我正在尝试使用本教程作为参考，在我的游戏中实现一个简单的评分系统：
http://www.raywenderlich.com/87232/make-game-like-mega-jump-sprite-kit-swift-part-2 http://www.raywenderlich.com/87232/make-game-like-mega-jump-sprite-kit-swift-part-2
问题是，如果我尝试按原样实现，它会在 GameScene.swift 的这一行中崩溃：
let another = whichNode as! GameObjectNode
以下是玩家收集硬币的代码的主要部分。如果您想更仔细、更好地了解，我也可以邀请您访问我的存储库。我知道查看我粘贴在这里的代码可能会很困难。
游戏对象节点.swift：
enum CoinType: Int {
case Normal = 0
case Special
}
struct CollisionCategoryBitmask {
static let Player: UInt32 = 0x00
static let Coin: UInt32 = 0x01
static let Platform: UInt32 = 0x02
}
class GameObjectNode: SKNode {
func collisionWithPlayer(player: SKNode) -> Bool {
return false
}
func checkNodeRemoval(playerY: CGFloat) {
if playerY > self.position.y + 300.0 {
self.removeFromParent()
}
}
}
class CoinNode: GameObjectNode {
let coinSound = SKAction.playSoundFileNamed("StarPing.wav", waitForCompletion: false)
var coinType: CoinType!
override func collisionWithPlayer(player: SKNode) -> Bool {
// Boost the player up
player.physicsBody?.velocity = CGVector(dx: player.physicsBody!.velocity.dx, dy: 400.0)
// Play sound
runAction(coinSound, completion: {
// Remove this Star
self.removeFromParent()
})
// Award score
GameState.sharedInstance.score += (coinType == .Normal ? 20 : 100)
// Award stars
GameState.sharedInstance.coins += (coinType == .Normal ? 1 : 5)
// The HUD needs updating to show the new stars and score
return true
}
}
GameState.swift
class GameState {
var score: Int
var highScore: Int
var coins: Int
init() {
// Init
score = 0
highScore = 0
coins = 0
// Load game state
let defaults = NSUserDefaults.standardUserDefaults()
highScore = defaults.integerForKey("highScore")
coins = defaults.integerForKey("coins")
}
func saveState() {
// Update highScore if the current score is greater
highScore = max(score, highScore)
// Store in user defaults
let defaults = NSUserDefaults.standardUserDefaults()
defaults.setInteger(highScore, forKey: "highScore")
defaults.setInteger(coins, forKey: "coins")
NSUserDefaults.standardUserDefaults().synchronize()
}
class var sharedInstance: GameState {
struct Singleton {
static let instance = GameState()
}
return Singleton.instance
}
}
和 GameScene.swift：
import SpriteKit
import CoreMotion
import GameplayKit
struct PhysicsCategory {
static let None: UInt32 = 0
static let Player: UInt32 = 0b1 // 1
static let PlatformNormal: UInt32 = 0b10 // 2
static let PlatformBreakable: UInt32 = 0b100 // 4
static let CoinNormal: UInt32 = 0b1000 // 8
static let CoinSpecial: UInt32 = 0b10000 // 16
static let Edges: UInt32 = 0b100000 // 32
}
class GameScene: SKScene, SKPhysicsContactDelegate {
// Other Properties
...
var player: SKSpriteNode!
// HUD
var hudNode: SKNode!
var lblScore: SKLabelNode!
var lblCoins: SKLabelNode!
override func didMoveToView(view: SKView) {
....
// HUD
hudNode = SKNode()
hudNode.zPosition = 1000
cameraNode.addChild(hudNode)
// Coins
let coin = SKSpriteNode(imageNamed: "powerup05_1")
coin.position = convertPoint(CGPoint(x: 300, y: self.size.height-100), toNode: cameraNode)
coin.zPosition = 1000
hudNode.addChild(coin)
lblCoins = SKLabelNode(fontNamed: "ChalkboardSE-Bold")
lblCoins.fontSize = 70
lblCoins.fontColor = SKColor.whiteColor()
lblCoins.position = convertPoint(CGPoint(x: 375, y: self.size.height-100), toNode: cameraNode)
lblCoins.horizontalAlignmentMode = SKLabelHorizontalAlignmentMode.Left
lblCoins.zPosition = 1000
lblCoins.text = String(format: "X %d", GameState.sharedInstance.coins)
hudNode.addChild(lblCoins)
// Score
// 4
lblScore = SKLabelNode(fontNamed: "ChalkboardSE-Bold")
lblScore.fontSize = 70
lblScore.fontColor = SKColor.whiteColor()
lblScore.position = convertPoint(CGPoint(x: self.size.width-325, y: self.size.height-100), toNode: cameraNode)
lblScore.horizontalAlignmentMode = SKLabelHorizontalAlignmentMode.Right
lblScore.zPosition = 1000
lblScore.text = "0"
hudNode.addChild(lblScore)
}
func setupNodes() {
...
player = fgNode.childNodeWithName("Player") as! SKSpriteNode
}
func createStarAtPosition(position: CGPoint, ofType type: CoinType) -> CoinNode {
// 1
let node = CoinNode()
let thePosition = CGPoint(x: position.x * scaleFactor, y: position.y)
node.position = thePosition
node.name = "NODE_COIN"
// 2
node.coinType = type
var sprite: SKSpriteNode
if type == .Special {
sprite = SKSpriteNode(imageNamed: "CoinSpecial")
} else {
sprite = SKSpriteNode(imageNamed: "Coin")
}
node.addChild(sprite)
// 3
node.physicsBody = SKPhysicsBody(circleOfRadius: sprite.size.width / 2)
// 4
node.physicsBody?.dynamic = false
node.physicsBody?.categoryBitMask = CollisionCategoryBitmask.Coin
node.physicsBody?.collisionBitMask = 0
node.physicsBody?.contactTestBitMask = 0
return node
}
func didBeginContact(contact: SKPhysicsContact) {
let other = contact.bodyA.categoryBitMask == PhysicsCategory.Player ? contact.bodyB : contact.bodyA
var updateHUD = false
let whichNode = (contact.bodyA.node != player) ? contact.bodyA.node : contact.bodyB.node
// Code crashes here
let another = whichNode as! GameObjectNode
updateHUD = another.collisionWithPlayer(player)
if updateHUD {
lblCoins.text = String(format: "X %d", GameState.sharedInstance.coins)
lblScore.text = String(format: "%d", GameState.sharedInstance.score)
}
switch other.categoryBitMask {
case PhysicsCategory.CoinNormal:
if let coin = other.node as? SKSpriteNode {
emitParticles("CollectNormal", sprite: coin)
jumpPlayer()
runAction(soundCoin)
}
case PhysicsCategory.CoinSpecial:
if let coin = other.node as? SKSpriteNode {
emitParticles("CollectSpecial", sprite: coin)
boostPlayer()
runAction(soundBoost)
}
case PhysicsCategory.PlatformNormal:
if let platform = other.node as? SKSpriteNode {
if player.physicsBody!.velocity.dy < 0 {
platformAction(platform, breakable: false)
jumpPlayer()
runAction(soundJump)
}
}
case PhysicsCategory.PlatformBreakable:
if let platform = other.node as? SKSpriteNode {
if player.physicsBody!.velocity.dy < 0 {
platformAction(platform, breakable: true)
jumpPlayer()
runAction(soundBrick)
}
}
default:
break;
}
}
