contrast_renderer VS vger-rs

This is true, but there is a lot more to the story. For one, WebGPU does not (yet) support mesh shaders, though it may later as an extension. For two, consider a glyph such as "o" that has two contours. Real triangulation generates a mesh that only generates triangles between the outer and inner contours, and mesh shaders aren't good at that. There are techniques (cover and stencil) that draw twice, incrementing and decrementing a winding number stored in the stencil buffer (see contrast renderer[1] for a clean modern implementation), but it does require nontrivial tracking on the CPU side, and can result in lots of draw calls to switch between the cover and stencil stages unless sophisticated batching is done.

Compute shaders avoid all these problems and work on WebGPU 1.0 today.

[1]: https://github.com/Lichtso/contrast_renderer

Thanks!

You can also checkout the "feature/ui" branch in GIT [1] to get the UI framework prototype.

[1]: https://github.com/Lichtso/contrast_renderer/tree/feature/ui

I've done a library for vector graphics on the GPU which works pretty well for my uses:

https://github.com/audulus/vger

and a rust version:

https://github.com/audulus/vger-rs

(which powers my rust GUI library: https://github.com/audulus/rui)

Here's the approach for rendering path fills. From the readme:

> The bezier path fill case is somewhat original. To avoid having to solve quadratic equations (which has numerical issues), the fragment function uses a sort-of reverse Loop-Blinn. To determine if a point is inside or outside, vger tests against the lines formed between the endpoints of each bezier curve, flipping inside/outside for each intersection with a +x ray from the point. Then vger tests the point against the area between the bezier segment and the line, flipping inside/outside again if inside. This avoids the pre-computation of Loop-Blinn, and the AA issues of Kokojima.

It works pretty well, and doesn't require as much preprocessing as the code in the article. Also doesn't require any GPU compute (though I do use GPU compute for some things). I think ultimately the approach in the article (essentially Piet-metal, aka tessellating and binning into tiles) will deliver better performance, and support more primitives, but at greater implementation complexity. I've tried the Piet-metal approach myself and it's tricky! I like the simpler Shadertoy/SDF inspired approach :)