Re: Gaussian blur kernels
Jon Watte <[email protected]>
| Newsgroups | gmane.games.devel.algorithms |
|---|---|
| Message-ID | <[email protected]> |
Fabian Giesen wrote: > However, all of this is a non-issue in graphics. Pixel shaders give you > cheap pointwise evaluations at no cost. If you want only every second > pixel, then render a quad half the size in each direction. > > But that cheap sample is using a pretty crappy box area filter for its sampling, so it is not aliasing free. > In short, the optimal "polyphase" implementation of a 5x5 Gaussian > followed by a 2:1 downsample in both directions is just to render to the > smaller rendertarget directly with the 5x5 Gaussian Pixel shader and the > correct texture coordinates. > > But originally the problem wasn't just downsampling -- it was using some combination of downsampling, filtering and upsampling to approximate the result of a bigger Gaussian blur, but making it faster. Sincerely, jw -- Revenge is the most pointless and damaging of human desires. ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/Challenge _______________________________________________ GDAlgorithms-list mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list