將SKSpriteNode移動到觸摸位置

Question

上面是我的遊戲的圖像。自上而下的遊戲。無論玩家在屏幕上觸摸什麼位置，我都希望子彈能夠持續一段時間到達該位置。我也希望玩家能夠在屏幕上拖動他的手指，同樣的事情發生。這樣玩家每次想要拍攝時都不必觸摸屏幕。

到目前爲止，我已經嘗試了一些不同的東西，但似乎沒有任何工作。

首先，我不知道我是否應該有一個單獨的子彈功能。但無論如何，這是我的子彈功能。

func spawnBullets() { 
    let bullet = SKSpriteNode(imageNamed: "Bullet") 
    bullet.name = "Bullet" 
    bullet.zPosition = 4 
    bullet.position = CGPoint(x: player.position.x + 19, y: 
    player.position.y) 
    self.addChild(bullet) 
} 

我也有在didMove功能子彈了 「定時器」：

var timer = Timer.scheduledTimer(timeInterval: 0.1, target: self, 
selector: Selector("spawnBullets"), userInfo: nil, repeats: true) 

最後，這是我的touchesBegan功能：

override func touchesBegan(_ touches: Set<UITouch>, with event: 
UIEvent?) {   
    for touch in touches {    
     let location = touch.location(in: self)    
     let moveToPoint = SKAction.move(to: location, duration: 0.5) 
     let repeatAction = SKAction.repeatForever(moveToPoint)    
     bullet.run(moveToPoint) 
    } 

} 

Answer 1

在這裏你去 - 一個簡單的應用程序，您可以在屏幕上拖動屏幕，並向觸摸位置發射導彈。

如果你觸摸船隻，你可以拖動它;觸及船外，導彈將從船上射向觸摸位置。

import SpriteKit 

class GameScene: SKScene { 

var ship = SKSpriteNode() 
var shipIsTouched = false 
var missileDestination = CGPoint() 
let missileSpeed: CGFloat = 800 // Points per second) 
let missileFireRate : TimeInterval = 0.2 // Seconds between each missile 

override func didMove(to view: SKView) { 
    missileDestination = CGPoint(x: 0, y: (self.size.height/2)) 
    createPlayerShip() 
    let fire = SKAction.sequence([SKAction.run(fireMissile), SKAction.wait(forDuration: missileFireRate)]) 
    run(SKAction.repeatForever(fire)) 
} 

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) { 
    if let touch = touches.first { 
     if ship.contains(touch.location(in: self)) { 
      shipIsTouched = true 
     } else { 
      missileDestination = touch.location(in: self) 
      ship.zRotation = direction(to: missileDestination, from: ship.position) - CGFloat(Double.pi/2) 
     } 
    } 
} 

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) { 
    if (shipIsTouched == true) { 
     ship.position = (touches.first?.location(in: self))! 
     ship.zRotation = direction(to: missileDestination, from: ship.position) - CGFloat(Double.pi/2) 
    } 
} 

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) { 
    if shipIsTouched { 
     shipIsTouched = false 
    } 
} 

override func update(_ currentTime: TimeInterval) { 
    // Called before each frame is rendered 
} 

func createPlayerShip() { 
    ship = SKSpriteNode(imageNamed: "Spaceship") 
    ship.zRotation = CGFloat(-Double.pi/2.0) 
    ship.scale(to: CGSize(width: 150, height: 150)) 
    ship.position = CGPoint(x: -size.width/2 + 200, y: 0) 

    addChild(ship) 
} 


func fireMissile() { 
    let missile = SKSpriteNode(color: .white, size: CGSize(width: 50, height: 10)) 
    missile.position = ship.position 

    let missileFlightTime = travelTime(to: missileDestination, from: ship.position, atSpeed: missileSpeed) 
    missile.zRotation = direction(to: missileDestination, from: missile.position) 

    addChild(missile) 

    let missileMove = SKAction.move(to: missileDestination, 
            duration: TimeInterval(missileFlightTime)) 
    let missileRemove = SKAction.removeFromParent() 
    missile.run(SKAction.sequence([missileMove, missileRemove])) 
} 

func travelTime(to target : CGPoint, from : CGPoint, atSpeed speed : CGFloat) -> TimeInterval { 
    let distance = sqrt(pow(abs(target.x - from.x),2) + 
     pow(abs(target.y - from.y),2)) 
    return TimeInterval(distance/speed) 
} 


func direction(to target : CGPoint, from: CGPoint) -> CGFloat { 
    let x = target.x - from.x 
    let y = target.y - from.y 
    var angle = atan(y/x) 
    if x < 0 { 
     angle = angle + CGFloat.pi 
    } 
    return angle 
} 
} 

有一點額外的詭計，使導彈的速度是一致的（自的moveTo需要時間，而不是速度，因此，如果目標是接近的導彈會慢慢移動，如果再遠，他們會移動更快），並使導彈旋轉以面對目的地。

您可以爲導彈追蹤到目的地創建曲線路徑，這看起來很酷，但可能不適合您的應用。

編輯：

如果你想船平穩，而導彈跟隨你的手指，更換所有的代碼到createPlayerShip這個（是的，我們已經失去了touchesEnded()和update()：

import SpriteKit 

class GameScene: SKScene { 

var ship = SKSpriteNode() 
var missileDestination = CGPoint() 
let missileSpeed: CGFloat = 800 // Points per second) 
let missileFireRate : TimeInterval = 0.2 // Seconds between each missile 

override func didMove(to view: SKView) { 
    missileDestination = CGPoint(x: size.height/2, y: 0) 
    createPlayerShip() 
    let fire = SKAction.sequence([SKAction.run(fireMissile), SKAction.wait(forDuration: missileFireRate)]) 
    run(SKAction.repeatForever(fire)) 
} 

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) { 
    if let touch = touches.first { 
      missileDestination = touch.location(in: self) 
    } 
} 

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) { 
     missileDestination = (touches.first?.location(in: self))! 
}