I recently added a rendering pass in my engine to compute volumetric shapes via raymarching.

[mirth@mastodon.sdf.org]

@froyok The math would take some thought but it might be possible to sample the vertical and horizontally squished versions at render time, do the threshold, and skip the larger intermediate texture entirely Then the shadows would have fewer artifacts and the overall memory bandwidth used should be smaller.

(this feels like the kind of idea that one of the elder graphics people will chime in and be able to point out some prior art and improvements from 25 years ago)

[froyok@mastodon.gamedev.place]

@mirth Given the critical part here is the edges, the demonstration you propose doesn't help on this issue.
Then one solution could be compute bits at half-res where there isn't edges (so edges are at full res), but this sounds a bit like the MSAA or Variable rate solution that were proposed in other replies, they are unfortunately difficult to implement in my engine.