpriteNode(color: .red, size: CGSize(width: 100, height: 50))
        rightButton.position = CGPoint(x: size.width * -0.1, y: size.height * 0.1)
        addChild(rightButton)
    }
    
    
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        for touch in touches {
            let location = touch.location(in: self)
            
            if leftButton.contains(location) {
                // Rotate the stick counterclockwise
                let rotateAction = SKAction.rotate(byAngle: CGFloat(Double.pi / 4), duration: 1.0)
                stick.run(rotateAction)
                print("hit Left")
            }
            
            if rightButton.contains(location) {
                // Rotate the stick clockwise
                let rotateAction = SKAction.rotate(byAngle: -CGFloat(Double.pi / 4), duration: 1.0)
                stick.run(rotateAction)
            }
        }
    }

}

我认为在这种情况下相交不是一个选择。

Answer 1

SpriteKit 有一个检测系统，可以告诉您两个节点何时相互接触。您可以通过使类符合

SKPhysicsContactDelegate

来向类添加接触检测回调。

例如。

class ContactDetectionLogic: SKPhysicsContactDelegate { 
    func didBegin(_ contact: SKPhysicsContact) {
        print("flag")
    } 
}

您甚至可以使您自己的

GameScene

符合此协议！ （我通常这样做，而且我认为这是非常典型的做法）

class GameScene: SKScene, SKPhysicsContactDelegate {
    // ...blah blah blah all the other code

    func didBegin(_ contact: SKPhysicsContact) {
        print("flag")
    }
}

一旦决定了哪个对象将接收回调，请确保将此对象分配给

delegate

中的

physicsWorld

属性。

例如：

var objectThatHandlesContactLogic: ContactDetectionLogic!

override func didMove(to view: SKView) {
    objectThatHandlesContactLogic = ContactDetectionLogic()
    physicsWorld.delegate = objectThatHandlesContactLogic
    backgroundColor = SKColor.white
}

或者如果您使场景本身符合委托（这又是更典型的事情），您会这样做：

override func didMove(to view: SKView) {
    physicsWorld.delegate = self  // This is also much cleaner imo
    backgroundColor = SKColor.white
}

添加委托后，您必须配置哪些节点接触会触发它们。在你的情况下，它是棍子和界限，所以你这样做：

override func didMove(to view: SKView) {
    physicsWorld.contactDelegate = self
    physicsWorld.gravity = .zero
    backgroundColor = SKColor.white
        
    // Create and position the stick
    let stickSize = CGSize(width: 60, height: 20)
    stick = SKSpriteNode(color: .brown, size: stickSize)           stick.position = CGPoint(x: size.width * 0.5, y: size.height * 0.5)
    addChild(stick)
        
    // Add physics body to stick
    stick.physicsBody = SKPhysicsBody(rectangleOf: stickSize)
    stick.physicsBody!.categoryBitMask = 0b0000  // Means the stick belongs to no category (all zeros)
    stick.physicsBody!.collisionBitMask = 0b0000  // Means the stick collides with no category (all zeros)
    stick.physicsBody!.contactTestBitMask = 0b0001  // Means the stick will only collide with nodes belonging to category 0001 (in binary, which also happens to mean category "1" in decimal)
    
    // Create and position the bounds box
    let boundsSize = CGSize(width: 150, height: 150)
    bounds = SKSpriteNode(color: .systemTeal, size: boundsSize)
    bounds.position = CGPoint(x: size.width * 0.5, y: size.height * 0.35)
    addChild(bounds)
        
    // add physics body to bounds
    bounds.physicsBody = SKPhysicsBody(rectangleOf: boundsSize)
    bounds.physicsBody!.collisionBitMask = 0b0000  // Means bounds collides with no category (all zeros)
    bounds.physicsBody!.categoryBitMask = 0b0001  // Means the bounds belongs to category 0001 (in binary, which again, translates to "1" in decimal), which if you remember, is what we set the stick to collide with
}

现在，每当联系开始时，您都应该收到一个打印“标记”的信息。