How Do I Blur a Scene in SpriteKit?

Question

How would I add a gaussian blur to all nodes (there\'s no fixed number of nodes) in an SKScene in SpriteKit? A label will be added on top of the scene later, this will be m

Answer 1

To add to this by using @Bendegúz's answer and code from http://www.bytearray.org/?p=5360

I was able to get this to work in my current game project that's being done in IOS 8 Swift. Done a bit differently by returning an SKSpriteNode instead of a UIImage. Also note that my unwrapped currentScene.view! call is to a weak GameScene reference but should work with self.view.frame based on where you are calling these methods. My pause screen is called in a separate HUD class hence why this is the case.

I would imagine this could be done more elegantly, maybe more like @jemmons's answer. Just wanted to possibly help out anyone else trying to do this in SpriteKit projects written in all or some Swift code.

func getBluredScreenshot() -> SKSpriteNode{

    create the graphics context
    UIGraphicsBeginImageContextWithOptions(CGSize(width: currentScene.view!.frame.size.width, height: currentScene.view!.frame.size.height), true, 1)

    currentScene.view!.drawViewHierarchyInRect(currentScene.view!.frame, afterScreenUpdates: true)

    // retrieve graphics context
    let context = UIGraphicsGetCurrentContext()

    // query image from it
    let image = UIGraphicsGetImageFromCurrentImageContext()

    // create Core Image context
    let ciContext = CIContext(options: nil)
    // create a CIImage, think of a CIImage as image data for processing, nothing is displayed or can be displayed at this point
    let coreImage = CIImage(image: image)
    // pick the filter we want
    let filter = CIFilter(name: "CIGaussianBlur")
    // pass our image as input
    filter.setValue(coreImage, forKey: kCIInputImageKey)

    //edit the amount of blur
    filter.setValue(3, forKey: kCIInputRadiusKey)

    //retrieve the processed image
    let filteredImageData = filter.valueForKey(kCIOutputImageKey) as CIImage
    // return a Quartz image from the Core Image context
    let filteredImageRef = ciContext.createCGImage(filteredImageData, fromRect: filteredImageData.extent())
    // final UIImage
    let filteredImage = UIImage(CGImage: filteredImageRef)

    // create a texture, pass the UIImage
    let texture = SKTexture(image: filteredImage!)
    // wrap it inside a sprite node
    let sprite = SKSpriteNode(texture:texture)

    // make image the position in the center
    sprite.position = CGPointMake(CGRectGetMidX(currentScene.frame), CGRectGetMidY(currentScene.frame))

    var scale:CGFloat = UIScreen.mainScreen().scale

    sprite.size.width  *= scale

    sprite.size.height *= scale

    return sprite


}


func loadPauseBGScreen(){

    let duration = 1.0

    let pauseBG:SKSpriteNode = self.getBluredScreenshot()

    //pauseBG.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame))
    pauseBG.alpha = 0
    pauseBG.zPosition = self.zPosition + 1
    pauseBG.runAction(SKAction.fadeAlphaTo(1, duration: duration))

    self.addChild(pauseBG)

}