在 Swift 中为 SKSprite 添加渐变

如何解决在 Swift 中为 SKSprite 添加渐变

尝试在 Swift 中为 Sprite 添加纹理。

找到了这个解决方案，看起来不错。

https://maximbilan.medium.com/sprite-kit-gradient-1ffb7ec35c6a

写于 2016 年，所以从那时起不得不修复一些语法更改，但卡在最后一行。

    public enum GradientDirection {
      case Up
      case Left
      case UpLeft
      case UpRight
    }

    public extension SKTexture {
    
    convenience init(size: CGSize,color1: CIColor,color2: CIColor,direction: GradientDirection = .Up) {
        
        let context = CIContext(options: nil)
        let filter = CIFilter(name: "CILinearGradient")
        var startVector: CIVector
        var endVector: CIVector
        
        filter!.setDefaults()
        
        switch direction {
            case .Up:
                startVector = CIVector(x: size.width * 0.5,y: 0)
                endVector = CIVector(x: size.width * 0.5,y: size.height)
            case .Left:
                startVector = CIVector(x: size.width,y: size.height * 0.5)
                endVector = CIVector(x: 0,y: size.height * 0.5)
            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)
        }
        
        filter!.setValue(startVector,forKey: "inputPoint0")
        filter!.setValue(endVector,forKey: "inputPoint1")
        filter!.setValue(color1,forKey: "inputColor0")
        filter!.setValue(color2,forKey: "inputColor1")
        
        let image = context.createCGImage(filter!.outputimage!,from: CGRect(x: 0,y: 0,width: size.width,height: size.height))!
        self(cgImage: image) <- Syntax here wrong??
    }
    }

self(cgImage: image) 行的语法错误。

你像这样使用它（语法需要从 2016 年开始更新）。

    let topColor = CIColor(rgba: "#71B280")
    let bottomColor = CIColor(rgba: "#134E5E")

    let texture = SKTexture(size: CGSizeMake(200,200),color1: topColor,color2:     bottomColor,direction: GradientDirection.Up)
    texture.filteringMode = .Nearest
    let sprite = SKSpriteNode(texture: texture)
    sprite.position = CGPointMake(CGRectGetMidX(frame),CGRectGetMidY(frame))
    sprite.size = self.frame.size
    addChild(sprite)