SpriteKit 的相机抖动效果

Question

有没有人知道一些开箱即用的库，可以为SKNode 提供相机抖动等效果？

如果没有，有没有一种简单的方法可以使用动作来实现相机抖动？

谢谢

Answer 1

我发现了一种使用 SKAction 的优雅方法，它可以让你的节点动摇。例如，水平摇动：

-(void)shake:(NSInteger)times {
    CGPoint initialPoint = self.position;
    NSInteger amplitudeX = 32;
    NSInteger amplitudeY = 2;
    NSMutableArray * randomActions = [NSMutableArray array];
    for (int i=0; i<times; i++) {
        NSInteger randX = self.position.x+arc4random() % amplitudeX - amplitudeX/2;
        NSInteger randY = self.position.y+arc4random() % amplitudeY - amplitudeY/2;
        SKAction *action = [SKAction moveTo:CGPointMake(randX, randY) duration:0.01];
        [randomActions addObject:action];
    }

    SKAction *rep = [SKAction sequence:randomActions];

    [self runAction:rep completion:^{
        self.position = initialPoint;
    }];
}

Answer 2

已接受答案中的抖动方法有一个警告 - 它只能应用于其 x,y 坐标未被其他正在运行的 SKAction 修改的节点。这是因为我们在摇动完成后将节点的位置重置为其初始位置。

如果您想要一个可以与其他 SKAction 一起工作的摇动动作，这些 SKAction 会按顺序/平行修改摇动节点的位置（x 或 y 坐标），您需要添加正在应用的随机摇动的反向动作。

一个 Swift 扩展供参考：

extension SKAction {
class func shake(duration:CGFloat, amplitudeX:Int = 3, amplitudeY:Int = 3) -> SKAction {
    let numberOfShakes = duration / 0.015 / 2.0
    var actionsArray:[SKAction] = []
    for index in 1...Int(numberOfShakes) {
        let dx = CGFloat(arc4random_uniform(UInt32(amplitudeX))) - CGFloat(amplitudeX / 2)
        let dy = CGFloat(arc4random_uniform(UInt32(amplitudeY))) - CGFloat(amplitudeY / 2)
        let forward = SKAction.moveByX(dx, y:dy, duration: 0.015)
        let reverse = forward.reversedAction()
        actionsArray.append(forward)
        actionsArray.append(reverse)
    }
    return SKAction.sequence(actionsArray)
}
}

注意，这个修改不需要将节点作为参数传入

Answer 3

如果你已经在使用 Swift，你可以使用下面的代码...

let shake = SKAction.shake(node.position, duration: 0.3)
node.runAction(shake)

或者为了更强烈的震动，您也可以配置振幅

let shake = SKAction.shake(node.position, duration: 0.3, amplitudeX: 12, amplitudeY: 3)
node.runAction(shake)

这是扩展名....

extension SKAction {
    class func shake(initialPosition:CGPoint, duration:Float, amplitudeX:Int = 12, amplitudeY:Int = 3) -> SKAction {
        let startingX = initialPosition.x
        let startingY = initialPosition.y
        let numberOfShakes = duration / 0.015
        var actionsArray:[SKAction] = []
        for index in 1...Int(numberOfShakes) {
            let newXPos = startingX + CGFloat(arc4random_uniform(UInt32(amplitudeX))) - CGFloat(amplitudeX / 2)
            let newYPos = startingY + CGFloat(arc4random_uniform(UInt32(amplitudeY))) - CGFloat(amplitudeY / 2)
            actionsArray.append(SKAction.moveTo(CGPointMake(newXPos, newYPos), duration: 0.015))
        }
        actionsArray.append(SKAction.moveTo(initialPosition, duration: 0.015))
        return SKAction.sequence(actionsArray)
    }
}

