问雪碧试剂盒中的混合颜色

EN

class GameScene:SKScene{

    override func didMoveToView(view: SKView) {


        let effect = SKEffectNode()

        //Creating shapenodes
        let shape1 = SKShapeNode(circleOfRadius: 50)
        shape1.fillColor = SKColor.redColor()
        shape1.strokeColor = SKColor.clearColor()
        shape1.zPosition = 1
        shape1.blendMode = SKBlendMode.Add

        let shape2 = SKShapeNode(circleOfRadius: 50)
        shape2.fillColor = SKColor.greenColor()
        shape2.strokeColor = SKColor.clearColor()
        shape2.zPosition = 2
        shape2.blendMode = SKBlendMode.Add

        let shape3 = SKShapeNode(circleOfRadius: 50)
        shape3.fillColor = SKColor.blueColor()
        shape3.strokeColor = SKColor.clearColor()
        shape3.zPosition = 3
        shape3.blendMode = SKBlendMode.Add


        //Positioning
        shape1.position = CGPoint(x: CGRectGetMidX(frame), y: CGRectGetMidY(frame))

        shape2.position = CGPoint(x: shape1.position.x - 25, y: shape1.position.y - 50)

        shape3.position = CGPoint(x: shape1.position.x + 25, y: shape1.position.y - 50)

        effect.addChild(shape1)
        effect.addChild(shape2)
        effect.addChild(shape3)

        self.addChild(effect)

    }
}