用 SKScene 和 SKActions 替换 CALayer 和 CABasicAnimation
replacing CALayer and CABasicAnimation with SKScene and SKActions
我正在尝试在 Metaballs 上重组此 Github Swift project，以便圆圈由 SKShapeNodes 表示，这些圆圈由 SKActions 而不是 CABasicAnimation 移动。
我对 viewController 中出现的各种 Metaball 参数（handleLenRate、Spacing 等）不感兴趣。我基本上希望能够使用 SKActions 为动画指定开始和结束位置。
我不确定如何实现这一点，尤其是如何用 SKShapeNode 的 SKActions 替换下面的 startAnimation 函数：
func startAnimation() {
let loadingLayer = self.layer as! DBMetaballLoadingLayer
loadingAnimation = CABasicAnimation(keyPath: "movingBallCenterX")
loadingAnimation!.duration = 2.5
loadingAnimation!.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
loadingAnimation!.fromValue = NSValue(CGPoint:fromPoint)
loadingAnimation!.toValue = NSValue(CGPoint: toPoint)
loadingAnimation!.repeatCount = Float.infinity
loadingAnimation!.autoreverses = true
loadingLayer.addAnimation(loadingAnimation!, forKey: "loading")
}
请在下方查看我能够执行的操作：
MBCircle class:
struct MBCircle {
var center: CGPoint = CGPointZero
var radius: CGFloat = 0.0
var frame: CGRect {
get {
return CGRect(x: center.x - radius, y: center.y - radius, width: 2 * radius, height: 2 * radius)
}
}
}
struct DefaultConfig {
static let radius: CGFloat = 15.0
static let mv: CGFloat = 0.6
static let maxDistance: CGFloat = 10 * DefaultConfig.radius
static let handleLenRate: CGFloat = 2.0
static let spacing: CGFloat = 160.0
}
GameScene class（代表DBMetaballLoadingLayer和DBMetaballLoadingView）：
class GameScene: SKScene {
private let MOVE_BALL_SCALE_RATE: CGFloat = 0.75
private let ITEM_COUNT = 2
private let SCALE_RATE: CGFloat = 1.0//0.3
private var circlePaths = [MBCircle]()
var radius: CGFloat = DefaultConfig.radius
var maxLength: CGFloat {
get {
return (radius * 4 + spacing) * CGFloat(ITEM_COUNT)
}
}
var maxDistance: CGFloat = DefaultConfig.maxDistance
var mv: CGFloat = DefaultConfig.mv
var spacing: CGFloat = DefaultConfig.spacing {
didSet {
_adjustSpacing(spacing)
}
}
var handleLenRate: CGFloat = DefaultConfig.handleLenRate
var movingBallCenterX : CGFloat = 0.0 {
didSet {
if (circlePaths.count > 0) {
circlePaths[0].center = CGPoint(x: movingBallCenterX, y: circlePaths[0].center.y)
}
}
}
func _generalInit() {
circlePaths = Array(0..<ITEM_COUNT).map { i in
var circlePath = MBCircle()
circlePath.center = CGPoint(x: (radius * 10 + spacing) * CGFloat(i), y: radius * (1.0 + SCALE_RATE))
circlePath.radius = i == 0 ? radius * MOVE_BALL_SCALE_RATE : radius
circlePath.sprite = SKShapeNode(circleOfRadius: circlePath.radius)
circlePath.sprite?.position = circlePath.center
circlePath.sprite?.fillColor = UIColor.blueColor()
addChild(circlePath.sprite!)
return circlePath
}
}
func _adjustSpacing(spacing: CGFloat) {
if (ITEM_COUNT > 1 && circlePaths.count > 1) {
for i in 1..<ITEM_COUNT {
var circlePath = circlePaths[i]
circlePath.center = CGPoint(x: (radius*2 + spacing) * CGFloat(i), y: radius * (1.0 + SCALE_RATE))
}
}
}
func _renderPath(path: UIBezierPath) {
var shapeNode = SKShapeNode()
shapeNode.path = path.CGPath
shapeNode.fillColor = UIColor.blueColor()
addChild(shapeNode)
}
func _metaball(j: Int, i: Int, v: CGFloat, handeLenRate: CGFloat, maxDistance: CGFloat) {
let circle1 = circlePaths[i]
let circle2 = circlePaths[j]
let center1 = circle1.center
let center2 = circle2.center
let d = center1.distance(center2)
var radius1 = circle1.radius
var radius2 = circle2.radius
if (d > maxDistance) {
_renderPath(UIBezierPath(ovalInRect: circle2.frame))
} else {
let scale2 = 1 + SCALE_RATE * (1 - d / maxDistance)
radius2 *= scale2
_renderPath(UIBezierPath(ovalInRect: CGRect(x: circle2.center.x - radius2, y: circle2.center.y - radius2, width: 2 * radius2, height: 2 * radius2)))
}
if (radius1 == 0 || radius2 == 0) {
return
}
var u1: CGFloat = 0.0
var u2: CGFloat = 0.0
if (d > maxDistance || d <= abs(radius1 - radius2)) {
return
} else if (d < radius1 + radius2) {
u1 = acos((radius1 * radius1 + d * d - radius2 * radius2) / (2 * radius1 * d))
u2 = acos((radius2 * radius2 + d * d - radius1 * radius1) / (2 * radius2 * d))
} else {
u1 = 0.0
u2 = 0.0
}
let angle1 = center1.angleBetween(center2)
let angle2 = acos((radius1 - radius2) / d)
let angle1a = angle1 + u1 + (angle2 - u1) * v
let angle1b = angle1 - u1 - (angle2 - u1) * v
let angle2a = angle1 + CGFloat(M_PI) - u2 - (CGFloat(M_PI) - u2 - angle2) * v
let angle2b = angle1 - CGFloat(M_PI) + u2 + (CGFloat(M_PI) - u2 - angle2) * v
let p1a = center1.point(radians: angle1a, withLength: radius1)
let p1b = center1.point(radians: angle1b, withLength: radius1)
let p2a = center2.point(radians: angle2a, withLength: radius2)
let p2b = center2.point(radians: angle2b, withLength: radius2)
let totalRadius = radius1 + radius2
var d2 = min(v * handeLenRate, p1a.minus(p2a).length() / totalRadius)
d2 *= min(1, d * 2 / totalRadius)
radius1 *= d2
radius2 *= d2
let cp1a = p1a.point(radians: angle1a - CGFloat(M_PI_2), withLength: radius1)
let cp2a = p2a.point(radians: angle2a + CGFloat(M_PI_2), withLength: radius2)
let cp2b = p2b.point(radians: angle2b - CGFloat(M_PI_2), withLength: radius2)
let cp1b = p1b.point(radians: angle1b + CGFloat(M_PI_2), withLength: radius1)
let pathJoinedCircles = UIBezierPath()
pathJoinedCircles.moveToPoint(p1a)
pathJoinedCircles.addCurveToPoint(p2a, controlPoint1: cp1a, controlPoint2: cp2a)
pathJoinedCircles.addLineToPoint(p2b)
pathJoinedCircles.addCurveToPoint(p1b, controlPoint1: cp2b, controlPoint2: cp1b)
pathJoinedCircles.addLineToPoint(p1a)
pathJoinedCircles.closePath()
_renderPath(pathJoinedCircles)
}
func startAnimation() {
}
override func didMoveToView(view: SKView) {
_generalInit()
}
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
}
}
我没有对CGPointExtensionclass进行任何更改。
更新
我仍在努力获得变形球效果，这是我目前根据 Alessandro Ornano 的建议取得的进展：
import SpriteKit
extension CGPoint {
func distance(point: CGPoint) -> CGFloat {
let dx = point.x - self.x
let dy = point.y - self.y
return sqrt(dx * dx + dy * dy)
}
func angleBetween(point: CGPoint) -> CGFloat {
return atan2(point.y - self.y, point.x - self.x)
}
func point(radians radians: CGFloat, withLength length: CGFloat) -> CGPoint {
return CGPoint(x: self.x + length * cos(radians), y: self.y + length * sin(radians))
}
func minus(point: CGPoint) -> CGPoint {
return CGPoint(x: self.x - point.x, y: self.y - point.y)
}
func length() -> CGFloat {
return sqrt(self.x * self.x + self.y + self.y)
}
}
class GameScene: SKScene {
var dBCircle : SKShapeNode!
