On Aug 27, 2010, at 10:32 AM, Nico Weber wrote: > On Fri, Aug 27, 2010 at 10:18 AM, Chris Marrin <cmar...@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?
It looks like that technique deals with polygons, so as long as you convert the shape to a piecewise linear curve it seems like it can handle any curve form, right? ----- ~Chris cmar...@apple.com _______________________________________________ webkit-dev mailing list webkit-dev@lists.webkit.org http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev