ios - Sprite-Kit 类别位掩码对于 Physics body 是错误的

Question

这真让我恼火，我有一个播放器和一个场景，还有碰撞检测。当我进入 didBeginContact 时，if 条件返回 false。

我停下来调试，secondbody(在这种情况下应该是场景)有一个随机数的 categoryBitMask，不是我从中分配的那个PhysicsCategory 结构，所以它不会进入 if 条件。是因为场景是 edgeLoopF​​romRect 吗？

代码如下:

struct PhysicsCategory {
    static let None      : UInt32 = 0
    static let Player    : UInt32 = 0b1
    static let Scene     : UInt32 = 0b10
    static let All       : UInt32 = UInt32.max
}
class GameScene: SKScene, SKPhysicsContactDelegate {
    var canJump = true
    var touchStart = CGPoint()
    var touchEnd = CGPoint()
    var squaresArray = NSMutableArray()
    var player = SKSpriteNode(imageNamed: "craft.png")
    override func didMoveToView(view: SKView) {
        physicsWorld.contactDelegate = self
        physicsBody?.categoryBitMask = PhysicsCategory.Scene
        physicsBody?.contactTestBitMask = PhysicsCategory.Player
        physicsWorld.gravity = CGVectorMake(0, -2)
        physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
        physicsBody?.usesPreciseCollisionDetection = true
        setUpPlayer()
    }
    func setUpPlayer() {
        player.physicsBody = SKPhysicsBody(rectangleOfSize: player.size)
        player.physicsBody?.categoryBitMask = PhysicsCategory.Player
        player.physicsBody?.contactTestBitMask = PhysicsCategory.All
        player.physicsBody?.mass = 1
        player.physicsBody?.restitution = 0
        player.xScale = 0.5
        player.yScale = 0.5
        player.position = CGPoint(x: 600, y: 700)
        addChild(player)
    }

    func didBeginContact(contact: SKPhysicsContact) {
        var firstBody: SKPhysicsBody?
        var secondBody: SKPhysicsBody?
        if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
            firstBody = contact.bodyA
            secondBody = contact.bodyB
        } else {
            firstBody = contact.bodyB
            secondBody = contact.bodyA
        }
        if (firstBody!.node != nil && secondBody!.node != nil) {
            println("not nil")
            if ((firstBody!.categoryBitMask == PhysicsCategory.Player) &&
                (secondBody!.categoryBitMask == PhysicsCategory.Scene)) {
                    println("collision")
                    canJump = true   
            }
        }
    }

Answer 1

我可以等一下吗...

WTTTTFFFFFFF

现在我明白了，问题是我在设置 categoryBitMask 之后声明了 physicsBody。所以切换这个:

override func didMoveToView(view: SKView) {
    physicsWorld.contactDelegate = self
    physicsBody?.categoryBitMask = PhysicsCategory.Scene
    physicsBody?.contactTestBitMask = PhysicsCategory.Player
    physicsWorld.gravity = CGVectorMake(0, -2)
    physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)//this line moves up
    physicsBody?.usesPreciseCollisionDetection = true
    setUpPlayer()
}

为此:

override func didMoveToView(view: SKView) {
    physicsWorld.contactDelegate = self
    physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)//to here
    physicsBody?.categoryBitMask = PhysicsCategory.Scene
    physicsBody?.contactTestBitMask = PhysicsCategory.Player
    physicsWorld.gravity = CGVectorMake(0, -2)
    physicsBody?.usesPreciseCollisionDetection = true
    setUpPlayer()
}

解决了这个问题...