let radiusDBCircle: CGFloat = 10
let radiusBall: CGFloat = 15
var balls = [SKShapeNode]()
var distanceBtwBalls : CGFloat = 15
private let SCALE_RATE: CGFloat = 0.3
override func didMoveToView(view: SKView) {
// Some parameters
let strokeColor = SKColor.orangeColor()
let dBHeight = CGRectGetMaxY(self.frame)-84 // 64 navigationController height + 20 reasonable distance
let dBStartX = CGRectGetMidX(self.frame)-160 // extreme left
let dBStopX = CGRectGetMidX(self.frame)+160 // extreme right
let dBWidth = dBStopX - dBStartX
let totalBalls = 7 // first and last will be hidden
let ballArea = dBWidth / CGFloat(totalBalls-1)
distanceBtwBalls = ((ballArea-(radiusBall*2))+radiusBall*2)
// Create dbCircle
dBCircle = SKShapeNode.init(circleOfRadius: radiusDBCircle)
dBCircle.position = CGPointMake(CGRectGetMidX(self.frame), dBHeight)
dBCircle.strokeColor = strokeColor
dBCircle.name = "dBCircle"
dBCircle.fillColor = UIColor.clearColor()
addChild(dBCircle)
// Make static balls
for i in 0..<totalBalls {
let ball = SKShapeNode.init(circleOfRadius: radiusBall)
ball.position = CGPointMake(dBStartX+(distanceBtwBalls*CGFloat(i)), dBHeight)
ball.strokeColor = strokeColor
ball.name = "ball"
ball.fillColor = UIColor.clearColor()
balls.append(ball)
if i == 0 || i == totalBalls-1 {
ball.hidden = true
}
addChild(ball)
}
mediaTimingFunctionEaseInEaseOutEmulate(dBCircle,dBStartX: dBStartX,dBStopX: dBStopX)
}
func mediaTimingFunctionEaseInEaseOutEmulate(node:SKShapeNode,dBStartX:CGFloat,dBStopX:CGFloat) {
let actionMoveLeft = SKAction.moveToX(dBStartX, duration:1.7)
actionMoveLeft.timingMode = SKActionTimingMode.EaseInEaseOut
let actionMoveRight = SKAction.moveToX(dBStopX, duration:1.7)
actionMoveRight.timingMode = SKActionTimingMode.EaseInEaseOut
node.runAction(SKAction.repeatActionForever(SKAction.sequence([actionMoveLeft,actionMoveRight])))
}
override func update(currentTime: NSTimeInterval) {
var i = 0
self.enumerateChildNodesWithName("ball") {
node, stop in
let ball = node as! SKShapeNode
if CGRectContainsRect(ball.frame, self.dBCircle.frame) {
if (ball.actionForKey("zoom") == nil) {
let zoomIn = SKAction.scaleTo(1.5, duration: 0.25)
let zoomOut = SKAction.scaleTo(1.0, duration: 0.25)
let seq = SKAction.sequence([zoomIn,zoomOut])
ball.runAction(seq,withKey: "zoom")
}
}
i += 1
}
movingBeziers()
}
func _renderPath(path: UIBezierPath) {
let shapeNode = SKShapeNode(path: path.CGPath)
shapeNode.fillColor = UIColor.blueColor()
addChild(shapeNode)
}
func movingBeziers() {
_renderPath(UIBezierPath(ovalInRect: dBCircle.frame))
for j in 1..<balls.count {
self.latestTestMetaball(j, circleShape: dBCircle, v: 0.6, handleLenRate: 2.0, maxDistance: self.distanceBtwBalls)
}
}
func latestTestMetaball (j: Int, circleShape: SKShapeNode, v: CGFloat, handleLenRate: CGFloat, maxDistance: CGFloat) {
let circle1 = circleShape
let circle2 = balls[j]
let center1 = circle1.position
let center2 = circle2.position
let d = center1.distance(center2)
var radius1 = circle1.frame.width
var radius2 = circle2.frame.width
var u1: CGFloat = 0.0
var u2: CGFloat = 0.0
if (d > maxDistance || d <= abs(radius1 - radius2)) {
return
} else if (d < radius1 + radius2) {
u1 = acos((radius1 * radius1 + d * d - radius2 * radius2) / (2 * radius1 * d))
u2 = acos((radius2 * radius2 + d * d - radius1 * radius1) / (2 * radius2 * d))
} else {
u1 = 0.0
u2 = 0.0
}
let angle1 = center1.angleBetween(center2)
let angle2 = acos((radius1 - radius2) / d)
let angle1a = angle1 + u1 + (angle2 - u1) * v
let angle1b = angle1 - u1 - (angle2 - u1) * v
let angle2a = angle1 + CGFloat(M_PI) - u2 - (CGFloat(M_PI) - u2 - angle2) * v
let angle2b = angle1 - CGFloat(M_PI) + u2 + (CGFloat(M_PI) - u2 - angle2) * v
let p1a = center1.point(radians: angle1a, withLength: radius1)
let p1b = center1.point(radians: angle1b, withLength: radius1)
let p2a = center2.point(radians: angle2a, withLength: radius2)
let p2b = center2.point(radians: angle2b, withLength: radius2)
let totalRadius = radius1 + radius2
var d2 = min(v * handleLenRate, p1a.minus(p2a).length() / totalRadius)
d2 *= min(1, d * 2 / totalRadius)
radius1 *= d2
radius2 *= d2
let cp1a = p1a.point(radians: angle1a - CGFloat(M_PI_2), withLength: radius1)
let cp2a = p2a.point(radians: angle2a + CGFloat(M_PI_2), withLength: radius2)
let cp2b = p2b.point(radians: angle2b - CGFloat(M_PI_2), withLength: radius2)
let cp1b = p1b.point(radians: angle1b + CGFloat(M_PI_2), withLength: radius1)
let pathJoinedCircles = UIBezierPath()
pathJoinedCircles.moveToPoint(p1a)
pathJoinedCircles.addCurveToPoint(p2a, controlPoint1: cp1a, controlPoint2: cp2a)
pathJoinedCircles.addLineToPoint(p2b)
pathJoinedCircles.addCurveToPoint(p1b, controlPoint1: cp2b, controlPoint2: cp1b)
pathJoinedCircles.addLineToPoint(p1a)
pathJoinedCircles.closePath()
let shapeNode = SKShapeNode(path: pathJoinedCircles.CGPath)
shapeNode.fillColor = UIColor.blueColor()
addChild(shapeNode)
}
}
假设您的问题是如何使用节点和 SKAction 复制相同的行为，我相信这应该可以做到。
var shapeNode : SKNode?
func startAnimation(){
if let node = self.shapeNode {
//assume that we have a node initialized at some point and added to the scene at some x1,y1 coordinates
/// we define parameters for the animation
let positionToReach = CGPoint(x: 100, y: 100) /// some random position
let currentPosition = node.position /// we need the current position to be able to reverse the "animation"
let animationDuration = 2.5 //loadingAnimation!.duration = 2.5
/// we define which actions will be run for the node
let actionForward = SKAction.moveTo(positionToReach, duration: animationDuration)
let actionBackwards = SKAction.moveTo(currentPosition, duration: animationDuration)
// we needed two actions to simulate loadingAnimation!.autoreverses = true
/// we wrap the actions in a sequence of actions
let actionSequence = SKAction.sequence([actionForward, actionBackwards]) /// animations to repeat
/// we want to repeat the animation forever
let actionToRepeat = SKAction.repeatActionForever(actionSequence) ///loadingAnimation!.repeatCount = Float.infinity
/// showtime
node.runAction(actionToRepeat)
}
}
如果我需要更新任何部分，请告诉我，因为我还没有测试过它。您仍然需要使用您的实际值和对象。
我在回复时提到了How would I repeat an action forever in Swift?。
您可以使用 moveToX 和 timingMode parameter.
轻松实现这种动画
新 Swift 3 翻译在下面这个答案的末尾。
举个例子我用Xcode Sprite-Kit "Hello, World!"官方项目demo:
class GameScene: SKScene {
override func didMoveToView(view: SKView) {
/* Setup your scene here */
let myLabel = SKLabelNode(fontNamed:"Chalkduster")
myLabel.text = "Hello, World!"
myLabel.fontSize = 15
myLabel.position = CGPoint(x:CGRectGetMidX(self.frame), y:CGRectGetMidY(self.frame))
self.addChild(myLabel)
mediaTimingFunctionEaseInEaseOutEmulate(myLabel)
}
func mediaTimingFunctionEaseInEaseOutEmulate(node:SKLabelNode) {
let actionMoveLeft = SKAction.moveToX(CGRectGetMidX(self.frame)-100, duration:1.5)
actionMoveLeft.timingMode = SKActionTimingMode.EaseInEaseOut
let actionMoveRight = SKAction.moveToX(CGRectGetMidX(self.frame)+100, duration:1.5)
actionMoveRight.timingMode = SKActionTimingMode.EaseInEaseOut
node.runAction(SKAction.repeatActionForever(SKAction.sequence([actionMoveLeft,actionMoveRight])))
}
}
输出:
更新（这部分开始模拟静态球和动态球左右移动但没有metaball动画）
class GameScene: SKScene {
var dBCircle : SKShapeNode!
