Don't confuse subpixel accuracy with any form of anti-aliasing. It just means vertices are not snapped to the centers of pixels before rasterizing. It's explained in very great detail in Chris Hecker's articles.
Here's a good illustration I found: - Windows: http://www.antigrain.com/demo/idea.zip - Linux: http://www.antigrain.com/demo/idea.tar.gz Set Rotate on, Draft on (no anti-aliasing), and then toggle Roundoff to see the effect of subpixel accuracy. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Timothy Miller Sent: dinsdag 1 februari 2005 22:13 To: Daniel Phillips Cc: [EMAIL PROTECTED]; [email protected] Subject: Re: [Open-graphics] Accurate rasterizaton Daniel Phillips wrote: > On Tuesday 01 February 2005 15:46, you wrote: > >>>>>Y should be fixed point too, IMHO. >>>> >>>>Y is integer. The software is responsible for adjusting all other >>>>parameters to be correct. See the model source for how that is >>>>done. >>> >>>I meant, before being converted to pixel coordinates. >> >>Right. That's done in the host, so I assume it'll always be in >>float. To the hardware Y is ALWAYS an integer. > > > My kneejerk reaction is, we don't want to throw away the extra precision > before it gets to the card, it's needed for coverage calculations and > the like, if we ever get that far. I suggest sending hardware Y in the > same format as hardware X, whatever that is. > > Besides that, I am a big fan of subpixel screen coordinates, even for 2D > graphics, for example, font rendering. That's the thing... we've discussed coverage, full-screen antialiasing, subpixel coordinates and the like, and the experts here have almost unanimously said that they're unnecessary. (Some can be emulated anyhow.) If we decide to support it now or in the future, it'll matter, but for now, it seems to be something we can just drop. If you have a compelling argument contrary to that, feel free to discuss it with the others. Note that the design, as it is, has probably seriously blown our transistor budget, so don't get your hopes up, even about some things that are ALREADY in there. BTW, font-rendering from xft is pre-antialiased. It's just a grayscale bitmap that we use as the alpha channel while texturing. _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com) _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
