如何在 Swift 中拍摄移动的精灵？

Question

我正试图让我的静止怪物向我移动的玩家射击。玩家位置和怪物位置都在获取正确的值，并且此代码编写在每秒调用的函数中。现在弹丸出现了，但并没有从怪物身上移开。除了 .applyAngularImpulse 之外，我还应该使用其他东西吗？

    let deltaX = player.position.x - monster.position.x
    let deltaY = player.position.y - monster.position.y
    let angle = atan2(deltaY, deltaX)

    monProjectile.physicsBody?.applyAngularImpulse(angle)

Answer 1

更新

查看您提供的代码后，我怀疑有两个问题：

1) 您正在指定一个我在您的项目中看不到的“射弹”图像。

2) 您正在尝试应用角脉冲（即旋转）而不是常规脉冲（即方向加速度）。

要解决第一个问题，请为您的弹丸添加图像。要解决第二个问题，请考虑使用 applyImpulse() 和 CGVector。

原答案

在我的脑海中，有几件事可能会导致这种情况：

1) 你施加了多大的冲动？打印出值并查看您使用的数字类型。

2) 你的射弹在怪物创建时会与怪物重叠吗？如果是这样，它可能会发生碰撞并卡住。

3) 弹丸是否有可能与其他节点完全碰撞，例如背景图片？

您应该考虑将您的SKView 的showsPhysics 设置为true，这样您就可以更清楚地看到发生了什么。

Answer 2

func makeShoot() {
    let Shoot:ShootClass = ShootClass.init()
    Shoot.physicsBody = SKPhysicsBody(texture: Shoot.texture!,
                                     size: Shoot.texture!.size())
    Shoot.position = (self.Shoot?.position)!
    Shoot.currentPosition = (self.Shoot?.position)!
    Shoot.physicsBody?.isDynamic = true
    Shoot.physicsBody?.allowsRotation = false
    Shoot.physicsBody?.affectedByGravity = false
    Shoot.physicsBody?.friction = 0
    Shoot.physicsBody?.restitution = 1
    Shoot.physicsBody?.mass = 1
    Shoot.physicsBody?.linearDamping = 0.0
    Shoot.physicsBody?.angularDamping = 0.0
    Shoot.physicsBody?.categoryBitMask = ShootCategory
    Shoot.physicsBody?.collisionBitMask = BorderCategory
    Shoot.physicsBody?.contactTestBitMask = BorderCategory

    PlayingView.addChild(Shoot);

    Shoot.physicsBody?.applyImpulse(CGVector(dx: 100, dy: 100))

    self.moveNodeToLocation(Shoot: Shoot)
}



override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    let curTouch = touches.first!
    let curPoint = curTouch.location(in: self)
    if ((curPoint.x > 103.5 && curPoint.y > 50.0) || (curPoint.x < 840.0 && curPoint.y > 50.0)) {
        StartingPoint = touches.first?.location(in: self)
        direction?.isHidden = false
        direction?.setScale(0.50)
        FirstTouchLocater = SKSpriteNode(imageNamed: "ic_Shootz");
        FirstTouchLocater.position = curPoint
        FirstTouchLocater.alpha = 0.5
        self.addChild(FirstTouchLocater);

    }
    else{
        self.direction?.isHidden = true
    }
}

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {

    let point:CGPoint = (touches.first?.location(in: self))!

    if point.y < 40 {
        return
    }

    if !(isTouch!) {
        isTouch = true
    }


    let dy:CGFloat = StartingPoint!.y - point.y

    let size:CGFloat = dy*10/self.frame.height

    if size < 2 && size > 0.50 {
        direction?.setScale(size)
    }
     print("size ======> \(size)")




    let curTouch = touches.first!
    let curPoint = curTouch.location(in: self)

    if (curPoint.x <= ((StartingPoint?.x)! + 20.0)) &&  ((curPoint.x + 20.0) >= (StartingPoint?.x)!) && (curPoint.y <= ((StartingPoint?.y)! + 20.0)) &&  ((curPoint.y + 20.0) >= (StartingPoint?.y)!){
        self.direction?.isHidden = true
        FirstTouchLocater?.isHidden = true
    }
    else if ((curPoint.x > 103.5 && curPoint.y > 50.0) || (curPoint.x < 840.0 && curPoint.y > 50.0)) {
        let deltaX = (self.direction?.position.x)! - curPoint.x
        let deltaY = (self.direction?.position.y)! - curPoint.y
        let angle = atan2(deltaY, deltaX)

        let DegreesToRadians = CGFloat.pi / 180

        self.direction?.zRotation = angle + 90 * DegreesToRadians
        self.direction?.isHidden = false
        FirstTouchLocater?.isHidden = false
    }
    else{
        self.direction?.isHidden = true
        FirstTouchLocater?.isHidden = true
    }
}

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    if direction?.isHidden == false {
        FirstTouchLocater.removeFromParent()
        direction?.isHidden = true
        direction?.setScale(0.1)
        if timeThrow == nil && isTouch!
        {
            isTouch = false
            counterY = 0;

            let touch = touches.first
            let touchLocation = touch?.location(in: self)
            lastTouch = touchLocation
            lastTouch1 = touchLocation

            ShootThrow = 2

            timeThrow = Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(self.loadScreen), userInfo: nil, repeats: true)
        }
    }
}

func moveNodeToLocation(Shoot:SKSpriteNode) {
    let dx = (lastTouch?.x)! - Shoot.position.x
    let dy = (lastTouch?.y)! - Shoot.position.y

    let speed1:CGFloat = 424
    let hypo = hypot(dx, dy)

    let newX = (speed1 * dx) / hypo
    let newY = (speed1 * dy) / hypo
    Shoot.physicsBody?.velocity = CGVector(dx:newX, dy: newY)

}

}