let radiusDBCircle: CGFloat = 10
let radiusBall: CGFloat = 15
private let SCALE_RATE: CGFloat = 0.3
override func didMoveToView(view: SKView) {
// Some parameters
let strokeColor = SKColor.orangeColor()
let dBHeight = CGRectGetMaxY(self.frame)-84 // 64 navigationController height + 20 reasonable distance
let dBStartX = CGRectGetMidX(self.frame)-160 // extreme left
let dBStopX = CGRectGetMidX(self.frame)+160 // extreme right
let dBWidth = dBStopX - dBStartX
let totalBalls = 7 // first and last will be hidden
let ballArea = dBWidth / CGFloat(totalBalls-1)
let distanceBtwBalls = ((ballArea-(radiusBall*2))+radiusBall*2)
// Create dbCircle
dBCircle = SKShapeNode.init(circleOfRadius: radiusDBCircle)
dBCircle.position = CGPointMake(CGRectGetMidX(self.frame), dBHeight)
dBCircle.strokeColor = strokeColor
dBCircle.name = "dBCircle"
dBCircle.fillColor = UIColor.clearColor()
addChild(dBCircle)
// Make static balls
for i in 0..<totalBalls {
let ball = SKShapeNode.init(circleOfRadius: radiusBall)
ball.position = CGPointMake(dBStartX+(distanceBtwBalls*CGFloat(i)), dBHeight)
ball.strokeColor = strokeColor
ball.name = "ball"
ball.fillColor = UIColor.clearColor()
if i == 0 || i == totalBalls-1 {
ball.hidden = true
}
addChild(ball)
}
mediaTimingFunctionEaseInEaseOutEmulate(dBCircle,dBStartX: dBStartX,dBStopX: dBStopX)
}
func mediaTimingFunctionEaseInEaseOutEmulate(node:SKShapeNode,dBStartX:CGFloat,dBStopX:CGFloat) {
let actionMoveLeft = SKAction.moveToX(dBStartX, duration:1.7)
actionMoveLeft.timingMode = SKActionTimingMode.EaseInEaseOut
let actionMoveRight = SKAction.moveToX(dBStopX, duration:1.7)
actionMoveRight.timingMode = SKActionTimingMode.EaseInEaseOut
node.runAction(SKAction.repeatActionForever(SKAction.sequence([actionMoveLeft,actionMoveRight])))
}
override func update(currentTime: NSTimeInterval) {
var i = 0
self.enumerateChildNodesWithName("ball") {
node, stop in
let ball = node as! SKShapeNode
if CGRectContainsRect(ball.frame, self.dBCircle.frame) {
if (ball.actionForKey("zoom") == nil) {
let zoomIn = SKAction.scaleTo(1.5, duration: 0.25)
let zoomOut = SKAction.scaleTo(1.0, duration: 0.25)
let seq = SKAction.sequence([zoomIn,zoomOut])
ball.runAction(seq,withKey: "zoom")
}
}
i += 1
}
}
}
新的元球动画更新:
终于实现了这个结果，我的目标是让它和原来的非常相似:
是否可以对时间进行一些变化（例如 zoomIn 或 zoomOut 时间值或 actionMoveLeft、actionMoveRight 时间值），这是代码：
import SpriteKit
class GameScene: SKScene {
var dBCircle : SKShapeNode!
let radiusDBCircle: CGFloat = 10
let radiusBall: CGFloat = 15
private let SCALE_RATE: CGFloat = 0.3
override func didMoveToView(view: SKView) {
// Some parameters
let strokeColor = SKColor.orangeColor()
let dBHeight = CGRectGetMaxY(self.frame)-84 // 64 navigationController height + 20 reasonable distance
let dBStartX = CGRectGetMidX(self.frame)-160 // extreme left
let dBStopX = CGRectGetMidX(self.frame)+160 // extreme right
let dBWidth = dBStopX - dBStartX
let totalBalls = 7 // first and last will be hidden
let ballArea = dBWidth / CGFloat(totalBalls-1)
let distanceBtwBalls = ((ballArea-(radiusBall*2))+radiusBall*2)
// Create dbCircle
dBCircle = SKShapeNode.init(circleOfRadius: radiusDBCircle)
dBCircle.position = CGPointMake(CGRectGetMidX(self.frame), dBHeight)
dBCircle.strokeColor = strokeColor
dBCircle.name = "dBCircle"
dBCircle.fillColor = UIColor.clearColor()
addChild(dBCircle)
// Make static balls
for i in 0..<totalBalls {
let ball = SKShapeNode.init(circleOfRadius: radiusBall)
ball.position = CGPointMake(dBStartX+(distanceBtwBalls*CGFloat(i)), dBHeight)
ball.strokeColor = strokeColor
ball.name = "ball"
ball.fillColor = UIColor.clearColor()
if i == 0 || i == totalBalls-1 {
ball.hidden = true
}
addChild(ball)
}
mediaTimingFunctionEaseInEaseOutEmulate(dBCircle,dBStartX: dBStartX,dBStopX: dBStopX)
}
func mediaTimingFunctionEaseInEaseOutEmulate(node:SKShapeNode,dBStartX:CGFloat,dBStopX:CGFloat) {
let actionMoveLeft = SKAction.moveToX(dBStartX, duration:2.5)
actionMoveLeft.timingMode = SKActionTimingMode.EaseInEaseOut
let actionMoveRight = SKAction.moveToX(dBStopX, duration:2.5)
actionMoveRight.timingMode = SKActionTimingMode.EaseInEaseOut
node.runAction(SKAction.repeatActionForever(SKAction.sequence([actionMoveLeft,actionMoveRight])))
}
//MARK: - _metaball original function
func _metaball(circle2:SKShapeNode, circle1:SKShapeNode, v: CGFloat, handeLenRate: CGFloat, maxDistance: CGFloat,vanishingTime : NSTimeInterval = 0.015) {
let center1 = circle1.position
let center2 = circle2.position
let d = center1.distance(center2)
var radius1 = radiusDBCircle
var radius2 = radiusBall
if (radius1 == 0 || radius2 == 0) {
return
}
var u1: CGFloat = 0.0
var u2: CGFloat = 0.0
if (d > maxDistance || d <= abs(radius1 - radius2)) {
return
} else if (d < radius1 + radius2) {
u1 = acos((radius1 * radius1 + d * d - radius2 * radius2) / (2 * radius1 * d))
u2 = acos((radius2 * radius2 + d * d - radius1 * radius1) / (2 * radius2 * d))
} else {
u1 = 0.0
u2 = 0.0
}
let angle1 = center1.angleBetween(center2)
let angle2 = acos((radius1 - radius2) / d)
let angle1a = angle1 + u1 + (angle2 - u1) * v
let angle1b = angle1 - u1 - (angle2 - u1) * v
let angle2a = angle1 + CGFloat(M_PI) - u2 - (CGFloat(M_PI) - u2 - angle2) * v
let angle2b = angle1 - CGFloat(M_PI) + u2 + (CGFloat(M_PI) - u2 - angle2) * v
let p1a = center1.point(radians: angle1a, withLength: radius1)
let p1b = center1.point(radians: angle1b, withLength: radius1)
let p2a = center2.point(radians: angle2a, withLength: radius2)
let p2b = center2.point(radians: angle2b, withLength: radius2)
let totalRadius = radius1 + radius2
var d2 = min(v * handeLenRate, p1a.minus(p2a).length() / totalRadius)
d2 *= min(1, d * 2 / totalRadius)
radius1 *= d2
radius2 *= d2
let cp1a = p1a.point(radians: angle1a - CGFloat(M_PI_2), withLength: radius1)
let cp2a = p2a.point(radians: angle2a + CGFloat(M_PI_2), withLength: radius2)
let cp2b = p2b.point(radians: angle2b - CGFloat(M_PI_2), withLength: radius2)
let cp1b = p1b.point(radians: angle1b + CGFloat(M_PI_2), withLength: radius1)
let pathJoinedCircles = UIBezierPath()
pathJoinedCircles.moveToPoint(p1a)
pathJoinedCircles.addCurveToPoint(p2a, controlPoint1: cp1a, controlPoint2: cp2a)
pathJoinedCircles.addLineToPoint(p2b)
pathJoinedCircles.addCurveToPoint(p1b, controlPoint1: cp2b, controlPoint2: cp1b)
pathJoinedCircles.addLineToPoint(p1a)
pathJoinedCircles.closePath()
let shapeNode = SKShapeNode(path: pathJoinedCircles.CGPath)
shapeNode.strokeColor = SKColor.orangeColor()
shapeNode.fillColor = UIColor.clearColor()
addChild(shapeNode)
let wait = SKAction.waitForDuration(vanishingTime)
self.runAction(wait,completion: {
shapeNode.removeFromParent()
})
}
override func update(currentTime: NSTimeInterval) {
var i = 0
self.enumerateChildNodesWithName("ball") {
node, stop in
let ball = node as! SKShapeNode
let enlargeFrame = CGRectMake(ball.frame.origin.x-self.radiusBall*3,ball.frame.origin.y,ball.frame.width+(self.radiusBall*6),ball.frame.height)
if CGRectContainsRect(enlargeFrame, self.dBCircle.frame) {
if (ball.actionForKey("zoom") == nil) {
let zoomIn = SKAction.scaleTo(1.5, duration: 0.25)
zoomIn.timingMode = SKActionTimingMode.EaseInEaseOut
let zoomOut = SKAction.scaleTo(1.0, duration: 0.25)
let wait = SKAction.waitForDuration(0.8)
let seq = SKAction.sequence([zoomIn,zoomOut,wait])
ball.runAction(seq,withKey: "zoom")
}
}
self._metaball(ball, circle1: self.dBCircle, v: 0.6, handeLenRate: 2.0, maxDistance: 4 * self.radiusBall)
i += 1
}
}
}
//MARK: - Extensions
extension CGPoint {
func distance(point: CGPoint) -> CGFloat {
let dx = point.x - self.x
let dy = point.y - self.y
return sqrt(dx * dx + dy * dy)
}
func angleBetween(point: CGPoint) -> CGFloat {
return atan2(point.y - self.y, point.x - self.x)
}
func point(radians radians: CGFloat, withLength length: CGFloat) -> CGPoint {
return CGPoint(x: self.x + length * cos(radians), y: self.y + length * sin(radians))
}
func minus(point: CGPoint) -> CGPoint {
return CGPoint(x: self.x - point.x, y: self.y - point.y)
}
func length() -> CGFloat {
return sqrt(self.x * self.x + self.y + self.y)
}
}
Swift 3:
（我用 maxDistance: 5 * self.radiusBall 对 maxDistance: 4 * self.radiusBall 做了一点改动，使其与原始版本更相似，但您可以根据需要进行更改）
import SpriteKit
class GameScene: SKScene {
var dBCircle : SKShapeNode!
