[webkit-dev] Accelerated 2D Tesselation Implementation

[Nico Weber]

On Fri, Aug 27, 2010 at 10:18 AM, Chris Marrin <cmarrin at apple.com> wrote:
>
> Hi Ken,
> It would help me, and I think many others, if we could have a discussion of
> how exactly your tessellation logic works and what it is intended to do. For
> instance, is the algorithm you're using based on Loop-Blinn? I'm a bit
> familiar with that algorithm and some of the problems it has with rendering
> this type of geometry. For instance, there are typically anti-aliasing
> artifacts at the points where the interior triangles touch the edges. These
> are described in section 5.1 of the paper and the authors added additional
> (and not well described) logic to solve the problem.
> If you could describe your algorithm a bit and show some expected results
> with typical cases, that would be really helpful.
> For those not familiar with Loop-Blinn, here is a link to their original
> paper, presented at Siggraph 2005:
> Resolution Independent Curve Rendering using Programmable Graphics ...
> It's a great algorithm for rendering resolution independent 2D objects using
> the GPU. It has potential to render both 2D shapes (as used in Canvas and
> SVG) and text glyphs. It's advantage is that once you generate the triangles
> for the shape, you can render the shape at any resolution. It's disadvantage
> is that the triangle generation is quite expensive, so mutating shapes can
> potentially be slower than a simpler resolution dependent tessellation.

I think there's a variant of the algorithm that uses the stencil
buffer polygon rendering method (
http://zrusin.blogspot.com/2006/07/hardware-accelerated-polygon-rendering.html
) instead of triangulation. The paper I think I read on that only
covered quadratic splines, but maybe somehow has extended that method
to cubic splines by now?

Nico

> -----
> ~Chris
> cmarrin at apple.com
>
>
>
>
> _______________________________________________
> webkit-dev mailing list
> webkit-dev at lists.webkit.org
> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
>
>