[SDL] The multiscreen question again

David Olofson david.olofson at reologica.se
Tue Jul 2 08:44:00 PDT 2002

On Tue, 2/07/2002 12:54:54 , Andrew Straw <andrew.straw at adelaide.edu.au> wrote:
>I know these questions have been asked in the past, but it seems to me 
>that they're only going to become more frequent (that new card from 
>Matrox supports 3 screens!) and I can't remember the answer:

..and it seems like the high resolution capabilities will be at least as good as on their previous cards. (That is, usable with serious analog monitors.)

Can't wait to get my hands on one. :-)

>What are the current thoughts on, and the status of, opening multiple 
>screens and being able to position windows in the window manager with 

Well, IIRC, someone hacked a half-way solution (video, but not event handling) for Solaris or something. I was about to port it to Linux, but got sidetracked. (Frankly, I can't even remember if I actually did anything with it or not... *heh*)

Anyway, this is most probably not going into the mainstream SDL 1.2.x, at least not unless we can figure out some ingenious way to add it without breaking compatibility in either direction.

> My project needs multiscreen and window positioning capabilities 
>on win32, Mac OS X, and X11, and I'm going to have to switch to a 
>different library or hack my own solution unless SDL goes this way. I 
>know that SDL target platforms include consoles, PDAs, and probably 
>fancy new refrigerators, so I can understand if this can't be included 
>as standard SDL, although it seems like it would be useful for many 
>people currently using SDL.

Apart from  the API and the implementation issues on some platforms, this is not a problem. To deal with targets w/o window managers, either provide generic SDL hooks for window managers, so that applications can provide their own WM (or some simple build-in default WM) for fullscreen modes, or just report an error if an application asks for stuff that requires a WM, or tries to open a secondary display on a single headed system.

>Can anyone recommend a course of action? The code I currently use from 
>SDL is fairly minimal. It is only used to open a window for OpenGL and 
>to get keystrokes, so moving to a different solution wouldn't be too 
>difficult, and would perhaps be a better fit, since I don't need any of 
>SDL's non-OpenGL 2D capabilities.

Well, maybe you should look for some wgl/glx/... wrapper instead?

I would say SDL offers plenty of useful stuff in the "system interfacing" area, especially for portable apps, but if you don't need any of it...

> (Although glSDL could be handy...)

IMHO, if you're using OpenGL, glSDL isn't really for you. glSDL is primarilly designed to run normal (2D) SDL applications on OpenGL, to make serious hardware acceleration available on more platforms.

That said, maybe the tiling stuff is handy enough to put in a separate library, redesigned for cooperation with OpenGL code? (I think it's too low level to be truly useful for that, but I might be missing something.)


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