let radiusDBCircle: CGFloat = 10
let radiusBall: CGFloat = 15
private let SCALE_RATE: CGFloat = 0.3
override func didMove(to view: SKView) {
let label = self.childNode(withName: "//helloLabel") as? SKLabelNode
label?.removeFromParent()
self.anchorPoint = CGPoint.zero
// Some parameters
let strokeColor = SKColor.orange
let dBHeight = self.frame.midY
let dBStartX = self.frame.midX-260 // extreme left
let dBStopX = self.frame.midX+260 // extreme right
let dBWidth = dBStopX - dBStartX
let totalBalls = 7 // first and last will be hidden
let ballArea = dBWidth / CGFloat(totalBalls-1)
let distanceBtwBalls = ((ballArea-(radiusBall*2))+radiusBall*2)
// Create dbCircle
dBCircle = SKShapeNode.init(circleOfRadius: radiusDBCircle)
dBCircle.position = CGPoint(x:self.frame.midX, y:dBHeight)
dBCircle.strokeColor = strokeColor
dBCircle.name = "dBCircle"
dBCircle.fillColor = UIColor.clear
addChild(dBCircle)
// Make static balls
for i in 0..<totalBalls {
let ball = SKShapeNode.init(circleOfRadius: radiusBall)
ball.position = CGPoint(x:dBStartX+(distanceBtwBalls*CGFloat(i)), y:dBHeight)
ball.strokeColor = strokeColor
ball.name = "ball"
ball.fillColor = UIColor.clear
if i == 0 || i == totalBalls-1 {
ball.isHidden = true
}
addChild(ball)
}
mediaTimingFunctionEaseInEaseOutEmulate(node: dBCircle,dBStartX: dBStartX,dBStopX: dBStopX)
}
func mediaTimingFunctionEaseInEaseOutEmulate(node:SKShapeNode,dBStartX:CGFloat,dBStopX:CGFloat) {
let actionMoveLeft = SKAction.moveTo(x: dBStartX, duration:2.5)
actionMoveLeft.timingMode = SKActionTimingMode.easeInEaseOut
let actionMoveRight = SKAction.moveTo(x: dBStopX, duration:2.5)
actionMoveRight.timingMode = SKActionTimingMode.easeInEaseOut
node.run(SKAction.repeatForever(SKAction.sequence([actionMoveLeft,actionMoveRight])))
}
//MARK: - _metaball original function
func _metaball(circle2:SKShapeNode, circle1:SKShapeNode, v: CGFloat, handeLenRate: CGFloat, maxDistance: CGFloat,vanishingTime : TimeInterval = 0.015) {
let center1 = circle1.position
let center2 = circle2.position
let d = center1.distance(point: center2)
var radius1 = radiusDBCircle
var radius2 = radiusBall
if (radius1 == 0 || radius2 == 0) {
return
}
var u1: CGFloat = 0.0
var u2: CGFloat = 0.0
if (d > maxDistance || d <= abs(radius1 - radius2)) {
return
} else if (d < radius1 + radius2) {
u1 = acos((radius1 * radius1 + d * d - radius2 * radius2) / (2 * radius1 * d))
u2 = acos((radius2 * radius2 + d * d - radius1 * radius1) / (2 * radius2 * d))
} else {
u1 = 0.0
u2 = 0.0
}
let angle1 = center1.angleBetween(point: center2)
let angle2 = acos((radius1 - radius2) / d)
let angle1a = angle1 + u1 + (angle2 - u1) * v
let angle1b = angle1 - u1 - (angle2 - u1) * v
let angle2a = angle1 + CGFloat(M_PI) - u2 - (CGFloat(M_PI) - u2 - angle2) * v
let angle2b = angle1 - CGFloat(M_PI) + u2 + (CGFloat(M_PI) - u2 - angle2) * v
let p1a = center1.point(radians: angle1a, withLength: radius1)
let p1b = center1.point(radians: angle1b, withLength: radius1)
let p2a = center2.point(radians: angle2a, withLength: radius2)
let p2b = center2.point(radians: angle2b, withLength: radius2)
let totalRadius = radius1 + radius2
var d2 = min(v * handeLenRate, p1a.minus(point: p2a).length() / totalRadius)
d2 *= min(1, d * 2 / totalRadius)
radius1 *= d2
radius2 *= d2
let cp1a = p1a.point(radians: angle1a - CGFloat(M_PI_2), withLength: radius1)
let cp2a = p2a.point(radians: angle2a + CGFloat(M_PI_2), withLength: radius2)
let cp2b = p2b.point(radians: angle2b - CGFloat(M_PI_2), withLength: radius2)
let cp1b = p1b.point(radians: angle1b + CGFloat(M_PI_2), withLength: radius1)
let pathJoinedCircles = UIBezierPath()
pathJoinedCircles.move(to: p1a)
pathJoinedCircles.addCurve(to: p2a, controlPoint1: cp1a, controlPoint2: cp2a)
pathJoinedCircles.addLine(to: p2b)
pathJoinedCircles.addCurve(to: p1b, controlPoint1: cp2b, controlPoint2: cp1b)
pathJoinedCircles.addLine(to: p1a)
pathJoinedCircles.close()
let shapeNode = SKShapeNode(path: pathJoinedCircles.cgPath)
shapeNode.strokeColor = SKColor.orange
shapeNode.fillColor = UIColor.clear
addChild(shapeNode)
let wait = SKAction.wait(forDuration: vanishingTime)
self.run(wait,completion: {
shapeNode.removeFromParent()
})
}
override func update(_ currentTime: TimeInterval) {
var i = 0
self.enumerateChildNodes(withName: "ball") {
node, stop in
let ball = node as! SKShapeNode
let enlargeFrame = CGRect(x:ball.frame.origin.x-self.radiusBall*3,y:ball.frame.origin.y,width:ball.frame.width+(self.radiusBall*6),height:ball.frame.height)
if enlargeFrame.contains(self.dBCircle.frame) {
if (ball.action(forKey: "zoom") == nil) {
let zoomIn = SKAction.scale(to: 1.5, duration: 0.25)
zoomIn.timingMode = SKActionTimingMode.easeInEaseOut
let zoomOut = SKAction.scale(to: 1.0, duration: 0.25)
let wait = SKAction.wait(forDuration: 0.7)
let seq = SKAction.sequence([zoomIn,zoomOut,wait])
ball.run(seq,withKey: "zoom")
}
}
self._metaball(circle2: ball, circle1: self.dBCircle, v: 0.6, handeLenRate: 2.0, maxDistance: 5 * self.radiusBall)
i += 1
}
}
}
//MARK: - Extensions
extension CGPoint {
func distance(point: CGPoint) -> CGFloat {
let dx = point.x - self.x
let dy = point.y - self.y
return sqrt(dx * dx + dy * dy)
}
func angleBetween(point: CGPoint) -> CGFloat {
return atan2(point.y - self.y, point.x - self.x)
}
func point(radians: CGFloat, withLength length: CGFloat) -> CGPoint {
return CGPoint(x: self.x + length * cos(radians), y: self.y + length * sin(radians))
}
func minus(point: CGPoint) -> CGPoint {
return CGPoint(x: self.x - point.x, y: self.y - point.y)
}
func length() -> CGFloat {
return sqrt(self.x * self.x + self.y + self.y)
}
}
我正在尝试在 Metaballs 上重组此 Github Swift project，以便圆圈由 SKShapeNodes 表示，这些圆圈由 SKActions 而不是 CABasicAnimation 移动。
我对 viewController 中出现的各种 Metaball 参数（handleLenRate、Spacing 等）不感兴趣。我基本上希望能够使用 SKActions 为动画指定开始和结束位置。
我不确定如何实现这一点，尤其是如何用 SKShapeNode 的 SKActions 替换下面的 startAnimation 函数：
func startAnimation() {
