Option to only draw every other scanline

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    Requesting the option to only draw every other (even or odd) scanline. The use case is for pre-line-multiplied content (particularly in 480p/720p/1080p).

    For example: Axiom Verge on the Wii U contains 270p pixel graphics which are 4x multiplied by the console into a 1080p output. There is no way currently to use the OSSC to add a scanline on each of the 270 lines, but this proposed feature would allow it.

    Note that the existing “Sl. alt interval” option does NOT accomplish this. The “Sl. alt interval” option does nothing for 720p and up source signals, and for 480p sources it seems (in line 2x mode only) to change from a scanline pattern of 10101010 to 11001100. I could imagine that was the desired behavior, but it does not satisfy the feature I’m requesting here.


    Hi xyga here.

    Created an account just to say I’ve been hoping for a similar feature, but for columns ! ^^

    Reason: in x4 and x5 the kind of CRT imitation we get is a look similar to that of high-TVL like monitors, not looking like standard definition consumer tellys.

    So one would say “why not output in x3 if you want that ?”, and I would agree but in most cases the issue is that the display’s built-in scaling – unlike in x5 1080p mode on my compatible monitor which is 1:1 – easily creates ugly artifact/patterns.

    The only way to mitigate the issue is by tweaking ADC but it means making the picture way too dark.

    Optimized modes also aren’t fit for this, so it’s draw only every other scanline while in generic modes that’s needed.
    For me it is the only thing that’s missing on the original OSSC.

    (Yep I’ve been bothering marqs a few times about it on shmups some time ago. ^^ )


    Sorry to UP this but I’d like to know ultimately if there’s a final word on this; option to draw only every other scanline or column.
    (my personal expectation is for the latter especially for x5 mode)
    marqs you were saying it might be easy to do but maybe it’s not after all ?


    Another great use case for this feature would be with the Game Boy Interface outputting its OSSC-specific 360p mode. Since that’s a pre-linedoubled image, even-only (or odd-only) scanlines would make for a nice overlay. Same idea with horiz+vertical (grid pattern), it’d look awesome if the every-other-on option were possible.


    One more: recently I’ve tried the pc engine mini (with a hdmi>vga dongle) and I thought “DAMN if only we had that”.
    (the mini’s default crt effect is terrible)

    Draw only every other line and/or column is missing sorely indeed. Marqs sounded optimistic about a year ago so I don’t know why the silence about it, while requests for fairly obscure cases get attention.
    Originally I though such added feature to the scanlines engine would find few use cases, but in fact it should be quite useful in many places, like I was also contemplating all the things I could do with the 360’s 2D library.

    Welp, fingers still crossed!


    So, still not a word on this? *sob*

    It would be great for producing a standard res crt look in x4 and x5 (every other column), and a fantastic feature for Mini consoles (every other line) among other things.

    If a reason for the silence is that the idea is reserved for the Pro, well that’s a shame.

    I doubt marqs and contributors don’t see the benefits of such a feature, maybe a lot of users are unaware but they’d definitely get the reason why we wish for it after the results would be demo’ed.


    Just realized that for the desired use case with 3x prescaled content (usually a 720p signal), there’d need to be an option to draw a scanline on every third line.

    Another way to regard this functionality would be a downscale followed by an upscale (different upscale/downscale factors of course), with scanlines applied to the final output. If the OSSC Pro can accomplish that “chain” of processing, it would give the same end result.

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