如何在精灵工具包中检测不同类型的碰撞

Question

我想在SpriteKit中检测两种不同类型的碰撞:

当气球击中目标1和球2击中目标2时:

到目前为止，我已经添加了不同的物理类别:

struct physicsCategory {
    static let ballOne :UInt32 = 0x1 << 0
    static let goalOne :UInt32 = 0x1 << 1
    static let ballTwo :UInt32 = 0x1 << 2
    static let goalTwo :UInt32 = 0x1 << 3
}

以下是我班级的相关部分：

class gameScene: SKScene, SKPhysicsContactDelegate {

    var borderBody:SKPhysicsBody!

    var myscore:Int = 0
    var opponentScore:Int = 10

    override func sceneDidLoad() {

        super.sceneDidLoad()
        physicsWorld.contactDelegate = self

    }

    func didBegin(_ contact: SKPhysicsContact) {

        let firstBody = contact.bodyA.node as! SKSpriteNode
        let secondBody = contact.bodyB.node as! SKSpriteNode

        if ((firstBody.name == "ballOne") && (secondBody.name == "goalOne")) {
            collisionGoalOne(BallOne: firstBody, GoalOne: secondBody)
        }

        else {

        }
    }

    func collisionGoalOne(BallOne: SKSpriteNode, GoalOne: SKSpriteNode) {
        addScore()
    }

    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {

        let touch = touches.first
        let touchLocation = touch!.location(in: self)

        let ballOne = childNode(withName: "ballOne") as! SKSpriteNode
        ballOne.physicsBody?.categoryBitMask = physicsCategory.ballOne
        ballOne.physicsBody?.collisionBitMask = physicsCategory.goalOne
        ballOne.physicsBody?.contactTestBitMask = physicsCategory.goalOne
        ballOne.physicsBody?.isDynamic = true

        let goalOne = childNode(withName: "goalOne") as! SKSpriteNode
        goalOne.physicsBody?.categoryBitMask = physicsCategory.goalOne
        goalOne.physicsBody?.collisionBitMask = physicsCategory.ballOne
        goalOne.physicsBody?.contactTestBitMask = physicsCategory.ballOne
        goalOne.physicsBody?.isDynamic = false        
    }

}

现在，当球与墙上相撞时，应用程序崩溃

让firstBody=contact.bodyA.node！SKSpriteNode

with“无法将“appname . games scene”(0x 105320)类型的值转换为“SKSpriteNode”(0x 1877 b5c)。”

我很想知道为什么会发生这种崩溃，以及这是否是一种处理碰撞的好方法。谢谢你。

Answer 1

我认为你可能想做一些改变。

当你的球节点接触墙壁时，我相信你的didBEGIN（_联系人：SK物理接触）方法被调用，一个身体作为球（SKNode），另一个身体作为场景边界（SKScene）。

强制将 SKScene 投射到 SKSprite节点与让第一个正文 = 接触.bodyA.节点作为 ！SKS精灵节点崩溃，正如RT5754所指出的那样。

要解决此问题，您可以考虑以下事项：

>

为墙/边框添加一个物理类别。类似于：

 static let sceneBorder :UInt32 = 0x1 << 4

更新边界和球节点以具有碰撞物理效果：

ballNode.physicsBody?.collisionBitMask = physicsCategory.sceneBorder
borderNode.physicsBody?.collisionBitMask = physicsCategory.ballOne + physicsCategory.ballTwo

在处理其他联系逻辑时，我的didBegin（_contact:SKPhysicsContact）模式如下：

func didBegin(_ contact: SKPhysicsContact) {
  var firstBody: SKPhysicsBody = contact.bodyA
  var secondBody: SKPhysicsBody = contact.bodyB

  //in did begin contact, order the bodies by physics category
  if firstBody.categoryBitMask > secondBody.categoryBitMask {
    let temp = secondBody
    secondBody = firstBody
    firstBody = temp
  }

  //logic to handle contact is based on physicsCategory
  if secondBody.categoryBitMask == physicsCategory.whatever {
    methodToHandleWhatever(thingOne: firstBody, thingTwo: secondBody)
  }

Answer 2

第一正文可能无法转换为SKSpriteNode，因此只有在检查哪些节点发生冲突后才能创建该变量。

请注意，ballOne可以是bodyA或bodyB，因此请更改您的代码来检查这两种可能性。

我稍微更改了您的代码。希望这有帮助

if ((contact.bodyA.node?.name == "ballOne") && (contact.bodyB.node?.name == "goalOne")) {  
     let firstBody = contact.bodyA.node as! SKSpriteNode
     let secondBody = contact.bodyB.node as! SKSpriteNode
     collisionGoalOne(BallOne: firstBody, GoalOne: secondBody)
 } else if ((contact.bodyA.node?.name == "goalOne") && (contact.bodyB.node?.name == "ballOne")) {
     let firstBody = contact.bodyA.node as! SKSpriteNode
     let secondBody = contact.bodyB.node as! SKSpriteNode
     collisionGoalOne(BallOne: secondBody, GoalOne: firstBody)
}