let loadingLayer = self.layer as! DBMetaballLoadingLayer
loadingAnimation = CABasicAnimation(keyPath: "movingBallCenterX")
loadingAnimation!.duration = 2.5
loadingAnimation!.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
loadingAnimation!.fromValue = NSValue(CGPoint:fromPoint)
loadingAnimation!.toValue = NSValue(CGPoint: toPoint)
loadingAnimation!.repeatCount = Float.infinity
loadingAnimation!.autoreverses = true
loadingLayer.addAnimation(loadingAnimation!, forKey: "loading")
}
请在下方查看我能够执行的操作：
MBCircle class:
struct MBCircle {
var center: CGPoint = CGPointZero
var radius: CGFloat = 0.0
var frame: CGRect {
get {
return CGRect(x: center.x - radius, y: center.y - radius, width: 2 * radius, height: 2 * radius)
}
}
}
struct DefaultConfig {
static let radius: CGFloat = 15.0
static let mv: CGFloat = 0.6
static let maxDistance: CGFloat = 10 * DefaultConfig.radius
static let handleLenRate: CGFloat = 2.0
static let spacing: CGFloat = 160.0
}
GameScene class（代表DBMetaballLoadingLayer和DBMetaballLoadingView）：
class GameScene: SKScene {
private let MOVE_BALL_SCALE_RATE: CGFloat = 0.75
private let ITEM_COUNT = 2
private let SCALE_RATE: CGFloat = 1.0//0.3
private var circlePaths = [MBCircle]()
var radius: CGFloat = DefaultConfig.radius
var maxLength: CGFloat {
get {
return (radius * 4 + spacing) * CGFloat(ITEM_COUNT)
}
}
var maxDistance: CGFloat = DefaultConfig.maxDistance
var mv: CGFloat = DefaultConfig.mv
var spacing: CGFloat = DefaultConfig.spacing {
didSet {
_adjustSpacing(spacing)
}
}
var handleLenRate: CGFloat = DefaultConfig.handleLenRate
var movingBallCenterX : CGFloat = 0.0 {
didSet {
if (circlePaths.count > 0) {
circlePaths[0].center = CGPoint(x: movingBallCenterX, y: circlePaths[0].center.y)
}
}
}
func _generalInit() {
circlePaths = Array(0..<ITEM_COUNT).map { i in
var circlePath = MBCircle()
circlePath.center = CGPoint(x: (radius * 10 + spacing) * CGFloat(i), y: radius * (1.0 + SCALE_RATE))
circlePath.radius = i == 0 ? radius * MOVE_BALL_SCALE_RATE : radius
circlePath.sprite = SKShapeNode(circleOfRadius: circlePath.radius)
circlePath.sprite?.position = circlePath.center
circlePath.sprite?.fillColor = UIColor.blueColor()
addChild(circlePath.sprite!)
return circlePath
}
}
func _adjustSpacing(spacing: CGFloat) {
if (ITEM_COUNT > 1 && circlePaths.count > 1) {
for i in 1..<ITEM_COUNT {
var circlePath = circlePaths[i]
circlePath.center = CGPoint(x: (radius*2 + spacing) * CGFloat(i), y: radius * (1.0 + SCALE_RATE))
}
}
}
func _renderPath(path: UIBezierPath) {
var shapeNode = SKShapeNode()
shapeNode.path = path.CGPath
shapeNode.fillColor = UIColor.blueColor()
addChild(shapeNode)
}
func _metaball(j: Int, i: Int, v: CGFloat, handeLenRate: CGFloat, maxDistance: CGFloat) {
let circle1 = circlePaths[i]
let circle2 = circlePaths[j]
let center1 = circle1.center
let center2 = circle2.center
let d = center1.distance(center2)
var radius1 = circle1.radius
var radius2 = circle2.radius
if (d > maxDistance) {
_renderPath(UIBezierPath(ovalInRect: circle2.frame))
} else {
let scale2 = 1 + SCALE_RATE * (1 - d / maxDistance)
radius2 *= scale2
_renderPath(UIBezierPath(ovalInRect: CGRect(x: circle2.center.x - radius2, y: circle2.center.y - radius2, width: 2 * radius2, height: 2 * radius2)))
}
if (radius1 == 0 || radius2 == 0) {
return
}
var u1: CGFloat = 0.0
var u2: CGFloat = 0.0
if (d > maxDistance || d <= abs(radius1 - radius2)) {
return
} else if (d < radius1 + radius2) {
u1 = acos((radius1 * radius1 + d * d - radius2 * radius2) / (2 * radius1 * d))
u2 = acos((radius2 * radius2 + d * d - radius1 * radius1) / (2 * radius2 * d))
} else {
u1 = 0.0
u2 = 0.0
}
let angle1 = center1.angleBetween(center2)
let angle2 = acos((radius1 - radius2) / d)
let angle1a = angle1 + u1 + (angle2 - u1) * v
let angle1b = angle1 - u1 - (angle2 - u1) * v
let angle2a = angle1 + CGFloat(M_PI) - u2 - (CGFloat(M_PI) - u2 - angle2) * v
let angle2b = angle1 - CGFloat(M_PI) + u2 + (CGFloat(M_PI) - u2 - angle2) * v
let p1a = center1.point(radians: angle1a, withLength: radius1)
let p1b = center1.point(radians: angle1b, withLength: radius1)
let p2a = center2.point(radians: angle2a, withLength: radius2)
let p2b = center2.point(radians: angle2b, withLength: radius2)
let totalRadius = radius1 + radius2
var d2 = min(v * handeLenRate, p1a.minus(p2a).length() / totalRadius)
d2 *= min(1, d * 2 / totalRadius)
radius1 *= d2
radius2 *= d2
let cp1a = p1a.point(radians: angle1a - CGFloat(M_PI_2), withLength: radius1)
let cp2a = p2a.point(radians: angle2a + CGFloat(M_PI_2), withLength: radius2)
let cp2b = p2b.point(radians: angle2b - CGFloat(M_PI_2), withLength: radius2)
let cp1b = p1b.point(radians: angle1b + CGFloat(M_PI_2), withLength: radius1)
let pathJoinedCircles = UIBezierPath()
pathJoinedCircles.moveToPoint(p1a)
pathJoinedCircles.addCurveToPoint(p2a, controlPoint1: cp1a, controlPoint2: cp2a)
pathJoinedCircles.addLineToPoint(p2b)
pathJoinedCircles.addCurveToPoint(p1b, controlPoint1: cp2b, controlPoint2: cp1b)
pathJoinedCircles.addLineToPoint(p1a)
pathJoinedCircles.closePath()
_renderPath(pathJoinedCircles)
}
func startAnimation() {
}
override func didMoveToView(view: SKView) {
_generalInit()
}
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
}
}
我没有对CGPointExtensionclass进行任何更改。
更新
我仍在努力获得变形球效果，这是我目前根据 Alessandro Ornano 的建议取得的进展：
import SpriteKit
extension CGPoint {
func distance(point: CGPoint) -> CGFloat {
let dx = point.x - self.x
let dy = point.y - self.y
return sqrt(dx * dx + dy * dy)
}
func angleBetween(point: CGPoint) -> CGFloat {
return atan2(point.y - self.y, point.x - self.x)
}
func point(radians radians: CGFloat, withLength length: CGFloat) -> CGPoint {
return CGPoint(x: self.x + length * cos(radians), y: self.y + length * sin(radians))
}
func minus(point: CGPoint) -> CGPoint {
return CGPoint(x: self.x - point.x, y: self.y - point.y)
}
func length() -> CGFloat {
return sqrt(self.x * self.x + self.y + self.y)
}
}
class GameScene: SKScene {
var dBCircle : SKShapeNode!
