CRT VGA double scanlines in ScummVM

[Taiyaki]

Has anyone managed to get satisfying double scanlines in Scummvm either via a specific shader or by modifying an existing one?

Some time ago "DOSBox Staging" set by default to use shaders that emulate CRT VGA monitors by running double scanlines through each pixel. Basically all the games that ran in 320x2xx resolutions look shockingly convincing to what I think most of us remember throughout the 90's (attaching a sample photo below of what this looks like).

For many reasons I much prefer ScummVM for the compatible titles, so I've been trying to recreate this effect in ScummVM. I tried using the "staging" shaders directly in it but ScummVM doesn't seem to work with the .glsl format yet. I've tried to recreate the effect via other shaders in ScummVM but so far unsuccessfully.

Been delighted with the tremendous progress that ScummVM has gone through so that we could even get to this point where shaders work, something that wasn't even possible just a few years ago so thank you for all the wonderful work.

If anyone has experience with or running double scanlines with the existing CRT shaders I would love to know how the effect is achieved. Thank you.