blurring shape boundaries

    Mar 18 2009 | 4:29 pm
    Hi all,
    This is probably a ridiculously simple question, but I haven't done much (any?) work in creating images in gl (I'm usually creating images outside jitter and playing back in jitter). I'm creating a simple circle (right now using and controlling scaling, position, and color. What I am trying to add is a blurring/feathering of the border, e.g. much like a radial blur in photoshop. And...I would love to be able to control the amount of blurring...otherwise I'd just create the image in photoshop.
    Any pointers? Just not sure what object(s) to use to produce the desired effect.

    • Mar 18 2009 | 5:03 pm
      not as simple as you'd think. the best/only way to post-process opengl (such as blurring) is to capture to texture and run your texture through a slab with a blur shader.
      this recent post does just that. my response at the end shows how to correctly do alpha-blending of multiple textures.
      see if that gets it going for you.