The "Parabola Segment - exact" and "Polygon - exact" examples in particular. Probably requires some combination of the two for your use case. Basically turn your lines into 2D SDF objects that define the outside of your object.
I think most of those objects actually could be chained together, like the actual quadratic bezier example has a real interior and exterior when you look at it more closely: https://www.shadertoy.com/view/MlKcDD
So yeah, the intersection of a bunch of line segment SDFs like that could do it. A bit more completed than that but that's the basic principle. Not sure about the performance... There is probably a more efficient way to do it, but I don't have the math skills to figure it out.
One approach would be to construct one solid SDF object out of a bunch of 2D SDF object segements: https://iquilezles.org/articles/distfunctions2d/
The "Parabola Segment - exact" and "Polygon - exact" examples in particular. Probably requires some combination of the two for your use case. Basically turn your lines into 2D SDF objects that define the outside of your object.
I think most of those objects actually could be chained together, like the actual quadratic bezier example has a real interior and exterior when you look at it more closely: https://www.shadertoy.com/view/MlKcDD
So yeah, the intersection of a bunch of line segment SDFs like that could do it. A bit more completed than that but that's the basic principle. Not sure about the performance... There is probably a more efficient way to do it, but I don't have the math skills to figure it out.