CODEWITHSUNDEEP
iossprite-kitmotion-detectionsknode
haawa
haawa

Reputation: 3104

Motion effect for SKNode

I'm getting int SpriteKit. And would like to know how to create motion effect on SKNode object.

For UIView I use following method :

+(void)registerEffectForView:(UIView *)aView
                   depth:(CGFloat)depth
{
UIInterpolatingMotionEffect *effectX;
UIInterpolatingMotionEffect *effectY;
effectX = [[UIInterpolatingMotionEffect alloc] initWithKeyPath:@"center.x"
                                                          type:UIInterpolatingMotionEffectTypeTiltAlongHorizontalAxis];
effectY = [[UIInterpolatingMotionEffect alloc] initWithKeyPath:@"center.y"
                                                          type:UIInterpolatingMotionEffectTypeTiltAlongVerticalAxis];


effectX.maximumRelativeValue = @(depth);
effectX.minimumRelativeValue = @(-depth);
effectY.maximumRelativeValue = @(depth);
effectY.minimumRelativeValue = @(-depth);

[aView addMotionEffect:effectX];
[aView addMotionEffect:effectY];
}

I haven't found anything similar for SKNode. So my question is is it possible? And if not then how can I implement it.

Upvotes: 0

Views: 1326

Answers (2)

user5865651
user5865651

Reputation: 1558

UIInterpolatingMotionEffect works in deep level and you can't use an arbitrary keyPath like "cloudX". Even after adding motionEffects, the actual value of centre property won't change. So the answer is, you can't add a motion effect other than UIView. Using arbitrary property other than particular property such as 'center' or 'frame' is not possible either.

Upvotes: 0

rickster
rickster

Reputation: 126177

UIInterpolatingMotionEffect just maps the device tilt to properties of the view it's applied to -- it's all about what keyPaths you set it up with, and what the setters for those key paths do.

The example you posted maps horizontal tilt to the x coordinate of the view's center property. When the device is tilted horizontally, UIKit automatically calls setCenter: on the view (or sets view.center =, if you prefer your syntax that way), passing a point whose X coordinate is offset proportionally to the amount of horizontal tilt.

You can just as well define custom properties on a custom UIView subclass. Since you're working with Sprite Kit, you can subclass SKView to add properties.

For example... say you have a cloud sprite in your scene that you want to move as the user tilts the device. Name it as a property in your SKScene subclass:

@interface MyScene : SKScene
@property SKSpriteNode *cloud;
@end

And add properties and accessors in your SKView subclass that move it:

@implementation MyView // (excerpt)

- (CGFloat)cloudX {
    return ((MyScene *)self.scene).cloud.position.x;
}
- (void)setCloudX:(CGFloat)x {
    SKSpriteNode *cloud = ((MyScene *)self.scene).cloud;
    cloud.position = CGPointMake(x, cloud.position.y);
}

@end

Now, you can create a UIInterpolatingMotionEffect whose keyPath is cloudX, and it should* automagically move the sprite in your scene.

(* totally untested code)

Upvotes: 0

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