class SKFieldNode : SKNode {
    var region: SKRegion?
    var strength: Float
    var falloff: Float
    var minimumRadius: Float
    var isEnabled: Bool
    var isExclusive: Bool
    var categoryBitMask: UInt32
    var direction: vector_float3
    var smoothness: Float
    var animationSpeed: Float
    var texture: SKTexture?
    class func dragField() -> SKFieldNode
    class func vortexField() -> SKFieldNode
    class func radialGravityField() -> SKFieldNode
    class func linearGravityField(withVector direction: vector_float3) -> SKFieldNode
    class func velocityField(withVector direction: vector_float3) -> SKFieldNode
    class func velocityField(with velocityTexture: SKTexture) -> SKFieldNode
    class func noiseField(withSmoothness smoothness: CGFloat, animationSpeed speed: CGFloat) -> SKFieldNode
    class func turbulenceField(withSmoothness smoothness: CGFloat, animationSpeed speed: CGFloat) -> SKFieldNode
    class func springField() -> SKFieldNode
    class func electricField() -> SKFieldNode
    class func magneticField() -> SKFieldNode
    class func customField(evaluationBlock block: SpriteKit.SKFieldForceEvaluator) -> SKFieldNode
}

class SKFieldNode : SKNode {
    var region: SKRegion?
    var strength: Float
    var falloff: Float
    var minimumRadius: Float
    var isEnabled: Bool
    var isExclusive: Bool
    var categoryBitMask: UInt32
    var direction: vector_float3
    var smoothness: Float
    var animationSpeed: Float
    var texture: SKTexture?
    class func dragField() -> SKFieldNode
    class func vortexField() -> SKFieldNode
    class func radialGravityField() -> SKFieldNode
    class func linearGravityField(withVector direction: vector_float3) -> SKFieldNode
    class func velocityField(withVector direction: vector_float3) -> SKFieldNode
    class func velocityField(with velocityTexture: SKTexture) -> SKFieldNode
    class func noiseField(withSmoothness smoothness: CGFloat, animationSpeed speed: CGFloat) -> SKFieldNode
    class func turbulenceField(withSmoothness smoothness: CGFloat, animationSpeed speed: CGFloat) -> SKFieldNode
    class func springField() -> SKFieldNode
    class func electricField() -> SKFieldNode
    class func magneticField() -> SKFieldNode
    class func customField(evaluationBlock block: @escaping SpriteKit.SKFieldForceEvaluator) -> SKFieldNode
}

class func customField(evaluationBlock block: SpriteKit.SKFieldForceEvaluator) -> SKFieldNode

class func customField(evaluationBlock block: @escaping SpriteKit.SKFieldForceEvaluator) -> SKFieldNode