[Scummvm-devel] System independent widescreen support

Bertrand Augereau bertrand_augereau at yahoo.fr
Tue Apr 28 18:29:01 CEST 2009

Hi Max,

> Thus, if the video card and displays are
> "honest", about what resolutions they actually
> support, there is no problem. As soon as they start
> "lying" resp. are simply misconfigured, we run
> into problems. Like, ScummVM not starting up because it sets
> an unsupported screen resolution (note that SDL and hence
> ScummVM only tries to set screen resolutions which the OS
> tells it are OK... *sigh*).

The notion of "supporting" a resolution is indeed fuzzy for an OS/hardware/driver combination.
There's not really a well defined semantics that is agreed upon so I guess it makes sense for programs to allow a wide choice of configurations... provided the default is good enough so the user isn't completely baffled.

> Now, since often graphics card or screens are indeed
> misconfigured, it would be conceivable to add an option to
> ScummVM to "force" a certain actual resolution
> (like 1024x768) and then setup our actual screen surface as
> a subsurface of that. I.e., add two options to the config
> file "actual_screen_width" and
> "..._height" (better names are welcome ;), and
> then modify the SDL backend to honor those if present.
> Patches on the patch tracker for this are welcome.

Ok I'll be glad to give it a shot. Better names are not guaranteed though ;)
But are you sure this is the best option?
If you change the scaler, the height varies and then you probably want a different resolution.
I think a "desired_resolution_ratio" would be better. It applies the scaling factor, then determines what is the smallest resolution that fit the ratio and try to use it. It would be more orthogonal I suppose.
(There might even be non-portable ways to get a default value for different platforms).

> What is going on here is that in the old days, monitors did
> not have square pixels, rather, they were a bit higher than
> wide. Modern displays, however, have square pixels. As a
> result, the graphics of many old games look vertically
> squashed without ASR.

Ok, I was wondering if the aspect preservation did or should try to go any further than this. But it seems it does just this one thing so it's a good thing.

Thanks for the answer, as always,


PS : Sorry for replying to old threads, I don't see this kind of stuff in my webmail.

PPS :  Check R.U.S.E., http://www.rusegame.com, my next game that plays nice with widescreen :p


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