展开可选值:PhysicsBody-Swift SpriteKit [英] Unwrapping optional values: PhysicsBody - Swift SpriteKit

问题描述

所以我在游戏中对球进行了一些调整，为避免出现可选值错误，我对以下内容进行了表扬

So I made some adjustments to the ball in my game and to avoid an unwrapping optional value error, I commmented out the following

//didMoveToView
    self.physicsWorld.gravity = CGVectorMake(0, 0)
    self.physicsWorld.contactDelegate = self
    let fieldBody = SKPhysicsBody.init(edgeLoopFromRect: self.frame)
    self.physicsBody = fieldBody
    self.physicsBody!.affectedByGravity = false
    self.physicsBody!.usesPreciseCollisionDetection = true
    self.physicsBody!.dynamic = true
    self.physicsBody!.mass = 0
    self.physicsBody!.friction = 0
    self.physicsBody!.linearDamping = 0
    self.physicsBody!.angularDamping = 0
    self.physicsBody!.restitution = 1
    self.physicsBody!.categoryBitMask = CollisionTypes.Floor.rawValue
    self.physicsBody!.contactTestBitMask = CollisionTypes.Ball.rawValue

    // Prepare the ball - physics engine.
    ball.physicsBody = SKPhysicsBody(circleOfRadius: ball.frame.width/2)
    ball.physicsBody!.affectedByGravity = true
    ball.physicsBody!.restitution = 0.8
    ball.physicsBody!.linearDamping = 0
    ball.physicsBody!.friction = 0.3
    ball.physicsBody!.dynamic = true
    ball.physicsBody!.mass = 0.5
    ball.physicsBody!.allowsRotation = true
    ball.physicsBody!.categoryBitMask = CollisionTypes.Ball.rawValue
    ball.physicsBody!.contactTestBitMask = CollisionTypes.Floor.rawValue
    ball.physicsBody!.collisionBitMask = CollisionTypes.Floor.rawValue
}

我做到了，我的游戏开始了，但是toucheBegan出现了同样的错误.我不知道如何解决所有这些无法解决的错误.我是新手，不知道如何调整这些物理学.我的contactBegin看起来像这样:

I did that, my game launced but as soon as toucheBegan, the same error popped up. I do not know how to get around all of these unrwapping errors. I am new to swift and not sure how i should adjust thse physics. My contactBegin looks this:

func didBeginContact(contact: SKPhysicsContact) {
    let bitMaskAAndB = contact.bodyA.categoryBitMask == CollisionTypes.Floor.rawValue &&
                contact.bodyB.categoryBitMask == CollisionTypes.Ball.rawValue
    let ballAndBoardMask = CollideType.Ball.toMask() | boards.usedCollideMasks

    // ball and board, handle it by board delegate
    if bitMaskAAndB | ballAndBoardMask == ballAndBoardMask {

        let boardNode: SKNode! = contact.bodyA.categoryBitMask == CollideType.Ball.toMask() ? contact.bodyB.node : contact.bodyA.node
        let board = boardNode.bind as! BoardDelegate
        board.didBeginContact(boardNode, ball: ball, contact: contact, game: self)
    }

    // ball and ceil => stop game
    else if bitMaskAAndB == CollideType.toMask([.Ball, .Ceil]) {
        stopGame()
    }

    // ball and floor => stop game add explosion or fall off screen
    else if bitMaskAAndB == CollideType.toMask([.Ball, .Floor]) {
        stopGame()
    }
}
func didEndContact(contact: SKPhysicsContact) {

    let ballAndBoardMask = CollideType.Ball.toMask() | boards.usedCollideMasks

    // ball and board, handle it by board delegate
    if contact.bodyA.categoryBitMask | contact.bodyB.categoryBitMask | ballAndBoardMask == ballAndBoardMask {

        let boardNode: SKNode! = contact.bodyA.categoryBitMask == CollideType.Ball.toMask() ? contact.bodyB.node : contact.bodyA.node
        let board = boardNode.bind as! BoardDelegate
        board.didEndContact(boardNode, ball: ball, contact: contact, game: self)
    }

}

我根据您的建议设置了物理世界，并调整了didBeginContact的乐趣，但是，使用以下代码，我遇到了多个错误:无法将bool类型的值转换为UInt32.

I set up my physics world to the suggestions you made and adjusted my didBeginContact fun however with the following code, I am getting multiple errors regarding: cannot convert value of type bool to UInt32.

PS.感谢您的帮助和耐心等待，这是所有新术语，我将尽我所能来理解. :)

PS. thank you for your help and patience, this is all new terminology and Im doing my best to understand. :)

推荐答案

我不知道您的CollideType类或声明，因此下面的代码向您解释了如何构建正确的physicsWorld和physicsBody来在碰撞过程中没有问题.