let radiusDBCircle: CGFloat = 10
let radiusBall: CGFloat = 15
var balls = [SKShapeNode]()
var distanceBtwBalls : CGFloat = 15
private let SCALE_RATE: CGFloat = 0.3
override func didMoveToView(view: SKView) {
// Some parameters
let strokeColor = SKColor.orangeColor()
let dBHeight = CGRectGetMaxY(self.frame)-84 // 64 navigationController height + 20 reasonable distance
let dBStartX = CGRectGetMidX(self.frame)-160 // extreme left
let dBStopX = CGRectGetMidX(self.frame)+160 // extreme right
let dBWidth = dBStopX - dBStartX
let totalBalls = 7 // first and last will be hidden
let ballArea = dBWidth / CGFloat(totalBalls-1)
distanceBtwBalls = ((ballArea-(radiusBall*2))+radiusBall*2)
// Create dbCircle
dBCircle = SKShapeNode.init(circleOfRadius: radiusDBCircle)
dBCircle.position = CGPointMake(CGRectGetMidX(self.frame), dBHeight)
dBCircle.strokeColor = strokeColor
dBCircle.name = "dBCircle"
dBCircle.fillColor = UIColor.clearColor()
addChild(dBCircle)
// Make static balls
for i in 0..<totalBalls {
let ball = SKShapeNode.init(circleOfRadius: radiusBall)
ball.position = CGPointMake(dBStartX+(distanceBtwBalls*CGFloat(i)), dBHeight)
ball.strokeColor = strokeColor
ball.name = "ball"
ball.fillColor = UIColor.clearColor()
balls.append(ball)
if i == 0 || i == totalBalls-1 {
ball.hidden = true
}
addChild(ball)
}
mediaTimingFunctionEaseInEaseOutEmulate(dBCircle,dBStartX: dBStartX,dBStopX: dBStopX)
}
func mediaTimingFunctionEaseInEaseOutEmulate(node:SKShapeNode,dBStartX:CGFloat,dBStopX:CGFloat) {
let actionMoveLeft = SKAction.moveToX(dBStartX, duration:1.7)
actionMoveLeft.timingMode = SKActionTimingMode.EaseInEaseOut
let actionMoveRight = SKAction.moveToX(dBStopX, duration:1.7)
actionMoveRight.timingMode = SKActionTimingMode.EaseInEaseOut
node.runAction(SKAction.repeatActionForever(SKAction.sequence([actionMoveLeft,actionMoveRight])))
}
override func update(currentTime: NSTimeInterval) {
var i = 0
self.enumerateChildNodesWithName("ball") {
node, stop in
let ball = node as! SKShapeNode
if CGRectContainsRect(ball.frame, self.dBCircle.frame) {
if (ball.actionForKey("zoom") == nil) {
let zoomIn = SKAction.scaleTo(1.5, duration: 0.25)
let zoomOut = SKAction.scaleTo(1.0, duration: 0.25)
let seq = SKAction.sequence([zoomIn,zoomOut])
ball.runAction(seq,withKey: "zoom")
}
}
i += 1
}
movingBeziers()
}
func _renderPath(path: UIBezierPath) {
let shapeNode = SKShapeNode(path: path.CGPath)
shapeNode.fillColor = UIColor.blueColor()
addChild(shapeNode)
}
func movingBeziers() {
_renderPath(UIBezierPath(ovalInRect: dBCircle.frame))
for j in 1..<balls.count {
self.latestTestMetaball(j, circleShape: dBCircle, v: 0.6, handleLenRate: 2.0, maxDistance: self.distanceBtwBalls)
}
}
func latestTestMetaball (j: Int, circleShape: SKShapeNode, v: CGFloat, handleLenRate: CGFloat, maxDistance: CGFloat) {
let circle1 = circleShape
let circle2 = balls[j]
let center1 = circle1.position
let center2 = circle2.position
let d = center1.distance(center2)
var radius1 = circle1.frame.width
var radius2 = circle2.frame.width
var u1: CGFloat = 0.0
var u2: CGFloat = 0.0
if (d > maxDistance || d <= abs(radius1 - radius2)) {
return
} else if (d < radius1 + radius2) {
u1 = acos((radius1 * radius1 + d * d - radius2 * radius2) / (2 * radius1 * d))
u2 = acos((radius2 * radius2 + d * d - radius1 * radius1) / (2 * radius2 * d))
} else {
u1 = 0.0
u2 = 0.0
}
let angle1 = center1.angleBetween(center2)
let angle2 = acos((radius1 - radius2) / d)
let angle1a = angle1 + u1 + (angle2 - u1) * v
let angle1b = angle1 - u1 - (angle2 - u1) * v
let angle2a = angle1 + CGFloat(M_PI) - u2 - (CGFloat(M_PI) - u2 - angle2) * v
let angle2b = angle1 - CGFloat(M_PI) + u2 + (CGFloat(M_PI) - u2 - angle2) * v
let p1a = center1.point(radians: angle1a, withLength: radius1)
let p1b = center1.point(radians: angle1b, withLength: radius1)
let p2a = center2.point(radians: angle2a, withLength: radius2)
let p2b = center2.point(radians: angle2b, withLength: radius2)
let totalRadius = radius1 + radius2
var d2 = min(v * handleLenRate, p1a.minus(p2a).length() / totalRadius)
d2 *= min(1, d * 2 / totalRadius)
radius1 *= d2
radius2 *= d2
let cp1a = p1a.point(radians: angle1a - CGFloat(M_PI_2), withLength: radius1)
let cp2a = p2a.point(radians: angle2a + CGFloat(M_PI_2), withLength: radius2)
let cp2b = p2b.point(radians: angle2b - CGFloat(M_PI_2), withLength: radius2)
let cp1b = p1b.point(radians: angle1b + CGFloat(M_PI_2), withLength: radius1)
let pathJoinedCircles = UIBezierPath()
pathJoinedCircles.moveToPoint(p1a)
pathJoinedCircles.addCurveToPoint(p2a, controlPoint1: cp1a, controlPoint2: cp2a)
pathJoinedCircles.addLineToPoint(p2b)
pathJoinedCircles.addCurveToPoint(p1b, controlPoint1: cp2b, controlPoint2: cp1b)
pathJoinedCircles.addLineToPoint(p1a)
pathJoinedCircles.closePath()
let shapeNode = SKShapeNode(path: pathJoinedCircles.CGPath)
shapeNode.fillColor = UIColor.blueColor()
addChild(shapeNode)
}
}
假设您的问题是如何使用节点和 SKAction 复制相同的行为，我相信这应该可以做到。
var shapeNode : SKNode?
func startAnimation(){
if let node = self.shapeNode {
//assume that we have a node initialized at some point and added to the scene at some x1,y1 coordinates
/// we define parameters for the animation
let positionToReach = CGPoint(x: 100, y: 100) /// some random position
let currentPosition = node.position /// we need the current position to be able to reverse the "animation"
let animationDuration = 2.5 //loadingAnimation!.duration = 2.5
/// we define which actions will be run for the node
let actionForward = SKAction.moveTo(positionToReach, duration: animationDuration)
let actionBackwards = SKAction.moveTo(currentPosition, duration: animationDuration)
// we needed two actions to simulate loadingAnimation!.autoreverses = true
/// we wrap the actions in a sequence of actions
let actionSequence = SKAction.sequence([actionForward, actionBackwards]) /// animations to repeat
/// we want to repeat the animation forever
let actionToRepeat = SKAction.repeatActionForever(actionSequence) ///loadingAnimation!.repeatCount = Float.infinity
/// showtime
node.runAction(actionToRepeat)
}
}
如果我需要更新任何部分，请告诉我，因为我还没有测试过它。您仍然需要使用您的实际值和对象。
我在回复时提到了How would I repeat an action forever in Swift?。
您可以使用 moveToX 和 timingMode parameter.
新 Swift 3 翻译在下面这个答案的末尾。
举个例子我用Xcode Sprite-Kit "Hello, World!"官方项目demo:
class GameScene: SKScene {
override func didMoveToView(view: SKView) {
/* Setup your scene here */
let myLabel = SKLabelNode(fontNamed:"Chalkduster")
myLabel.text = "Hello, World!"
myLabel.fontSize = 15
myLabel.position = CGPoint(x:CGRectGetMidX(self.frame), y:CGRectGetMidY(self.frame))
self.addChild(myLabel)
mediaTimingFunctionEaseInEaseOutEmulate(myLabel)
}
func mediaTimingFunctionEaseInEaseOutEmulate(node:SKLabelNode) {
let actionMoveLeft = SKAction.moveToX(CGRectGetMidX(self.frame)-100, duration:1.5)
actionMoveLeft.timingMode = SKActionTimingMode.EaseInEaseOut
let actionMoveRight = SKAction.moveToX(CGRectGetMidX(self.frame)+100, duration:1.5)
actionMoveRight.timingMode = SKActionTimingMode.EaseInEaseOut
node.runAction(SKAction.repeatActionForever(SKAction.sequence([actionMoveLeft,actionMoveRight])))
}
}
输出:
更新（这部分开始模拟静态球和动态球左右移动但没有metaball动画）
class GameScene: SKScene {
var dBCircle : SKShapeNode!
