ios - 这个 SKShapeNode 渐变着色代码有什么问题？

Question

我正在尝试创建渐变色 SKShapeNode。

我从 theGoogle 中找到了下面的代码 但它仅在 color1 为黑色时有效，例如定义如下:

CIColor.init(red: 0, green: 0, blue: 0, alpha: 1.0) 

第二种颜色可以是任何颜色。

enum GradientDirection {
    case up
    case left
    case upLeft
    case upRight
}
extension SKTexture {
    convenience init(size:CGSize,color1:CIColor,color2:CIColor,direction:GradientDirection = .up) {
        let coreImageContext = CIContext(options: nil)
        let gradientFilter = CIFilter(name: "CILinearGradient")
        gradientFilter!.setDefaults()
        var startVector:CIVector
        var endVector:CIVector
        switch direction {
        case .up:
            startVector = CIVector(x: size.width/2, y: 0)
            endVector = CIVector(x: size.width/2, y: size.height)
        case .left:
            startVector = CIVector(x: size.width, y: size.height/2)
            endVector = CIVector(x: 0, y: size.height/2)
        case .upLeft:
            startVector = CIVector(x: size.width, y: 0)
            endVector = CIVector(x: 0, y: size.height)
        case .upRight:
            startVector = CIVector(x: 0, y: 0)
            endVector = CIVector(x: size.width, y: size.height)

        }
        gradientFilter!.setValue(startVector, forKey: "inputPoint0")
        gradientFilter!.setValue(endVector, forKey: "inputPoint1")
        gradientFilter!.setValue(color1, forKey: "inputColor0")
        gradientFilter!.setValue(color2, forKey: "inputColor1")
        let cgimg = coreImageContext.createCGImage(gradientFilter!.outputImage!, fromRect: CGRect(x: 0, y: 0, width: size.width, height: size.height))
        self.init(CGImage:cgimg)
    }
}

我希望颜色不是黑色。我不知道这段代码有什么问题。我定义 SKShapeNode 如下:

let textureSize = CGSize(width: shapeNode.frame.width, height: shapeNode.frame.height)
let bottomColor = CIColor.init(red: 0, green: 0, blue: 0, alpha: 1.0)
let topColor = CIColor.init(red: 225, green: 255, blue: 255, alpha: 1.0)
let shapeTexture = SKTexture(size:textureSize, color1:bottomColor, color2:topColor, direction:GradientDirection.up)
shapeNode.fillTexture = shapeTexture
self.addChild(shapeNode)

感谢所有帮助!

Answer 1

CIColor 的 RGB 值应该在 [0, 1] 中。 255 不是有效值。