[SDL] Re: moving screen when u change resolution

Bob Pendleton bob at pendleton.com
Mon Jan 31 07:50:44 PST 2005


On Fri, 2005-01-28 at 20:27 -0700, Rainer Deyke wrote:
> Jon Colverson wrote:
> > As mentioned at:
> > http://www.libsdl.org/cgi/docwiki.cgi/SDL_5fenvvars
> > neither users nor applications should be relying on the
> > environment variables; they aren't part of the API.
> 
> If there was no need to access this functionality, these environment
> variables wouldn't exist in the first place.  That said, I wouldn't mind at
> all if these environment variables were replaced with functions in the C
> API.
> 
> > SDL_VIDEO_CENTERED looks like the only variable which
> > provides potentially portable functionality, and as such,
> > I think it would be a good candidate for being added to
> > the C API (presumably as a flag for SDL_SetVideoMode(),
> > which I believe could be added without breaking binary
> > compatability in any direction).
> 
> I'd like to see at least the following in the C API:
> 
> SDL_VIDEODRIVER (plus some way of enumerating available video drivers)
> SDL_VIDEO_CENTERED
> SDL_WINDOWID

I'd be surprised if that one every became available through a C API. It
is a hack that is only supported by a small number of video drivers.
Making it an environment variable means that only the drivers that
support it need to even be aware that it exists. OTOH, making it a
standard part of SDL means that *every* driver has to have code to
handle it, even if all the code does is return an error message. 

The same thing is true of the SDL_VIDEO_CENTERED but a flag is a lot
easier to ignore than an API.

> SDL_AUDIODRIVER (plus some way of enumerating available audio drivers)
> 

In most cases video and audio driver selection is moot. You rarely have
more than one choice. When you do it is usually the case that one is
automatically used as a fall back for a better driver. Or, in some cases
the alternative driver requires special permission to use. Consider the
difference between the X driver and the other Linux drivers. Anyone can
run an SDL_X11 program, but using the DGA requires you to have root
privileges. On windows, when would you use the DIB driver if you could
use the DirectX driver?

		Bob Pendleton






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