swift - SpriteKit Action ，例如“Skew”或“Distort”

是否可以在SpriteKit中为SKSpriteNode创建SKAction，该SKAction使用“编辑->变换->扭曲”选项生成与“Photoshop”相同的效果？
例子：

最佳答案

可以使用1x1扭曲网格创建扭曲。这在iOS10.0+中受支持。
此扩展以度为单位接收倾斜角度，并围绕给定精灵的锚点扭曲。
银行代码4.2

extension SKWarpGeometryGrid {

    public static var skewPosGridZero:[float2] {
        get {
            return [float2(0.0, 0.0), float2(1.0, 0.0),
                    float2(0.0, 1.0), float2(1.0, 1.0)]
        }
    }

    public static func skewXPosGrid(_ skewX: CGFloat, node:SKSpriteNode? = nil) -> [float2] {

        let anchorY:Float = Float(node?.anchorPoint.y ?? 0.5)
        var skewPosGrid = skewPosGridZero
        let offsetX = Float(tan(skewX.degToRad()) * (node == nil ? 1.0 : (node!.size.height/node!.size.width)) )
        skewPosGrid[2][0] += offsetX * (1.0 - anchorY)
        skewPosGrid[3][0] += offsetX * (1.0 - anchorY)
        skewPosGrid[0][0] -= offsetX * anchorY
        skewPosGrid[1][0] -= offsetX * anchorY

        return skewPosGrid

    }

    public static func skewYPosGrid(_ skewY: CGFloat, node:SKSpriteNode? = nil) -> [float2] {

        let anchorX:Float = Float(node?.anchorPoint.x ?? 0.5)
        var skewPosGrid = skewPosGridZero
        let offsetY = Float(tan(skewY.degToRad()) * (node == nil ? 1.0 : (node!.size.width/node!.size.height)) )
        skewPosGrid[1][1] += offsetY * (1.0 - anchorX)
        skewPosGrid[3][1] += offsetY * (1.0 - anchorX)
        skewPosGrid[0][1] -= offsetY * anchorX
        skewPosGrid[2][1] -= offsetY * anchorX

        return skewPosGrid

    }

    public static func skewX(_ angle: CGFloat, node:SKSpriteNode? = nil) -> SKWarpGeometryGrid {

        return SKWarpGeometryGrid(columns: 1, rows: 1, sourcePositions: skewPosGridZero, destinationPositions: skewXPosGrid(angle, node:node))

    }
    public static func skewY(_ angle: CGFloat, node:SKSpriteNode? = nil) -> SKWarpGeometryGrid {

        return SKWarpGeometryGrid(columns: 1, rows: 1, sourcePositions: skewPosGridZero, destinationPositions: skewYPosGrid(angle, node:node))

    }

    public static func skewZero() -> SKWarpGeometryGrid {
        return SKWarpGeometryGrid(columns: 1, rows: 1)
    }

}

动画示例：

    let spriteNode = SKSpriteNode(imageNamed: "tex")
    spriteNode.anchorPoint = CGPoint(x:0.25, y:1.0)
    let skewA = SKWarpGeometryGrid.skewX(-45.0, node: spriteNode)
    let skewB = SKWarpGeometryGrid.skewX(45.0, node: spriteNode)
    spriteNode.warpGeometry = skewB
    if let skewActionA = SKAction.warp(to: skewA, duration: 3.0),
        let skewActionB = SKAction.warp(to: skewB, duration: 3.0){
        // Individual easing
        skewActionA.timingMode = .easeInEaseOut
        skewActionB.timingMode = .easeInEaseOut
        spriteNode.run(SKAction.repeatForever(SKAction.sequence([skewActionA,skewActionB])))
    }

关于swift - SpriteKit Action ，例如“Skew”或“Distort”，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/43443168/