[cairo] Mozilla on Cairo

Robert O'Callahan rocallahan at novell.com
Wed May 11 14:24:14 PDT 2005

On Wed, 2005-05-11 at 12:02 -0400, mental at rydia.net wrote:
> Quoting Robert O'Callahan <rocallahan at novell.com>:
> > But FSAA is a combination of "turn off pixel-coverage
> > antialiasing" and "render to a larger buffer and scale down with
> > pixel averaging".  So the first step to supporting FSAA is to be
> > able to turn off the coverage antialiasing. Then, when resources
> > permit, we can add supersampling.
> Well, that's only one of many approaches to doing FSAA.
> One alternative would be storing all the trapezoids to be rendered
> in a BSP tree and then rendering them in a single pass at the end. 
> That would permit you to do the partial coverage calculations "for
> real", rather than faking it through accumulating alpha
> compositing.
> Depending on the complexity of the scene, it may be more or less
> efficient than FSAA via supersampling.

For software-only renderers the efficiency might be comparable, but the
full-scene trapezoid approach is less amenable to hardware acceleration,
correct? (I mean using the hardware we actually have, as opposed to
hardware that could theoretically be built.)


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