Easy SpriteKit 接触检测（Space 射击游戏）无法正常工作

Question

我正在尝试制作一个简单的 Space 射击游戏。接触应该发生在鱼雷和外星人之间，或者航天飞机和外星人之间。问题是第二次接触（航天飞机与外星人）只发生在第一种接触（鱼雷与外星人）发生之后，而且它们并不总是精确的。这是在 class

之外创建的结构

struct PhysicsCategory {
static let alien : UInt32 = 1
static let torpedo : UInt32 = 2
static let shuttle : UInt32 = 3 }

班车：

shuttle.physicsBody = SKPhysicsBody(rectangleOfSize: shuttle.size)
shuttle.physicsBody?.categoryBitMask = PhysicsCategory.shuttle
shuttle.physicsBody?.contactTestBitMask = PhysicsCategory.alien 
shuttle.physicsBody?.dynamic = false 
shuttle.physicsBody?.affectedByGravity = false

鱼雷：

torpedo.physicsBody = SKPhysicsBody(rectangleOfSize: torpedo.size)
torpedo.physicsBody?.categoryBitMask = PhysicsCategory.torpedo
torpedo.physicsBody?.contactTestBitMask = PhysicsCategory.alien
torpedo.physicsBody?.affectedByGravity = false
torpedo.physicsBody?.dynamic = false

外星人：

alien.physicsBody = SKPhysicsBody(rectangleOfSize: torpedo.size)
alien.physicsBody?.categoryBitMask = PhysicsCategory.alien
alien.physicsBody?.contactTestBitMask = PhysicsCategory.torpedo
alien.physicsBody?.affectedByGravity = false
alien.physicsBody?.dynamic = true

最后，这是我的联系方式：

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

    if ((firstBody.categoryBitMask == PhysicsCategory.alien) && (secondBody.categoryBitMask == PhysicsCategory.torpedo)) ||
    ((firstBody.categoryBitMask == PhysicsCategory.torpedo) && (secondBody.categoryBitMask == PhysicsCategory.alien)) {
        self.contactWithTorpedo(firstBody.node as! SKSpriteNode, torpedo: secondBody.node as! SKSpriteNode)
    } else if ((firstBody.categoryBitMask == PhysicsCategory.shuttle) && (secondBody.categoryBitMask == PhysicsCategory.alien)) {
            self.contactWithShuttle(firstBody.node as! SKSpriteNode, shuttle: secondBody.node as! SKSpriteNode)
    }
}


func contactWithTorpedo (alien: SKSpriteNode, torpedo : SKSpriteNode) {
    alien.removeFromParent()
    torpedo.removeFromParent()
    score++
    scoreLabel.text = "score: " + "\(score)"
}

func contactWithShuttle (alien:SKSpriteNode, shuttle:SKSpriteNode) {
    alien.removeFromParent()
    shuttle.removeFromParent()

    self.view?.presentScene(EndScene())

}

我不太确定问题出在哪里，而且我看到一些教程也是如此。顺便说一句，我不知道它是否相关，但这不是 iOS 游戏而是 OSX 游戏。提前致谢！

Answer 1

我建议您阅读有关 SKPhysicsBody 的文档。

Every physics body in a scene can be assigned to up to 32 different categories, each corresponding to a bit in the bit mask. You define the mask values used in your game. In conjunction with the collisionBitMask and contactTestBitMask properties, you define which physics bodies interact with each other and when your game is notified of these interactions

首先，我会将 PhysicsCategory 更改为

struct PhysicsCategory {
static let alien : UInt32 = 0x1 << 1
static let torpedo : UInt32 = 0x1 << 2
static let shuttle : UInt32 = 0x1 << 3 
}

然后

alien.physicsBody?.contactTestBitMask = PhysicsCategory.torpedo | PhysicsCategory.shuttle

希望对您有所帮助。

Answer 2

所以我昨天确实设法解决了我的问题。我正在发布更新的代码以防它可以帮助某人。 class外：

struct PhysicsCategory {
static let player : UInt32 = 0x1 << 0
static let bullet : UInt32 = 0x1 << 1
static let enemy : UInt32 = 0x1 << 2}

然后，在像我之前写的那样对每个精灵应用物理之后，在 class:

    //Contact with bullet
func contactWithBullet(enemy : SKSpriteNode, bullet: SKSpriteNode) {
    enemy.removeFromParent()
    bullet.removeFromParent()
    score += 1
    updateLabels()
}

//contact with player
func contactWithPlayer(player : SKSpriteNode, enemy : SKSpriteNode) {
    enemy.removeFromParent()
    lives -= 1
    updateLabels() //another function that changes the score and lives labels
}
//CONTACT DETECTION
func didBeginContact(contact: SKPhysicsContact) {
    let firstBody : SKPhysicsBody = contact.bodyA
    let secondBody : SKPhysicsBody = contact.bodyB

    if (firstBody.categoryBitMask == PhysicsCategory.enemy && secondBody.categoryBitMask == PhysicsCategory.bullet || firstBody.categoryBitMask == PhysicsCategory.bullet && secondBody.categoryBitMask == PhysicsCategory.enemy) {
        contactWithBullet(firstBody.node as! SKSpriteNode, bullet: secondBody.node as! SKSpriteNode)
        checkScore()
        enemiesInWave -= 1
    } else if (firstBody.categoryBitMask == PhysicsCategory.enemy && secondBody.categoryBitMask == PhysicsCategory.player || firstBody.categoryBitMask == PhysicsCategory.player && secondBody.categoryBitMask == PhysicsCategory.enemy) {
        contactWithPlayer(firstBody.node as! SKSpriteNode, enemy: secondBody.node as! SKSpriteNode)
        checkLives()
        enemiesInWave -= 1
    }
}

Answer 3

您可能会发现按如下方式重组您的 didBeginContact 不会那么混乱，因为这避免了 firstBody/secondbody 内容和复杂的 if...then 条件来查看什么联系了什么：

func didBeginContact(contact: SKPhysicsContact) {
    let contactMask = contact.bodyA.categoryBitMask | contact.bodyB.categoryBitMask

    switch contactMask {
    case PhysicsCategory.alien | PhysicsCategory.torpedo:
       // alien and torpedo have contacted
       contact.bodyA.removeFromParent()
       contact.bodyB.removeFromParent()
       score += 1
       scoreLabel.text = "score: " + "\(score)"

    case PhysicsCategory.alien | PhysicsCategory.shuttle:
       // alien and shuttle have contacted
       contact.bodyA.removeFromParent()
       contact.bodyB.removeFromParent()

       self.view?.presentScene(EndScene())

    default :
        //Some other contact has occurred
        print("Some other contact")
    }
}

您可以根据需要为您必须在游戏中采取行动的所有联系人添加任意数量的 PhysicsCategory.enemy | PhysicsCategory.player 个案例。对每个潜在联系人单独编码，您就不会在 if...then...else 中迷失自己。

如果您只需要引用接触中涉及的节点之一（例如，在敌人击中玩家后移除玩家），您可以这样做：

let playerNode = contact.bodyA.categoryBitMask == PhysicsCategory.player ? contact.bodyA.node! : contact.bodyB.node!
playernode.removefromParent

Easy SpriteKit 接触检测（Space 射击游戏）无法正常工作

Easy SpriteKit Contact Detection (Space Shooter Game) Not Wotking Properly

collision-detection

uint32

sprite-kit

swift

xcode6