swift - 如何使用滑动手势控制 Sprite ，使 Sprite 可以沿 x 轴移动

Question

目前我有一个游戏，可以使用设备的加速计控制 Sprite 并沿 x 轴(具有固定的 y 位置)移动。我希望更改此设置，以便用户可以通过在屏幕上拖动来控制 Sprite ，就像在流行游戏(例如贪吃蛇 vs. 方 block )中一样。

我已经尝试使用触摸移动方法，它给出了正确的效果，尽管 Sprite 首先移动到我不想要的用户触摸的位置。

下面是我一直用来实验的环境，移动的触摸给出了我想要的正确的控制类型，尽管我似乎不知道如何阻止 Sprite 在触摸之前首先移动到触摸的位置滑动/拖动

import SpriteKit
import GameplayKit

var player = SKSpriteNode()
var playerColor = UIColor.orange
var background = UIColor.black
var playerSize = CGSize(width: 50, height: 50)
var touchLocation = CGPoint()
var shape = CGPoint()
class GameScene: SKScene {

  override func didMove(to view: SKView) {
    self.backgroundColor = background

    spawnPlayer()    
}

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in touches{
        let touchLocation = touch.location(in: self)
        player.position.x = touchLocation.x
    }
}

func spawnPlayer(){    
    player = SKSpriteNode(color: playerColor, size: playerSize)
    player.position = CGPoint(x:50, y: 500)

    self.addChild(player)
}

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

总之，我正在寻找与蛇与 block 相同的控制 Sprite 的方法

Answer 1

嘿，所以你的想法是正确的，你需要存储以前的touchesMovedPoint。然后用它来确定每次调用 TouchMoved 时手指移动了多远。然后将这个数量添加到玩家的当前位置。

var lastTouchLoc:CGPoint = CGPoint()

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in touches{
        let touchLocation = touch.location(in: self)

        let dx = touchLocation.x - lastTouchLoc.x
        player.position.x += dx // Change the players current position by the distance between the previous touchesMovedPoint and the current one.
        lastTouchLoc.x = touchLocation.x // Update last touch location
    }
}


override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in touches {
         // When releasing the screen from point "E" we don't want dx being calculated from point "E".
        // We want dx to calculate from the most recent touchDown point
        let initialTouchPoint =  touch.location(in: self)
        lastTouchLoc.x = initialTouchPoint.x
    }
}