ios - SpriteKit 和 Swift，如果条件为真，则将平台设置为 nil 将不起作用

Question

您好，我正在使用 swift 在 spritekit 中制作一个简单的 2d sidescroller 游戏，我遇到了一个我无法解决的问题。我有一个名为 (createPlatforms) 的函数来生成一些平台(每个平台都在另一个平台之上)并且平台从右到左移动。我还添加了一个名为 isJumping 的 Bool 变量，我希望如果变量 isJumping 为真，则平台 physicsbody 的值为 nil，以便玩家可以跳到它上面并降落在它上面。我有点设法做到了。它适用于第一个平台，但不适用于其他平台。玩家跳到第一个平台上方并降落在上面，但他不能跳到第二个或第三个平台上方。有时大约有 10% 的时间它适用于所有平台，他可以跳到上面并降落在它们上，但大多数时候它不起作用。

提前谢谢你。

我的跳转方法:

func jump() {

    isJumping = true

    let jumpBlock = SKAction.runBlock({
        () in
        self.Dragon.physicsBody?.velocity = CGVectorMake(0, 0)
        self.Dragon.physicsBody?.applyImpulse(CGVectorMake(0, 140))  // Jump Impulse
    })

    self.runAction(jumpBlock)

    runAfterDelay(0.3) { /* 0.3 Seconds */ 
        self.isJumping = false 
    }
}
 //Delay function
 func runAfterDelay(delay: NSTimeInterval, block: dispatch_block_t) {
    let time = dispatch_time(DISPATCH_TIME_NOW, Int64(delay * Double(NSEC_PER_SEC)))
    dispatch_after(time, dispatch_get_main_queue(), block)
}

生成平台的方法:

 func createPlatforms() {

    Platform1 = SKSpriteNode(imageNamed:"Platform")
    Platform2 = SKSpriteNode(imageNamed:"Platform")
    Platform3 = SKSpriteNode(imageNamed:"Platform-Small")

    Platform1.size = CGSize(width: frame.width / 3, height: frame.height / 25)
    Platform2.size = CGSize(width: frame.width / 3, height: frame.height / 25)
    Platform3.size = CGSize(width: frame.width / 6, height: frame.height / 25)
    Platform1.position = CGPoint(x: self.frame.width + 330, y: self.frame.height - 285)
    Platform2.position = CGPoint(x: self.frame.width + 500, y: self.frame.height - 210)
    Platform3.position = CGPoint(x: self.frame.width + 570, y: self.frame.height - 135)

    Platform1.physicsBody = SKPhysicsBody(rectangleOfSize: Platform1.size)
    Platform1.zPosition = 6
    Platform1.physicsBody?.categoryBitMask = PhysicsCatagory.Platform1
    Platform1.physicsBody?.contactTestBitMask = PhysicsCatagory.Dragon
    Platform1.physicsBody?.collisionBitMask = PhysicsCatagory.Dragon
    Platform1.physicsBody?.dynamic = false

    Platform2.physicsBody = SKPhysicsBody(rectangleOfSize: Platform2.size)
    Platform2.zPosition = 7
    Platform2.physicsBody?.categoryBitMask = PhysicsCatagory.Platform2
    Platform2.physicsBody?.contactTestBitMask = PhysicsCatagory.Dragon
    Platform2.physicsBody?.collisionBitMask = PhysicsCatagory.Dragon
    Platform2.physicsBody?.dynamic = false

    Platform3.physicsBody = SKPhysicsBody(rectangleOfSize: Platform3.size)
    Platform3.zPosition = 8
    Platform3.physicsBody?.categoryBitMask = PhysicsCatagory.Platform3
    Platform3.physicsBody?.contactTestBitMask = PhysicsCatagory.Dragon
    Platform3.physicsBody?.collisionBitMask = PhysicsCatagory.Dragon
    Platform3.physicsBody?.dynamic = false

