我计算了UIGestureRecognizer的速度，我想在SpriteKit中将其用作Physicsbody的速度。
我该怎么做，因为速度是在触摸开始和触摸结束方法中计算的，而我的物理身体被包裹在向上滑动和向下滑动等函数中，无法访问速度变量？
这是我的代码：
class GameScene: SKScene, SKPhysicsContactDelegate, SKViewDelegate, UIGestureRecognizerDelegate, UIViewControllerTransitioningDelegate {
var Kite = SKSpriteNode(imageNamed: "ASC_8025_large.jpg")
@objc let minusButton = SKSpriteNode(imageNamed: "minus.jpg")
@objc let plusButton = SKSpriteNode(imageNamed: "plus.png")
//override init(Kite: SKSpriteNode) {
//For long Long press gesture to work
let longPressGestureRecPlus = UILongPressGestureRecognizer()
let longPressGestureRecMinus = UILongPressGestureRecognizer(target: self, action: #selector(longPressed(press:)))
//First we declare all of our Gestures...
//swipes
let swipeRightRec = UISwipeGestureRecognizer()
let swipeLeftRec = UISwipeGestureRecognizer()
let swipeUpRec = UISwipeGestureRecognizer()
let swipeDownRec = UISwipeGestureRecognizer()
//rotate
let rotateRec = UIRotationGestureRecognizer()
//taps
let tapRec = UITapGestureRecognizer()
let tapRec2 = UITapGestureRecognizer()
override func didMove(to view: SKView) {
// Get label node from scene and store it for use later
Kite.size = CGSize(width: 40.0, height: 40.0)
Kite.position = CGPoint(x: frame.midX, y: frame.midY)
plusButton.size = CGSize(width: 30.0, height: 30.0)
plusButton.position = CGPoint(x: frame.midX, y: frame.minY + 20.0)
plusButton.name = "plusButton"
//plusButton.isUserInteractionEnabled = true
addChild(Kite)
addChild(plusButton)
swipeRightRec.addTarget(self, action: #selector(GameScene.swipedRight) )
swipeRightRec.direction = .right
self.view!.addGestureRecognizer(swipeRightRec)
swipeLeftRec.addTarget(self, action: #selector(GameScene.swipedLeft) )
swipeLeftRec.direction = .left
self.view!.addGestureRecognizer(swipeLeftRec)
swipeUpRec.addTarget(self, action: #selector(GameScene.swipedUp) )
swipeUpRec.direction = .up
self.view!.addGestureRecognizer(swipeUpRec)
swipeDownRec.addTarget(self, action: #selector(GameScene.swipedDown) )
swipeDownRec.direction = .down
self.view!.addGestureRecognizer(swipeDownRec)
//notice the function this calls has (_:) after it because we are passing in info about the gesture itself (the sender)
rotateRec.addTarget(self, action: #selector (GameScene.rotatedView (_:) ))
self.view!.addGestureRecognizer(rotateRec)
// again notice (_:), we'll need this to find out where the tap occurred.
tapRec.addTarget(self, action:#selector(GameScene.tappedView(_:) ))
tapRec.numberOfTouchesRequired = 1
tapRec.numberOfTapsRequired = 1
self.view!.addGestureRecognizer(tapRec)
tapRec2.addTarget(self, action:#selector(GameScene.tappedView2(_:) ))
tapRec2.numberOfTouchesRequired = 1
tapRec2.numberOfTapsRequired = 2 //2 taps instead of 1 this time
self.view!.addGestureRecognizer(tapRec2)
longPressGestureRecPlus.addTarget(self, action: #selector(longPressed(press:)))
longPressGestureRecPlus.minimumPressDuration = 2.0
self.view?.addGestureRecognizer(longPressGestureRecPlus)
}
//the functions that get called when swiping...
@objc func swipedRight() {
print("Right")
Kite.physicsBody?.velocity = CGVector(dx: 60, dy: 60)
//Tilts the Kite towards Right
let tiltRight = SKAction.rotate(toAngle: -1.00, duration: 0.1)
Kite.run(tiltRight)
}
@objc func swipedLeft() {
Kite.physicsBody?.velocity = CGVector(dx: -60, dy: 60)
//Tilts the Kite towards Right
let tiltLeft = SKAction.rotate(toAngle: 1.00, duration: 0.1)
Kite.run(tiltLeft)
print("Left")
}
@objc func swipedUp() {
Kite.physicsBody?.velocity = CGVector(dx: 60, dy: 60)
//Straightens the Kite
let straightens = SKAction.rotate(toAngle: 0.00, duration: 0.1)
Kite.run(straightens)
print("Up")
}
@objc func swipedDown() {
Kite.physicsBody?.velocity = CGVector(dx: 0, dy: -60)
print("Down")
}
// what gets called when there's a single tap...