I don't know your CollideType class or declaration, so my code below explain to you how to build a correct physicsWorld and physicsBody to don't have issues during the collisions.

但是首先:我们将在此项目中最大程度地使用 categoryBitMask ， contactTestBitMask 和 collisionBitMask 属性，因为我们具有使项目正常运行的非常精确的规则:

But first: we're going to be using the categoryBitMask, contactTestBitMask and collisionBitMask properties in their fullest for this project, because we have very precise rules that make the project work:

• categoryBitMask 是一个数字，用于定义此对象的类型 考虑碰撞.

• categoryBitMask is a number defining the type of object this is for considering collisions.

collisionBitMask 是一个数字，用于定义此对象的类别 节点应该碰撞.

collisionBitMask is a number defining what categories of object this node should collide with.

contactTestBitMask 是一个数字，用于定义我们要发生的碰撞 被通知.

contactTestBitMask is a number defining which collisions we want to be notified about.

SpriteKit期望使用UInt32描述这三个位掩码.您的位掩码应从1开始，然后每次加倍.

SpriteKit expects these three bitmasks to be described using a UInt32.Your bitmasks should start at 1 then double each time.

代码:

class GameScene: SKScene, SKPhysicsContactDelegate {
    var ball: Ball!
    let ballSpeedX = CGFloat(500)
    enum CollisionTypes: UInt32 {
        case Field = 1
        case Ball = 2
    }
    override func didMoveToView(view: SKView) {
        // ball
        ball = Ball(imageNamed:"colorBall.png")
        ball.position = CGPointMake(self.ball.frame.size.width,self.ball.frame.size.height)

        // Prepare the world - physics engine.
        self.physicsWorld.gravity = CGVectorMake(0, -6)
        self.physicsWorld.contactDelegate = self
        let fieldBody = SKPhysicsBody.init(edgeLoopFromRect: self.frame)
        self.physicsBody = fieldBody
        self.physicsBody!.affectedByGravity = false
        self.physicsBody!.usesPreciseCollisionDetection = true
        self.physicsBody!.dynamic = true
        self.physicsBody!.mass = 0
        self.physicsBody!.friction = 0
        self.physicsBody!.linearDamping = 0
        self.physicsBody!.angularDamping = 0
        self.physicsBody!.restitution = 1
        self.physicsBody!.categoryBitMask = CollisionTypes.Field.rawValue
        self.physicsBody!.contactTestBitMask = CollisionTypes.Ball.rawValue

        // Prepare the ball - physics engine.
        ball.physicsBody = SKPhysicsBody(circleOfRadius: ball.frame.width/2)
        ball.physicsBody!.affectedByGravity = true
        ball.physicsBody!.restitution = 0.8
        ball.physicsBody!.linearDamping = 0
        ball.physicsBody!.friction = 0.3
        ball.physicsBody!.dynamic = true
        ball.physicsBody!.mass = 0.5
        ball.physicsBody!.allowsRotation = true
        ball.physicsBody!.categoryBitMask = CollisionTypes.Ball.rawValue
        ball.physicsBody!.contactTestBitMask = CollisionTypes.Field.rawValue
        ball.physicsBody!.collisionBitMask = CollisionTypes.Field.rawValue

        //ball.physicsBody!.categoryBitMask = CollideType.Ball.toMask()
        //ball.physicsBody!.collisionBitMask = CollideType.toMask([.Scene, .Ceil, .Floor]) | boards.usedCollideMasks
        //ball.physicsBody!.contactTestBitMask = CollideType.toMask([.Scene, .Ceil, .Floor]) | boards.usedCollideMasks
        ball.hidden = false
        self.addChild(ball)
    }
    func didBeginContact(contact: SKPhysicsContact) {
        if (contact.bodyA.categoryBitMask == CollisionTypes.Field.rawValue &&
            contact.bodyB.categoryBitMask == CollisionTypes.Ball.rawValue) {
            print("contact between field and ball")
        }
    }
}

如您所见，第一个重要的事情是准备physicsWorld(跟踪您的物理必须起作用的边界)，为其指定一个类别，并且所有其他参数需要与其他对象进行交互.然后，您将构建对象的PhysicalBody(在本例中为球).

As you can see, the first important thing is to prepare the physicsWorld (track the boundaries within wich your physics must work), assign it a category and all the other parameters need to interact with the other objects. Then you build the physicsBody of your object , in this case the ball.

这篇关于展开可选值:PhysicsBody-Swift SpriteKit的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！