    Platform1.runAction(moveAndRemove)
    Platform2.runAction(moveAndRemove)
    Platform3.runAction(moveAndRemove)

    self.addChild(Platform1)
    self.addChild(Platform2)
    self.addChild(Platform3)

    let distance = CGFloat(self.frame.width + 1000)
    let moveGroundObjects = SKAction.moveByX(-distance * 1.3, y: 0, duration: NSTimeInterval(0.011 * distance))
    let removeGroundObjects = SKAction.removeFromParent()
    moveAndRemove = SKAction.sequence([moveGroundObjects, removeGroundObjects])


    runAfterDelay(7) {
        self.createPlatforms()
    }
}

让platform的physicbody为nil的方法:

func makePlatformsNil() {

    if isJumping == true {

        Platform1.physicsBody = nil
        Platform2.physicsBody = nil
        Platform3.physicsBody = nil

    }  else if isJumping == false {

        Platform1.physicsBody = SKPhysicsBody(rectangleOfSize:  Platform1.size)
        Platform1.physicsBody?.categoryBitMask = PhysicsCatagory.Platform1
        Platform1.physicsBody?.collisionBitMask = PhysicsCatagory.Dragon
        Platform1.physicsBody?.contactTestBitMask = PhysicsCatagory.Dragon
        Platform1.physicsBody?.dynamic = false
        Platform1.physicsBody?.allowsRotation = false

        Platform2.physicsBody = SKPhysicsBody(rectangleOfSize: Platform2.size)
        Platform2.physicsBody?.categoryBitMask = PhysicsCatagory.Platform2
        Platform2.physicsBody?.collisionBitMask = PhysicsCatagory.Dragon
        Platform2.physicsBody?.contactTestBitMask = PhysicsCatagory.Dragon
        Platform2.physicsBody?.dynamic = false
        Platform2.physicsBody?.affectedByGravity = false

        Platform3.physicsBody = SKPhysicsBody(rectangleOfSize: Platform3.size)
        Platform3.physicsBody?.categoryBitMask = PhysicsCatagory.Platform3
        Platform3.physicsBody?.collisionBitMask = PhysicsCatagory.Dragon
        Platform3.physicsBody?.contactTestBitMask = PhysicsCatagory.Dragon
        Platform3.physicsBody?.dynamic = false
        Platform3.physicsBody?.affectedByGravity = false
    }
}

有人可以帮帮我吗？我因为三个弱点而陷入困境，我现在真的很沮丧:-/我相信我的问题可以由比我更有编码经验的人轻松解决

Answer 1

这里的代码少了很多，更干净也更容易管理。 (所有平台应该共享同一个类别，Dragon类别需要小于Platform)

注意:未在 XCode 上进行验证测试

func didBeginContact(contact: SKPhysicsContact) {
    let (firstBody,secondBody) = (contact.bodyA.categoryBitMask <= contact.bodyB.categoryBitMask) ? (contact.bodyA,contact.bodyB) : (contact.bodyB,contact.bodyA) 

    // check if on Platform

    if (firstBody.categoryBitMask == PhysicsCatagory.Dragon && secondBody.categoryBitMask == PhysicsCatagory.Platform)  {

        if firstBody.velocity.dy < -0.0 {

            secondBody.collisionBitMask |= physicsCatagory.Dragon
        }

    }



}

func didEndContact(contact: SKPhysicsContact) {
    let (firstBody,secondBody) = (contact.bodyA.categoryBitMask <= contact.bodyB.categoryBitMask) ? (contact.bodyA,contact.bodyB) : (contact.bodyB,contact.bodyA) 

    // check if on Platform

    if (firstBody.categoryBitMask == PhysicsCatagory.Dragon && secondBody.categoryBitMask == PhysicsCatagory.Platform)  {

       //No matter what way dragon is moving, if he is off the platform,  let's turn off the collision

            secondBody.collisionBitMask &= ~(physicsCatagory.Dragon)


    }

}