//notice the sender is a parameter. This is why we added (_:) that part to the selector earlier
@objc func tappedView(_ sender:UITapGestureRecognizer) {
let point:CGPoint = sender.location(in: self.view)
print("Single tap")
print(point)
}
// what gets called when there's a double tap...
//notice the sender is a parameter. This is why we added (_:) that part to the selector earlier
@objc func tappedView2(_ sender:UITapGestureRecognizer) {
let point:CGPoint = sender.location(in: self.view)
print("Double tap")
print(point)
}
//what gets called when there's a rotation gesture
//notice the sender is a parameter. This is why we added (_:) that part to the selector earlier
@objc func rotatedView(_ sender:UIRotationGestureRecognizer) {
if (sender.state == .began) {
print("rotation began")
}
if (sender.state == .changed) {
print("rotation changed")
//you could easily make any sprite's rotation equal this amount like so...
//thePlayer.zRotation = -sender.rotation
//convert rotation to degrees...
let rotateAmount = Measurement(value: Double(sender.rotation), unit: UnitAngle.radians).converted(to: .degrees).value
print("(rotateAmount) degreess" )
}
if (sender.state == .ended) {
print("rotation ended")
}
}
func removeAllGestures(){
//if you need to remove all gesture recognizers with Swift you can do this....
for gesture in (self.view?.gestureRecognizers)! {
self.view?.removeGestureRecognizer(gesture)
}
//this is good to do before a SKScene transitions to another SKScene.
}
func removeAGesture()
{
//To remove a single gesture you can use...
self.view?.removeGestureRecognizer(swipeUpRec)
}
//Fix the gesture recognizing the plusButton
@objc func longPressed(press: UILongPressGestureRecognizer) {
if press.state == .began {
isUserInteractionEnabled = true
let positionInScene = press.location(in: self.view)
let touchedNode = self.atPoint(positionInScene)
plusButton.name = "plusButton"
Kite.physicsBody?.velocity = CGVector(dx: 0, dy: 60.0*3)
print("Pressed on the screen")
if let name = touchedNode.name {
if name == "plusButton" {
print("LONG TAPPED")
}
}
}
}
var start: CGPoint?
var startTime: TimeInterval?
var taps = 0
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
print("Began")
Kite.physicsBody = SKPhysicsBody(rectangleOf: Kite.size)
Kite.physicsBody?.affectedByGravity = false
//Kite.physicsBody?.velocity = CGVector(dx: 0, dy: 0)
Kite.physicsBody?.applyImpulse(CGVector(dx: 0, dy: 5))
plusButton.name = "plusButton"
plusButton.isUserInteractionEnabled = false
//We figure how to interact with BUTTON in Spritekit
let touch = touches.first
let positionInScene = touch!.location(in: self)
let touchedNode = self.atPoint(positionInScene)
if let name = touchedNode.name {
if name == "plusButton" {
taps += 1
Kite.size = CGSize(width: 200, height: 200)
print("tapped")
print("Taps", taps)
}
}
for touch in touches {
let location:CGPoint = touch.location(in: self.view!)
start = location
startTime = touch.timestamp
}
}
override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
print("Ended")
//Calculating Speed of the Gestures
for touch in touches {
let location:CGPoint = touch.location(in: self.view!)
var dx:CGFloat = location.x - start!.x;
var dy:CGFloat = location.y - start!.y;
var magnitude:CGFloat = sqrt(dx*dx+dy*dy)
//Calculate Time
var dt:CGFloat = CGFloat(touch.timestamp - startTime!)
//Speed = Distance / Time
var speed:CGFloat = magnitude / dt
var speedX:CGFloat = dx/dt
var speedY:CGFloat = dy/dt
print("SpeedY", speedX)
print("SpeedY", speedY)
}
}
因此从 dx 和 dy 等向量计算速度是
let speed = sqrtf(Float(pow(dx!, 2) + pow(dy!, 2)))
因此，如果要将速度作为速度应用于对象，则至少需要一个方向。
let newDx = 0 // means in no x direction
// next you can change the formula to your new dy to match the given speed
let newDy = sqrtf(pow(speed, 2) - Float(pow(newDx, 2)))
yourNode.physicsBody?.velocity = CGVector(dx: newDx, dy: CGFloat(newDy))