
It gives a subtle ‘aperture grill’ effect on the image, softening the edges a little, without blurring. This last bit is optional, but I’ve had good results with the dotmask retroarch shader. This keeps them visible, but doesn’t darken the image (much). If you look closely at the screen, you might see a few instances where the lines aren’t exactly lined up with the pixel edge, but it seems very rare, and unnoticeable (to me!). How do you create a scanline image which fits 224 scanlines, in 1080 pixel high image? The maths doesn’t work! What I’ve done is tested out a variety of image scaling techniques, and believe I’ve found the best fit with ‘linear’ scaling. What about scanline overlays? These have the same issue. If you change your Retroarch render resolution to ‘output’ in the launch menu (press ‘x’ on a keyboard when a rom is loading), it will render at your output resolution (1080p), and suddenly scaling is much better! I can’t notice any thick rows of pixels at this resolution.

This explained the scaling issues to me – in trying to fit 224 into 480, it has to DOUBLE the size of the occasional row of pixels. How come I’m noticing one row of pixels being 1/1080 bigger than another?! This set me off…īy default in Retropie, Retroarch runs at 640×480, regardless of your video output setting. Option 2 is sometimes acceptable – eg, some games will treat the top and bottom extremes as potentially being hidden on some TV sets, so crucial information won’t be displayed there (eg, Mario Bros on the NES) This works for many people and is absolutely the best way to get a 100% correctly scaled scanline image on a 1080p screen. Option 1 is detailed in patl’s thread linked above. turn off integer scaling and let the emulator work it out, BUT this ends up with ugly thick rows of pixels where they’ve clearly been expanded at a different size to their neighbours, to make the maths work.scale each pixel to represent 5×5 1080p pixels (ie, 5*224=1120 pixels high), BUT this means you will cut off the top and bottom of the image, which often contain important score/credit info.scale each pixel to represent 4×4 1080p pixels (ie, 4*224=896 pixels high), BUT this leaves you with black borders on the top and bottom of the image.With a modern 1080p screen, you have an issue where there’s no way of dividing the vertical number (224) in to 1080.

Most console systems and arcade games from the 80s until the mid 90s, output in ‘raster’ resolution, which seems to almost always be 320×224. Meaning no disrespect to patl and co for their excellent work achieving pixel-perfect scaling and scanlines in the other threads (eg ), I’ve been trying to find a way to get a nice scanline effect, AND an image that fills the entire vertical of a 1080p screen, without minimal distortion to either, and I think I think I’ve finally got something that I can live with. Most old consoles have an amount of (usually) invisible ‘overscan’ which is a side-effect of CRT tvs, but it seems that most emulators crop that out automatically, leaving you to worry about the ‘visible’ bit only. NOTE: when talking about console ‘resolutions’ below, I’m talking about the resolutions displayed by the emulators.
