[Scummvm-devel] Features and graphics modes

[Torbjorn.E.Andersson at tietoenator.com]

Marcus Comstedt <marcus at mc.pp.se> wrote:

> Ok, some questions about the new OSystem interface:
> 
> * How is kFeatureAspectRatioCorrection supposed to work?  Since I use
>   a textured quad to display the screen on the Dreamcast this sounds
>   like a feature I could implement easily, but how do I know which
>   aspects to convert from and to?  The interface only says that
>   correction should be "on" or "off".

The reason for aspect ratio correction is probably best described at
http://www.aarongiles.com/scumm/index.html though of course Aaron is
describing his own updated SCUMM engine, not ScummVM. Basically, it's
a trick to allow the games to cover the entire screen, even if they're
running at a resolution that the screen/graphics card doesn't support.

(I also find it useful in windowed mode, but I assume that's not a
concern on a Dreamcast.)

The SDL backend hardwires this to mean that if the original image is
200 pixels tall it can be stretched to 240 pixels.

So if the Dreamcast already uses the entire screen - I wouldn't know
about that since I've never even seen a Dreamcast - then you won't have
to worry about aspect ratio correction. At least, I don't think there
will be much requests for running the games in "letterbox" mode. :-)

Torbjörn Andersson

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