感谢 Stephen Haney 我刚刚将它移到扩展中的实现

Answer 4

如果你想动摇整个场景，这里是 Rob 用 Swift 编写的答案的一个版本：

    func sceneShake(shakeCount: Int, intensity: CGVector, shakeDuration: Double) {
        let sceneView = self.scene!.view! as UIView
        let shakeAnimation = CABasicAnimation(keyPath: "position")

        shakeAnimation.duration = shakeDuration / Double(shakeCount)
        shakeAnimation.repeatCount = Float(shakeCount)
        shakeAnimation.autoreverses = true
        shakeAnimation.fromValue = NSValue(cgPoint: CGPoint(x: sceneView.center.x - intensity.dx, y: sceneView.center.y - intensity.dy))
        shakeAnimation.toValue = NSValue(cgPoint: CGPoint(x: sceneView.center.x + intensity.dx, y: sceneView.center.y + intensity.dy))

        sceneView.layer.add(shakeAnimation, forKey: "position")
      }

我将此函数包含在 SKScene 子类中。这是一个示例调用：

    sceneShake(shakeCount: 3, intensity: CGVector(dx: shakeIntensity, dy: shakeIntensity), shakeDuration: shakeDuration)

Answer 5

这是我使用的方法。希望能帮助到你。根据需要修改它。

-(void)shakeScreenFor:(int)numberOfShakes withIntensity:(CGVector)intensity andDuration:(CGFloat)duration{
    UIView *sceneView = self.scene.view;
    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"position"];
    [animation setDuration:(duration/numberOfShakes)];
    [animation setRepeatCount:numberOfShakes];
    [animation setAutoreverses:YES];
    [animation setFromValue:[NSValue valueWithCGPoint: CGPointMake([sceneView center].x - intensity.dx, [sceneView center].y - intensity.dy)]];
    [animation setToValue:[NSValue valueWithCGPoint: CGPointMake([sceneView center].x + intensity.dx, [sceneView center].y + intensity.dy)]];
    [[sceneView layer] addAnimation:animation forKey:@"position"];
}

Answer 6

@Benzi 的 Swift 4 版本回答：

func shake(duration: Double, amplitudeX: CGFloat = 3, amplitudeY: CGFloat = 3) -> SKAction {
    let numberOfShakes = duration / 0.015 / 2.0
    var actionsArray:[SKAction] = []
    for _ in 1...Int(numberOfShakes) {
        let dx = CGFloat(arc4random_uniform(UInt32(amplitudeX))) - CGFloat(amplitudeX / 2)
        let dy = CGFloat(arc4random_uniform(UInt32(amplitudeY))) - CGFloat(amplitudeY / 2)
        let forward = SKAction.moveBy(x: dx, y:dy, duration: 0.015)
        let reverse = forward.reversed()
        actionsArray.append(forward)
        actionsArray.append(reverse)
    }
    return SKAction.sequence(actionsArray)
}

Answer 7

-(void)screen_shake
 {
   if (shake)
   {
    current_number_of_shakes++;

    float randx = (float)[self randomValueBetween:1 and:90]/50.0f;

    if ([self randomValueBetween:0 and:1] == 0)
        randx = -randx;

    float randy = (float)[self randomValueBetween:1 and:90]/50.0f;

    if ([self randomValueBetween:0 and:1] == 0)
        randy = -randy;


    camera.position = CGPointMake(camera.position.x + randx, camera.position.y + randy);

    if (current_number_of_shakes >= total_amount_of_shakes)
    {

        current_number_of_shakes = 0;
        move_back_from_shake = YES;
        [camera runAction:[SKAction sequence:@[[SKAction moveTo:start_point_before_shake duration:.7], [SKAction performSelector:@selector(shake_done) onTarget:self]]]];

    }




   }

}

经过一些工作和参考人们的做法，Cocoa2D 就是我想出的。在您的更新方法中，您将需要调用此方法。您可以填写一些常量，但我希望这对所有需要它的人有所帮助。此外，shake_done 所做的所有方法都是将 Bool 抖动更新为 false。