我正在使用 SpriteKit 开发一款游戏。我正在用 SKShapeNode 绘制一个形状。现在我想为其颜色变化设置动画，但 SKActions 不适用于 SKShapeNode。有没有办法做到这一点，或者我必须使用不同的方法？

谢谢。

编辑:

感谢LearnCocos2D我能够想出这个快速(但并不完美)的解决方案。

int groundChangeInterval = 5;
SKColor *originalColor = [SKColor colorWithRed:0.92 green:0.87 blue:0.38 alpha:1.0];
SKColor *finalColor = [SKColor colorWithRed:0.29 green:0.89 blue:0.31 alpha:1.0];

CGFloat red1 = 0.0, green1 = 0.0, blue1 = 0.0, alpha1 = 0.0;
[originalColor getRed:&red1 green:&green1 blue:&blue1 alpha:&alpha1];

CGFloat red2 = 0.0, green2 = 0.0, blue2 = 0.0, alpha2 = 0.0;
[finalColor getRed:&red2 green:&green2 blue:&blue2 alpha:&alpha2];

SKAction *changeGroundColor = [SKAction customActionWithDuration:groundChangeInterval actionBlock:^(SKNode *node, CGFloat elapsedTime) {
    CGFloat step = elapsedTime/groundChangeInterval;

    CGFloat red3 = 0.0, green3 = 0.0, blue3 = 0.0;
    red3 = red1-(red1-red2)*step;
    green3 = green1-(green1-green2)*step;
    blue3 = blue1-(blue1-blue2)*step;

    [(SKShapeNode*)node setFillColor:[SKColor colorWithRed:red3 green:green3 blue:blue3 alpha:1.0]];
    [(SKShapeNode*)node setStrokeColor:[SKColor colorWithRed:red3 green:green3 blue:blue3 alpha:1.0]];
}];

我只需要淡化两种特定的颜色，所以这不是一个通用的解决方案，但现在已经足够了。

谢谢

最佳答案

针对 Swift 4.2 进行了更新

这是您需要放入的通用代码和扩展文件或类似的东西。

func lerp(a : CGFloat, b : CGFloat, fraction : CGFloat) -> CGFloat
{
    return (b-a) * fraction + a
}

struct ColorComponents {
    var red = CGFloat(0)
    var green = CGFloat(0)
    var blue = CGFloat(0)
    var alpha = CGFloat(0)
}

extension UIColor {
    func toComponents() -> ColorComponents {
        var components = ColorComponents()
        getRed(&components.red, green: &components.green, blue: &components.blue, alpha: &components.alpha)
        return components
    }
}

extension SKAction {
    static func colorTransitionAction(fromColor : UIColor, toColor : UIColor, duration : Double = 0.4) -> SKAction
    {
        return SKAction.customAction(withDuration: duration, actionBlock: { (node : SKNode!, elapsedTime : CGFloat) -> Void in
            let fraction = CGFloat(elapsedTime / CGFloat(duration))
            let startColorComponents = fromColor.toComponents()
            let endColorComponents = toColor.toComponents()
            let transColor = UIColor(red: lerp(a: startColorComponents.red, b: endColorComponents.red, fraction: fraction),
                                     green: lerp(a: startColorComponents.green, b: endColorComponents.green, fraction: fraction),
                                     blue: lerp(a: startColorComponents.blue, b: endColorComponents.blue, fraction: fraction),
                                     alpha: lerp(a: startColorComponents.alpha, b: endColorComponents.alpha, fraction: fraction))
            (node as? SKSpriteNode)?.color = transColor
        }
        )
    }
}

用法:

redSKSpriteNodeThatBecomesBlue.run(SKAction.colorTransitionAction(fromColor: .red, toColor: .blue, duration: 5))

请注意，对于 SKShapeNode 或其他目的，您需要重写此行以满足您的需要:

(node as?SKSpriteNode)?.color = transColor

这个解决方案的灵感最初来自 Paddy Collins 的回答。

关于ios - SKShapeNode - 动画颜色变化，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20872556/