let radiusDBCircle: CGFloat = 10
let radiusBall: CGFloat = 15
private let SCALE_RATE: CGFloat = 0.3
override func didMoveToView(view: SKView) {
// Some parameters
let strokeColor = SKColor.orangeColor()
let dBHeight = CGRectGetMaxY(self.frame)-84 // 64 navigationController height + 20 reasonable distance
let dBStartX = CGRectGetMidX(self.frame)-160 // extreme left
let dBStopX = CGRectGetMidX(self.frame)+160 // extreme right
let dBWidth = dBStopX - dBStartX
let totalBalls = 7 // first and last will be hidden
let ballArea = dBWidth / CGFloat(totalBalls-1)
let distanceBtwBalls = ((ballArea-(radiusBall*2))+radiusBall*2)
// Create dbCircle
dBCircle = SKShapeNode.init(circleOfRadius: radiusDBCircle)
dBCircle.position = CGPointMake(CGRectGetMidX(self.frame), dBHeight)
dBCircle.strokeColor = strokeColor
dBCircle.name = "dBCircle"
dBCircle.fillColor = UIColor.clearColor()
addChild(dBCircle)
// Make static balls
for i in 0..<totalBalls {
let ball = SKShapeNode.init(circleOfRadius: radiusBall)
ball.position = CGPointMake(dBStartX+(distanceBtwBalls*CGFloat(i)), dBHeight)
ball.strokeColor = strokeColor
ball.name = "ball"
ball.fillColor = UIColor.clearColor()
if i == 0 || i == totalBalls-1 {
ball.hidden = true
}
addChild(ball)
}
mediaTimingFunctionEaseInEaseOutEmulate(dBCircle,dBStartX: dBStartX,dBStopX: dBStopX)
}
func mediaTimingFunctionEaseInEaseOutEmulate(node:SKShapeNode,dBStartX:CGFloat,dBStopX:CGFloat) {
let actionMoveLeft = SKAction.moveToX(dBStartX, duration:1.7)
actionMoveLeft.timingMode = SKActionTimingMode.EaseInEaseOut
let actionMoveRight = SKAction.moveToX(dBStopX, duration:1.7)
actionMoveRight.timingMode = SKActionTimingMode.EaseInEaseOut
node.runAction(SKAction.repeatActionForever(SKAction.sequence([actionMoveLeft,actionMoveRight])))
}
override func update(currentTime: NSTimeInterval) {
var i = 0
self.enumerateChildNodesWithName("ball") {
node, stop in
let ball = node as! SKShapeNode
if CGRectContainsRect(ball.frame, self.dBCircle.frame) {
if (ball.actionForKey("zoom") == nil) {
let zoomIn = SKAction.scaleTo(1.5, duration: 0.25)
let zoomOut = SKAction.scaleTo(1.0, duration: 0.25)
let seq = SKAction.sequence([zoomIn,zoomOut])
ball.runAction(seq,withKey: "zoom")
}
}
i += 1
}
}
}
新的元球动画更新:
终于实现了这个结果，我的目标是让它和原来的非常相似:
是否可以对时间进行一些变化（例如 zoomIn 或 zoomOut 时间值或 actionMoveLeft、actionMoveRight 时间值），这是代码：
import SpriteKit
class GameScene: SKScene {
var dBCircle : SKShapeNode!
let radiusDBCircle: CGFloat = 10
let radiusBall: CGFloat = 15
private let SCALE_RATE: CGFloat = 0.3
override func didMoveToView(view: SKView) {
// Some parameters
let strokeColor = SKColor.orangeColor()
let dBHeight = CGRectGetMaxY(self.frame)-84 // 64 navigationController height + 20 reasonable distance
let dBStartX = CGRectGetMidX(self.frame)-160 // extreme left
let dBStopX = CGRectGetMidX(self.frame)+160 // extreme right
let dBWidth = dBStopX - dBStartX
let totalBalls = 7 // first and last will be hidden
let ballArea = dBWidth / CGFloat(totalBalls-1)
let distanceBtwBalls = ((ballArea-(radiusBall*2))+radiusBall*2)
// Create dbCircle
dBCircle = SKShapeNode.init(circleOfRadius: radiusDBCircle)
dBCircle.position = CGPointMake(CGRectGetMidX(self.frame), dBHeight)
dBCircle.strokeColor = strokeColor
dBCircle.name = "dBCircle"
dBCircle.fillColor = UIColor.clearColor()
addChild(dBCircle)
// Make static balls
for i in 0..<totalBalls {
let ball = SKShapeNode.init(circleOfRadius: radiusBall)
ball.position = CGPointMake(dBStartX+(distanceBtwBalls*CGFloat(i)), dBHeight)
ball.strokeColor = strokeColor
ball.name = "ball"
ball.fillColor = UIColor.clearColor()
if i == 0 || i == totalBalls-1 {
ball.hidden = true
}
addChild(ball)
}
mediaTimingFunctionEaseInEaseOutEmulate(dBCircle,dBStartX: dBStartX,dBStopX: dBStopX)
}
func mediaTimingFunctionEaseInEaseOutEmulate(node:SKShapeNode,dBStartX:CGFloat,dBStopX:CGFloat) {
let actionMoveLeft = SKAction.moveToX(dBStartX, duration:2.5)
actionMoveLeft.timingMode = SKActionTimingMode.EaseInEaseOut
let actionMoveRight = SKAction.moveToX(dBStopX, duration:2.5)
actionMoveRight.timingMode = SKActionTimingMode.EaseInEaseOut
node.runAction(SKAction.repeatActionForever(SKAction.sequence([actionMoveLeft,actionMoveRight])))
}
//MARK: - _metaball original function
func _metaball(circle2:SKShapeNode, circle1:SKShapeNode, v: CGFloat, handeLenRate: CGFloat, maxDistance: CGFloat,vanishingTime : NSTimeInterval = 0.015) {
let center1 = circle1.position
let center2 = circle2.position
let d = center1.distance(center2)
var radius1 = radiusDBCircle
var radius2 = radiusBall
if (radius1 == 0 || radius2 == 0) {
return
}
var u1: CGFloat = 0.0
var u2: CGFloat = 0.0
if (d > maxDistance || d <= abs(radius1 - radius2)) {
return
} else if (d < radius1 + radius2) {
u1 = acos((radius1 * radius1 + d * d - radius2 * radius2) / (2 * radius1 * d))
u2 = acos((radius2 * radius2 + d * d - radius1 * radius1) / (2 * radius2 * d))
} else {
u1 = 0.0
u2 = 0.0
}
let angle1 = center1.angleBetween(center2)
let angle2 = acos((radius1 - radius2) / d)
let angle1a = angle1 + u1 + (angle2 - u1) * v
let angle1b = angle1 - u1 - (angle2 - u1) * v
let angle2a = angle1 + CGFloat(M_PI) - u2 - (CGFloat(M_PI) - u2 - angle2) * v
let angle2b = angle1 - CGFloat(M_PI) + u2 + (CGFloat(M_PI) - u2 - angle2) * v
let p1a = center1.point(radians: angle1a, withLength: radius1)
let p1b = center1.point(radians: angle1b, withLength: radius1)
let p2a = center2.point(radians: angle2a, withLength: radius2)
let p2b = center2.point(radians: angle2b, withLength: radius2)
let totalRadius = radius1 + radius2
var d2 = min(v * handeLenRate, p1a.minus(p2a).length() / totalRadius)
d2 *= min(1, d * 2 / totalRadius)
radius1 *= d2
radius2 *= d2
let cp1a = p1a.point(radians: angle1a - CGFloat(M_PI_2), withLength: radius1)
let cp2a = p2a.point(radians: angle2a + CGFloat(M_PI_2), withLength: radius2)
let cp2b = p2b.point(radians: angle2b - CGFloat(M_PI_2), withLength: radius2)
let cp1b = p1b.point(radians: angle1b + CGFloat(M_PI_2), withLength: radius1)
let pathJoinedCircles = UIBezierPath()
pathJoinedCircles.moveToPoint(p1a)
pathJoinedCircles.addCurveToPoint(p2a, controlPoint1: cp1a, controlPoint2: cp2a)
pathJoinedCircles.addLineToPoint(p2b)
pathJoinedCircles.addCurveToPoint(p1b, controlPoint1: cp2b, controlPoint2: cp1b)
pathJoinedCircles.addLineToPoint(p1a)
pathJoinedCircles.closePath()
let shapeNode = SKShapeNode(path: pathJoinedCircles.CGPath)
shapeNode.strokeColor = SKColor.orangeColor()
shapeNode.fillColor = UIColor.clearColor()
addChild(shapeNode)
let wait = SKAction.waitForDuration(vanishingTime)
self.runAction(wait,completion: {
shapeNode.removeFromParent()
})
}
override func update(currentTime: NSTimeInterval) {
var i = 0
self.enumerateChildNodesWithName("ball") {
node, stop in
let ball = node as! SKShapeNode
let enlargeFrame = CGRectMake(ball.frame.origin.x-self.radiusBall*3,ball.frame.origin.y,ball.frame.width+(self.radiusBall*6),ball.frame.height)
if CGRectContainsRect(enlargeFrame, self.dBCircle.frame) {
if (ball.actionForKey("zoom") == nil) {
let zoomIn = SKAction.scaleTo(1.5, duration: 0.25)
zoomIn.timingMode = SKActionTimingMode.EaseInEaseOut
let zoomOut = SKAction.scaleTo(1.0, duration: 0.25)
let wait = SKAction.waitForDuration(0.8)
let seq = SKAction.sequence([zoomIn,zoomOut,wait])
ball.runAction(seq,withKey: "zoom")
}
}
self._metaball(ball, circle1: self.dBCircle, v: 0.6, handeLenRate: 2.0, maxDistance: 4 * self.radiusBall)
i += 1
}
}
}
//MARK: - Extensions
extension CGPoint {
func distance(point: CGPoint) -> CGFloat {
let dx = point.x - self.x
let dy = point.y - self.y
return sqrt(dx * dx + dy * dy)
}
func angleBetween(point: CGPoint) -> CGFloat {
return atan2(point.y - self.y, point.x - self.x)
}
func point(radians radians: CGFloat, withLength length: CGFloat) -> CGPoint {
return CGPoint(x: self.x + length * cos(radians), y: self.y + length * sin(radians))
}
func minus(point: CGPoint) -> CGPoint {
return CGPoint(x: self.x - point.x, y: self.y - point.y)
}
func length() -> CGFloat {
return sqrt(self.x * self.x + self.y + self.y)
}
}
Swift 3:
（我用 maxDistance: 5 * self.radiusBall 对 maxDistance: 4 * self.radiusBall 做了一点改动，使其与原始版本更相似，但您可以根据需要进行更改）
import SpriteKit
class GameScene: SKScene {
var dBCircle : SKShapeNode!
