[Bug 22045] Re: [breezy+dapper] gnome-screensaver doesn't perform as well as xscreensaver with the same hacks.

Bart Hartgers bart.hartgers at gmail.com
Wed Apr 5 09:09:01 UTC 2006

Hi Oliver (and others),

Don't know if this is the right platform for this, but:
In that case, I might be able to help. I've a radeon 9200 in my desktop that has the same problem, and I am halfway done with a patch agains 2.14 to fix this on my system. Naturally, I would like my fix to be included into gss, so I have a few questions about how to make the fix exactly.

But first the problem:
The problem is that the default X visual is not double-buffered from a GL point of view. So when a GL screensaver is run on a gtk_window (via the XSCREENSAVER_WINDOW environment-variable), you end up with flicker.

xss solves this by asking GL for the number of the best visual and uses that instead of the default one. This is done via xscreensaver-gl-helper, so that xss does not directly depend on OpenGL.

I think I've figured out how to create a gtk_widget using a non-default visual and I propose to use that visual for all screensavers, if it is available.
Non-GL screensavers probably don't mind running on a different visual, otherwise we need a UseGL flag or something in the .desktop-files.

But to get the number of the correct visual I can either:
- use xscreensaver-gl-helper directly
- roll my own gss-gl-helper (rip it out of xscreensaver), or 
- include the code into gss, introducing a dependency on OpenGL.
I don't know which is the best thing to do from a gss point of view.

Any comments or suggestions?

[breezy+dapper] gnome-screensaver doesn't perform as well as xscreensaver with the same hacks.

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