public class SphereRefraction: BasicOperation {
    public var radius: Float = 0.25 { didSet { uniformSettings["radius"] = radius } }
    public var refractiveIndex: Float = 0.71 { didSet { uniformSettings["refractiveIndex"] = refractiveIndex } }
    public var center: Position = Position.center { didSet { uniformSettings["center"] = center } }

    public init() {
        super.init(fragmentShader: SphereRefractionFragmentShader, numberOfInputs: 1)

        ({ radius = 0.25 })()
        ({ refractiveIndex = 0.71 })()
        ({ center = Position.center })()

        backgroundColor = Color(red: 0.0, green: 0.0, blue: 0.0, alpha: 0.0)
    }
}
