A Great Feature from DOSBox CVS

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Great Hierophant
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Joined: Mon Mar 12, 2007 1:44 am

A Great Feature from DOSBox CVS

Post by Great Hierophant »

One, if not two of the DOSBox CVS support this great feature that should really be added to SCUMMVM. The feature essentially scales the pixels in a one-to-one manner to fill the screen. This is especially useful for those of us with LCD monitors, which are fixed-resolution devices.

Most, if not all the games SCUMMVM supports display in a 320x200 resolution. Most people with LCD screens have screens with a native resolution like 1280x1024, 1600x1200, 1920x1200, 2560x1600. There are other resolutions, but these are the most suitable for 320x200 graphics. What these DOSBox CVSes do, when using direct3d for output, is to expand the graphics to the maximum extent possible to fill the screen but always multiplying the pixels by whole numbers.

320 x 4 = 1280, 200 x 5 = 1000
320 x 5 = 1600, 200 x 6 = 1200
320 x 6 = 1920, 200 x 6 = 1200
320 x 8 = 2560, 200 x 8 = 1600

The first two give something close to the pixel ratio of a CRT monitor in full-screen. The second two give a true rectangular pixel aspect ratio. However, they fill or virtually fill the entire screen, making for a better experience, sharp pixels instead of fuzzy ones.

Other resolutions will still have windowbox bars in this manner:

320 x 3 = 1024, 200 x 3 = 600 (1024x768)
320 x 4 = 1280, 200 x 4 = 800 (1440x900)
320 x 4 = 1280, 200 x 5 = 1000 (1400x1050)
320 x 5 = 1600, 200 x 5 = 1000 (1680x1050)

I think this would be a great feature to add to scummvm
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Post by clem »

I think you'll have better chances with that if you post it on the feature request tracker.

thinking back there has always been kind of reluctance to add additional scalers, though
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Post by Dark-Star »


especially the x5/x6 'hybrid' scaling would be great for 1600x1200 displays... maybe even with a "scanline" option (rendering the 6th line 50% darker, or 5th and 6th line, whichever looks better)...


Would IMHO look a lot better than the "fix aspect ratio" option
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Post by Kroc »

Aye, auto sensing would be useful for me, getting things to look right in 1440x900 is not easy, and if you use the wrong size in ScummVM it just crashes when you start the game, leaving screen fitting down to trial and error most of the time.
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Post by cappuchok »

There's also an option in most graphics cards' control panels to set scaling methods on flat panel displays. For this to work, though, it's best to have the screen connected through DVI.
I must say I'm VERY happy with my DVI-connected 1280x1024 screen which, through some magic of Nvidia's fixed-aspect scaling, never shows a distorted screen ratio regardless of the resolution used. :D
PS, fixed aspect ratio timings didn't work nearly as well or reliably when connected through a regular VGA cable.
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