我想无限期地旋转一个精灵，每次点击按钮，我都希望精灵以相反的方向旋转（从顺时针到逆时针等来回旋转等。
以下是我的代码：
class GameScene: SKScene {
var center = SKSpriteNode()
var bg = SKSpriteNode()
var bigCircle = SKSpriteNode()
let counterClockwise = SKAction.rotateByAngle(CGFloat(3.14), duration:1)
let clockwise = SKAction.rotateByAngle(CGFloat(-3.14), duration:1)
var spin = SKAction()
override func didMoveToView(view: SKView) {
//Background
var bgTexture = SKTexture(imageNamed: "images/bg.png")
bg = SKSpriteNode(texture:bgTexture)
bg.position = CGPoint(x: CGRectGetMidX(self.frame), y: CGRectGetMidY(self.frame))
self.addChild(center)
//Center Circle
var bigCircleTexture = SKTexture(imageNamed: "images/bigCircle.png")
bigCircle = SKSpriteNode(texture:bigCircleTexture)
bigCircle.position = CGPoint(x: CGRectGetMidX(self.frame), y: CGRectGetMidY(self.frame))
self.addChild(bigCircle)
//Center Triangle
var centerTexture = SKTexture(imageNamed: "images/center.png")
center = SKSpriteNode(texture:centerTexture)
center.position = CGPoint(x: CGRectGetMidX(self.frame), y: CGRectGetMidY(self.frame))
self.addChild(center)
spin = clockwise
center.runAction(SKAction.repeatActionForever(spin))
}
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
/* Called when a touch begins */
if spin == clockwise {
spin = counterClockwise
}
else {
spin = clockwise
}
center.runAction(SKAction.repeatActionForever(spin))
}
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
}
}
答案 0 :(得分：1)
您的问题是，您没有删除尝试轮换SKAction的旧版SKSpriteNode。要做到这一点，你需要跟踪你的精灵旋转的方式。如果我要实现这个，我会继承SKSpriteNode，如下：
class RotatingSprite: SKSpriteNode {
// This is used to keep track of which way the sprite is rotating.
enum Direction {
case Left, Right
mutating func inverse() {
switch self {
case .Left : self = .Right
case .Right: self = .Left
}
}
}
// These names will be the keys used when running an action.
// This will allow you to stop the rotate-left or rotate-right actions.
static let rotateLeftName = "RotateLeftAction"
static let rotateRightName = "RotateRightAction"
var rotationDirection: Direction? {
didSet {
if let r = rotationDirection {
switch r {
// Checks the sprite isn't already rotating to the left.
// If it isn't, make the sprite rotate to the left.
case .Left where oldValue != .Left:
rotateLeft()
case .Right where oldValue != .Right:
rotateRight()
default:
break
}
}
}
}
private func rotateLeft() {
// Remove the action rotating the sprite to the right.
self.removeActionForKey(RotatingSprite.rotateRightName)
// And start the action rotating the sprite to the left.
let rotateAction = SKAction.rotateByAngle(-CGFloat(M_PI), duration: 1.0)
self.runAction(SKAction.repeatActionForever(rotateAction), withKey: RotatingSprite.rotateLeftName)
}
private func rotateRight() {
self.removeActionForKey(RotatingSprite.rotateLeftName)
let rotateAction = SKAction.rotateByAngle(CGFloat(M_PI), duration: 1.0)
self.runAction(SKAction.repeatActionForever(rotateAction), withKey: RotatingSprite.rotateRightName)
}
}
现在你可以这样使用RotatingSprite：
class GameScene: SKScene {
let rotatingSprite = RotatingSprite(texture:bgTexture)
override func didMoveToView(view: SKView) {
rotatingSprite.position = CGPoint(x: frame.midX, y: frame.midY)
self.addChild(rotatingSprite)
}
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
// If the sprite isn't turning you've got to set it off.
if rotatingSprite.rotationDirection == nil {
rotatingSprite.rotationDirection = .Left
// If it is turning, change its direction.
} else {
rotatingSprite.rotationDirection!.inverse()
}
}
}
希望有所帮助！
答案 1 :(得分：1)
实现这一目标非常容易。试试这个，
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
/* Called when a touch begins */
[sprite removeAllActions];
SKAction *action;
if (isClockWise)
{
action = [SKAction rotateByAngle:M_PI duration:1];
}
else
{
action = [SKAction rotateByAngle:-M_PI duration:1];
}
isClockWise = !isClockWise;
[sprite runAction:[SKAction repeatActionForever:action]];
}
其中精灵是SKSpriteNode并根据您的初始移动方向将isClockWise启动为是或否。
答案 2 :(得分：0)
执行此操作的快速而肮脏的方法如下：
import SpriteKit
class GameScene: SKScene {
var center = SKSpriteNode()
var bg = SKSpriteNode()
var bigCircle = SKSpriteNode()
let counterClockwise = SKAction.rotateByAngle(CGFloat(3.14), duration:1)
let clockwise = SKAction.rotateByAngle(CGFloat(-3.14), duration:1)
var spin = SKAction()
// this is used to identify which direction we are going in. When we change it spin is changed as well
var isClockwise: Bool = true {
didSet {
if isClockwise {
spin = clockwise
} else {
spin = counterClockwise
}
}
}
let actionKey = "spin" // this is used to identify the SKAction
override func didMoveToView(view: SKView) {
//Background
var bgTexture = SKTexture(imageNamed: "images/bg.png")
bg = SKSpriteNode(texture:bgTexture)
bg.position = CGPoint(x: CGRectGetMidX(self.frame), y: CGRectGetMidY(self.frame))
self.addChild(center)
//Center Circle
var bigCircleTexture = SKTexture(imageNamed: "images/bigCircle.png")
bigCircle = SKSpriteNode(texture:bigCircleTexture)
bigCircle.position = CGPoint(x: CGRectGetMidX(self.frame), y: CGRectGetMidY(self.frame))
self.addChild(bigCircle)
//Center Triangle
var centerTexture = SKTexture(imageNamed: "images/center.png")
center = SKSpriteNode(texture:centerTexture)
center.position = CGPoint(x: CGRectGetMidX(self.frame), y: CGRectGetMidY(self.frame))
self.addChild(center)
isClockwise = true // set the initial direction to clockwise
center.runAction(SKAction.repeatActionForever(spin), withKey: actionKey)
}
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
// remove the existing spin action
center.removeActionForKey(actionKey)
// reset the direction (this will automatically switch the SKAction)
isClockwise = !isClockwise
center.runAction(SKAction.repeatActionForever(spin), withKey: actionKey)
}
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
}
}
您需要在应用新操作之前删除操作 - 您可以通过调用runAction（action：，withKey :)来有选择地删除操作。这使您能够使用相同的键删除相同的操作。对于spin var声明，更改didSet的逻辑位于isClockwise。
答案 3 :(得分：0)
就像在每个if语句中放置center.removeAllActions一样简单，以确保当方向应该被更改时，精灵当前没有移动。