Sprite Kit 初学指南

func + (left: CGPoint, right: CGPoint) -> CGPoint {
  return CGPoint(x: left.x + right.x, y: left.y + right.y)
}

func - (left: CGPoint, right: CGPoint) -> CGPoint {
  return CGPoint(x: left.x - right.x, y: left.y - right.y)
}

func * (point: CGPoint, scalar: CGFloat) -> CGPoint {
  return CGPoint(x: point.x * scalar, y: point.y * scalar)
}

func / (point: CGPoint, scalar: CGFloat) -> CGPoint {
  return CGPoint(x: point.x / scalar, y: point.y / scalar)
}

#if !(arch(x86_64) || arch(arm64))
func sqrt(a: CGFloat) -> CGFloat {
  return CGFloat(sqrtf(Float(a)))
}
#endif

extension CGPoint {
  func length() -> CGFloat {
    return sqrt(x*x + y*y)
  }

  func normalized() -> CGPoint {
    return self / length()
  }
}

override func touchesEnded(touches: Set, withEvent event: UIEvent?) {

  // 1 - Choose one of the touches to work with
  guard let touch = touches.first else {
    return
  }
  let touchLocation = touch.locationInNode(self)

  // 2 - Set up initial location of projectile
  let projectile = SKSpriteNode(imageNamed: "projectile")
  projectile.position = player.position

  // 3 - Determine offset of location to projectile
  let offset = touchLocation - projectile.position

  // 4 - Bail out if you are shooting down or backwards
  if (offset.x < 0) { return }

  // 5 - OK to add now - you've double checked position
  addChild(projectile)

  // 6 - Get the direction of where to shoot
  let direction = offset.normalized()

  // 7 - Make it shoot far enough to be guaranteed off screen
  let shootAmount = direction * 1000

  // 8 - Add the shoot amount to the current position
  let realDest = shootAmount + projectile.position

  // 9 - Create the actions
  let actionMove = SKAction.moveTo(realDest, duration: 2.0)
  let actionMoveDone = SKAction.removeFromParent()
  projectile.runAction(SKAction.sequence([actionMove, actionMoveDone]))

}

struct PhysicsCategory {
  static let None      : UInt32 = 0
  static let All       : UInt32 = UInt32.max
  static let Monster   : UInt32 = 0b1       // 1
  static let Projectile: UInt32 = 0b10      // 2
}

class GameScene: SKScene, SKPhysicsContactDelegate {

physicsWorld.gravity = CGVectorMake(0, 0)
physicsWorld.contactDelegate = self

monster.physicsBody = SKPhysicsBody(rectangleOfSize: monster.size) // 1
monster.physicsBody?.dynamic = true // 2
monster.physicsBody?.categoryBitMask = PhysicsCategory.Monster // 3
monster.physicsBody?.contactTestBitMask = PhysicsCategory.Projectile // 4
monster.physicsBody?.collisionBitMask = PhysicsCategory.None // 5

projectile.physicsBody = SKPhysicsBody(circleOfRadius: projectile.size.width/2)
projectile.physicsBody?.dynamic = true
projectile.physicsBody?.categoryBitMask = PhysicsCategory.Projectile
projectile.physicsBody?.contactTestBitMask = PhysicsCategory.Monster
projectile.physicsBody?.collisionBitMask = PhysicsCategory.None
projectile.physicsBody?.usesPreciseCollisionDetection = true

func projectileDidCollideWithMonster(projectile:SKSpriteNode, monster:SKSpriteNode) {
  print("Hit")
  projectile.removeFromParent()
  monster.removeFromParent()
}

func didBeginContact(contact: SKPhysicsContact) {

  // 1
  var firstBody: SKPhysicsBody
  var secondBody: SKPhysicsBody
  if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
    firstBody = contact.bodyA
    secondBody = contact.bodyB
  } else {
    firstBody = contact.bodyB
    secondBody = contact.bodyA
  }

  // 2
  if ((firstBody.categoryBitMask & PhysicsCategory.Monster != 0) &&
      (secondBody.categoryBitMask & PhysicsCategory.Projectile != 0)) {
    projectileDidCollideWithMonster(firstBody.node as! SKSpriteNode, monster: secondBody.node as! SKSpriteNode)
  }

}

let backgroundMusic = SKAudioNode(fileNamed: "background-music-aac.caf")
backgroundMusic.autoplayLooped = true
addChild(backgroundMusic)

runAction(SKAction.playSoundFileNamed("pew-pew-lei.caf", waitForCompletion: false))

import Foundation
import SpriteKit

class GameOverScene: SKScene {

  init(size: CGSize, won:Bool) {

    super.init(size: size)

    // 1
    backgroundColor = SKColor.whiteColor()

    // 2
    let message = won ? "You Won!" : "You Lose :["

    // 3
    let label = SKLabelNode(fontNamed: "Chalkduster")
    label.text = message
    label.fontSize = 40
    label.fontColor = SKColor.blackColor()
    label.position = CGPoint(x: size.width/2, y: size.height/2)
    addChild(label)

    // 4
    runAction(SKAction.sequence([
      SKAction.waitForDuration(3.0),
      SKAction.runBlock() {
        // 5
        let reveal = SKTransition.flipHorizontalWithDuration(0.5)
        let scene = GameScene(size: size)
        self.view?.presentScene(scene, transition:reveal)
      }
    ]))

  }

  // 6
  required init(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }
}

let loseAction = SKAction.runBlock() {
  let reveal = SKTransition.flipHorizontalWithDuration(0.5)
  let gameOverScene = GameOverScene(size: self.size, won: false)
  self.view?.presentScene(gameOverScene, transition: reveal)
}
monster.runAction(SKAction.sequence([actionMove, loseAction, actionMoveDone]))

var monstersDestroyed = 0

monstersDestroyed++
if (monstersDestroyed > 30) {
  let reveal = SKTransition.flipHorizontalWithDuration(0.5)
  let gameOverScene = GameOverScene(size: self.size, won: true)
  self.view?.presentScene(gameOverScene, transition: reveal)
}