Why the flatten stage process the data in the local space?

Nobody has claimed this yet.

Hi there

I am re-reading the vello shader code recently, I found the flatten stage uses the local space to process the curve to the line segments **with the scale factor to deal with the stroke width**.

But why it is in local space?

First I think the local space wastes lots of compute. If I can transform it in the screen space, maybe I can filter out the data at first.

Second, what if my scale is not isotropic？ Like in x axis scale 2, but in y axis scale only 0.5?

This is pretty common when I have the stroke width fixed in screen space, not in local space. Also I have to deal with the transformation which is very likely to be anisotropy.

Really hope to get some reply.

Thanks a lot!

Start by reading the Vello shader code for the flatten stage and tracing how local-space curves, line segments, scale factors, and stroke width are handled. Investigate the consequences of moving processing to screen space, including early filtering and anisotropic transforms. Done would require a documented design decision or an agreed implementation plan for these cases.

Written by the indexing model from the issue text.