let radiusDBCircle: CGFloat = 10
let radiusBall: CGFloat = 15
private let SCALE_RATE: CGFloat = 0.3
override func didMove(to view: SKView) {
let label = self.childNode(withName: "//helloLabel") as? SKLabelNode
label?.removeFromParent()
self.anchorPoint = CGPoint.zero
// Some parameters
let strokeColor = SKColor.orange
let dBHeight = self.frame.midY
let dBStartX = self.frame.midX-260 // extreme left
let dBStopX = self.frame.midX+260 // extreme right
let dBWidth = dBStopX - dBStartX
let totalBalls = 7 // first and last will be hidden
let ballArea = dBWidth / CGFloat(totalBalls-1)
let distanceBtwBalls = ((ballArea-(radiusBall*2))+radiusBall*2)
// Create dbCircle
dBCircle = SKShapeNode.init(circleOfRadius: radiusDBCircle)
dBCircle.position = CGPoint(x:self.frame.midX, y:dBHeight)
dBCircle.strokeColor = strokeColor
dBCircle.name = "dBCircle"
dBCircle.fillColor = UIColor.clear
addChild(dBCircle)
// Make static balls
for i in 0..<totalBalls {
let ball = SKShapeNode.init(circleOfRadius: radiusBall)
ball.position = CGPoint(x:dBStartX+(distanceBtwBalls*CGFloat(i)), y:dBHeight)
ball.strokeColor = strokeColor
ball.name = "ball"
ball.fillColor = UIColor.clear
if i == 0 || i == totalBalls-1 {
ball.isHidden = true
}
addChild(ball)
}
mediaTimingFunctionEaseInEaseOutEmulate(node: dBCircle,dBStartX: dBStartX,dBStopX: dBStopX)
}
func mediaTimingFunctionEaseInEaseOutEmulate(node:SKShapeNode,dBStartX:CGFloat,dBStopX:CGFloat) {
let actionMoveLeft = SKAction.moveTo(x: dBStartX, duration:2.5)
actionMoveLeft.timingMode = SKActionTimingMode.easeInEaseOut
let actionMoveRight = SKAction.moveTo(x: dBStopX, duration:2.5)
actionMoveRight.timingMode = SKActionTimingMode.easeInEaseOut
node.run(SKAction.repeatForever(SKAction.sequence([actionMoveLeft,actionMoveRight])))
}
//MARK: - _metaball original function
func _metaball(circle2:SKShapeNode, circle1:SKShapeNode, v: CGFloat, handeLenRate: CGFloat, maxDistance: CGFloat,vanishingTime : TimeInterval = 0.015) {
let center1 = circle1.position
let center2 = circle2.position
let d = center1.distance(point: center2)
var radius1 = radiusDBCircle
var radius2 = radiusBall
if (radius1 == 0 || radius2 == 0) {
return
}
var u1: CGFloat = 0.0
var u2: CGFloat = 0.0
if (d > maxDistance || d <= abs(radius1 - radius2)) {
return
} else if (d < radius1 + radius2) {
u1 = acos((radius1 * radius1 + d * d - radius2 * radius2) / (2 * radius1 * d))
u2 = acos((radius2 * radius2 + d * d - radius1 * radius1) / (2 * radius2 * d))
} else {
u1 = 0.0
u2 = 0.0
}
let angle1 = center1.angleBetween(point: center2)
let angle2 = acos((radius1 - radius2) / d)
let angle1a = angle1 + u1 + (angle2 - u1) * v
let angle1b = angle1 - u1 - (angle2 - u1) * v
let angle2a = angle1 + CGFloat(M_PI) - u2 - (CGFloat(M_PI) - u2 - angle2) * v
let angle2b = angle1 - CGFloat(M_PI) + u2 + (CGFloat(M_PI) - u2 - angle2) * v
let p1a = center1.point(radians: angle1a, withLength: radius1)
let p1b = center1.point(radians: angle1b, withLength: radius1)
let p2a = center2.point(radians: angle2a, withLength: radius2)
let p2b = center2.point(radians: angle2b, withLength: radius2)
let totalRadius = radius1 + radius2
var d2 = min(v * handeLenRate, p1a.minus(point: p2a).length() / totalRadius)
d2 *= min(1, d * 2 / totalRadius)
radius1 *= d2
radius2 *= d2
let cp1a = p1a.point(radians: angle1a - CGFloat(M_PI_2), withLength: radius1)
let cp2a = p2a.point(radians: angle2a + CGFloat(M_PI_2), withLength: radius2)
let cp2b = p2b.point(radians: angle2b - CGFloat(M_PI_2), withLength: radius2)
let cp1b = p1b.point(radians: angle1b + CGFloat(M_PI_2), withLength: radius1)
let pathJoinedCircles = UIBezierPath()
pathJoinedCircles.move(to: p1a)
pathJoinedCircles.addCurve(to: p2a, controlPoint1: cp1a, controlPoint2: cp2a)
pathJoinedCircles.addLine(to: p2b)
pathJoinedCircles.addCurve(to: p1b, controlPoint1: cp2b, controlPoint2: cp1b)
pathJoinedCircles.addLine(to: p1a)
pathJoinedCircles.close()
let shapeNode = SKShapeNode(path: pathJoinedCircles.cgPath)
shapeNode.strokeColor = SKColor.orange
shapeNode.fillColor = UIColor.clear
addChild(shapeNode)
let wait = SKAction.wait(forDuration: vanishingTime)
self.run(wait,completion: {
shapeNode.removeFromParent()
})
}
override func update(_ currentTime: TimeInterval) {
var i = 0
self.enumerateChildNodes(withName: "ball") {
node, stop in
let ball = node as! SKShapeNode
let enlargeFrame = CGRect(x:ball.frame.origin.x-self.radiusBall*3,y:ball.frame.origin.y,width:ball.frame.width+(self.radiusBall*6),height:ball.frame.height)
if enlargeFrame.contains(self.dBCircle.frame) {
if (ball.action(forKey: "zoom") == nil) {
let zoomIn = SKAction.scale(to: 1.5, duration: 0.25)
zoomIn.timingMode = SKActionTimingMode.easeInEaseOut
let zoomOut = SKAction.scale(to: 1.0, duration: 0.25)
let wait = SKAction.wait(forDuration: 0.7)
let seq = SKAction.sequence([zoomIn,zoomOut,wait])
ball.run(seq,withKey: "zoom")
}
}
self._metaball(circle2: ball, circle1: self.dBCircle, v: 0.6, handeLenRate: 2.0, maxDistance: 5 * self.radiusBall)
i += 1
}
}
}
//MARK: - Extensions
extension CGPoint {
func distance(point: CGPoint) -> CGFloat {
let dx = point.x - self.x
let dy = point.y - self.y
return sqrt(dx * dx + dy * dy)
}
func angleBetween(point: CGPoint) -> CGFloat {
return atan2(point.y - self.y, point.x - self.x)
}
func point(radians: CGFloat, withLength length: CGFloat) -> CGPoint {
return CGPoint(x: self.x + length * cos(radians), y: self.y + length * sin(radians))
}
func minus(point: CGPoint) -> CGPoint {
return CGPoint(x: self.x - point.x, y: self.y - point.y)
}
func length() -> CGFloat {
return sqrt(self.x * self.x + self.y + self.y)
}
}