Can someone provide an example of how to progressively blur a SKSpriteNode's image using Apple's Sprite Kit? For instance, let's say the user touches a button on the screen which will then trigger the background to slowly (i.e. progressively) blur until it reaches a specific threshold. Ideally, I would like to reverse the process too (e.g. allow the user to unblur the image by touching the same button).
There are two possible paths to take on this, both use SKEffectNodes
SKEffectNodes allow you to apply CI Filters to a node.
There is a CI Filter for Gaussian Blur. So Create a SKEffectNode, and assign it a blur filter, then add the button as a child.
How do you animate it?
Use SKAction to create a custom action, and change the parameters of filter, however, this can be slow and doesn't always give the 'progressive' blur effect you might expect, so what I do is this:
I create a filter and SKEffectNode like described above, then I render the result to a Texture, using SKView.textureForNode. I then add the resulting texture to an array, after that I loop this, continuinng to apply the blur effect on top of the previous image created, until I have a set number of frames. Then use the textures created to make an animation with SKAction.animateWithTextures. In my experience, this comes out very nicely.
来源：https://stackoverflow.com/questions/19729409/how-to-progressively-blur-a-skspritenodes-image-using-sprite-kit