ios – SpriteKit – SKCameraNode视差效果？

我一直在试验SKCameraNode,但我找不到任何关于用它创建视差效果的东西.

假设我添加上面的代码,并在baseNode下面添加一个后台节点.然后我动画我的相机.

let behindNode = SKNode()
addChild(behindNode)

let blueSquare = SKSpriteNode(color: SKColor.blueColor(), size: CGSize(width: 80, height: 80))
blueSquare.position = CGPoint(x: size.width/2+40, y: size.height/2+40)
behindNode.addChild(blueSquare)

let baseNode = SKNode()
addChild(baseNode)

let redSquare = SKSpriteNode(color: SKColor.redColor(), size: CGSize(width: 80, height: 80))
redSquare.position = CGPoint(x: size.width/2, y: size.height/2)
baseNode.addChild(redSquare)


let cameraNode = SKCameraNode()
camera = cameraNode
addChild(camera!)
camera!.position = redSquare.position

cameraNode.runAction(SKAction.sequence([
    SKAction.waitForDuration(1),
    SKAction.moveBy(CGVector(dx: 100, dy: 100), duration: 3),
    SKAction.moveBy(CGVector(dx: -100, dy: 100), duration: 1),
    SKAction.moveBy(CGVector(dx: 100, dy: -100), duration: 1)
]))

当相机移动时,我需要蓝色方块相对于红色方块以较慢的速度移动..我希望cameranode有相对位置字典或其他东西,但它不会…

我创建了一个不处理秒或帧的解决方案.

您可以创建SKCameraNode的子类,并使用Swift的didSet()方法,该方法在更改类变量后调用.在我们的例子中,我们想要监听摄像机节点位置变量的变化.

class CameraNodeParallax:SKCameraNode{

override var position : CGPoint {
    didSet {  
       // Move our backgrounds
    }
}

我们还希望创建一个包含所有视差背景节点的阵列,以及一个包含相对于摄像机移动速度的相应移动速度的阵列.

var backgroundNodes:[SKNode] = []
var backgroundNodesSpeedFactor:[CGVector] = [] // in relation to camera nodes speed

func addParallaxBackgroundNode(background:SKNode, vector:CGVector) {
    backgroundNodes.append(background)
    backgroundNodesSpeedFactor.append(vector)
}

填充我们的新变量的init()也可能很有用

init(position:CGPoint) {
  super.init()
  self.position = position
}

现在我们可以填充didSet()监听器：

// Move our backgrounds
var i = 0
for node in backgroundNodes {

    let positionChangeX = position.x-oldValue.x
    let positionChangeY = position.y-oldValue.y
    let changeX = positionChangeX*backgroundNodesSpeedFactor[i].dx
    let changeY = positionChangeY*backgroundNodesSpeedFactor[i].dy
    node.position = CGPointMake(node.position.x+changeX,node.position.y+changeY)

    i += 1
}

最终代码如下所示：

class CameraNodeParallax:SKCameraNode{

    var backgroundNodes:[SKNode] = []
    var backgroundNodesSpeedFactor:[CGVector] = [] // in relation to camera nodes speed

    init(position:CGPoint) {
        super.init()
        self.position = position
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override var position : CGPoint {
        didSet {

            // Move your parallax backgrounds
                var i = 0
                for node in backgroundNodes {

                    let positionChangeX = position.x-oldValue.x
                    let positionChangeY = position.y-oldValue.y
                    let changeX = positionChangeX*backgroundNodesSpeedFactor[i].dx
                    let changeY = positionChangeY*backgroundNodesSpeedFactor[i].dy
                    node.position = CGPointMake(node.position.x+changeX,node.position.y+changeY)

                    i += 1
                }
        }
    }

    func addParallaxBackgroundNode(background:SKNode, vector:CGVector) {
        backgroundNodes.append(background)
        backgroundNodesSpeedFactor.append(vector)
    }
}

我在https://github.com/gitmalong/lovelySpriteKitHelpers/blob/master/ParallaxBackgroundMover.swift创建了一个不从SKCameraNode继承的替代实现