I thought we decided that "blend" only made sense if the images were essentially being combined via "over". So it seems to me that the alpha ought to just use the regular "over" formula.
As for z (or any other channels not identified as alpha), really none of the compositing operations make sense for z, so just treat it as any other color channel and let the user live with their misguided attempt to composite or blend depth values. I'll let others chime in if I'm totally off-base on that. On Jul 16, 2012, at 3:49 PM, Stefan Stavrev wrote: > How should ImageBufAlgo::blend deal with images that have > an alpha channel? > > Blending makes sense only for color channels, so I think > we should allow images with alpha channels, but we should > skip the alpha channel in the blending step. > > What about Z channel, do the same thing? > > Another option is to apply blending to all channels, > no matter alpha or Z. Then, it would be the user's > responsibility to provide us only with color channels. -- Larry Gritz [email protected] _______________________________________________ Oiio-dev mailing list [email protected] http://lists.openimageio.org/listinfo.cgi/oiio-dev-openimageio.org
