CAGradientLayer的3D旋转动画

Question

如何在用户点击3D CAGradientLayer时从左向右旋转，并在第二次点击后向后旋转（从右向左）？而且我还需要在动画的中间将渐变更改为不同的颜色（基本上是当视图旋转90度并从用户的眼睛中“隐藏”时）

由于某种原因，我的实现只在一个方向（从左到右）旋转视图。我曾尝试过使用负数PI，但结果有点怪异。 我到目前为止所拥有的

func open() {

    var flipTransform: CATransform3D
    flipTransform = CATransform3DIdentity
    flipTransform.m34 = 1.0 / -1000
    flipTransform = CATransform3DRotate(flipTransform, .pi, 0.0, 1.0, 0.0)

    UIView.animate(withDuration: 2.0, animations: {
        self.tile.layer.transform = flipTransform
        DispatchQueue.main.asyncAfter(deadline: .now() + self.duration / 2, execute: {
            self.addGradientLayer(from: .red, to: .yellow)
        })
    })
}

func close() {

    UIView.animate(withDuration: 2.0, animations: {
        self.tile.layer.transform = CATransform3DIdentity
        DispatchQueue.main.asyncAfter(deadline: .now() + self.duration / 2, execute: {
            self.addGradientLayer(from: .black, to: .lightGray)
        })
    })

}

func addGradientLayer(from: UIColor, to: UIColor) {
    tile.layer.sublayers?.filter { $0 is CAGradientLayer }.forEach { $0.removeFromSuperlayer() }
    let gradientLayer = CAGradientLayer()
    gradientLayer.frame = tile.bounds
    gradientLayer.colors = [from.cgColor, to.cgColor]
    gradientLayer.locations = [0.0, 1.0]
    gradientLayer.endPoint = CGPoint(x: 1.0, y: 1.0)
    gradientLayer.startPoint = CGPoint(x: 0.0, y: 0.0)
    tile.layer.insertSublayer(gradientLayer, at: 0)
}