I've just started using HLSL in MAME to get that classic scan line look, and it works a treat — most of the time.
However, I'm trying to get my
channelf games to quadruple their scan lines (like the original console did). By that I mean: each row of pixels occupies four scan lines on the CRT, as you can observe by fullscreening this video.
I'm not having any luck, though. Mine comes out looking like this instead. (The snapshot mechanism screwed up the aspect ratio here, but you can see what I mean.) The effect clearly thinks: "one row of pixels = one scan line, what's the problem?". Ha. At 58 pixels vertical, that's not gonna cut it.
prescale option doesn't do anything to help, even though it seems like it should be exactly what I want.
(I'd also be interested to know where to put any config file(s) that applies only to
channelf. Obviously I don't want what I'm asking for here done elsewhere.)