27 October, 2007

accelerated rendering

Of course we have some experts in this area in the KDE community (zack is well known, but I wouldn't forget about Mosfet or the people working on KWin.

Now my understanding of this stuff (being not a developer) is always very limited - which does nothing to lower my interest in them... So when I read this blog on the gnome planet, I found it very interesting. I mean, it has pretty pictures, you know... And hardware accelerated rendering, preferably using openGL for everything (or at least more than we do now) is something I'd love to see - it really sounds like a big thing in terms of performance ;-)

Now the person who wrote this blog isn't very positive about this, but I agree with some of the comments there - OpenGL probably won't go away. Or would it be possible to integrate it with toolkits? This blog by Daniel Molkentin talks about using just the normal Qt api, yet the drawing goes through OpenGL. Sounds like neat, but what about all the other drawing in KDE/Qt?

The point of this blog is mostly that I haven't read about lower-level stuff like this for a while in the KDE blogosphere, and I'd love to see that change ;-)

How's the status of Arthur? Animations KDE4 are still kind'a disappointing in some areas - at first I blamed compositing (and it does make matters slightly worse, yes, but just slightly). Take the run dialog - it has an animation when you click options. Lovely, but it never works smooth, even the 100th time (you'd say it has cached stuff, and it has, but it's not enough). It's not just having to resize the window (even though that's bad), but even after that it's not exactly smooth.

And the background gradient in Oxygen has the disadvantage you often see a plain background flashing when resizing or animating things. As I see the CPU usage max out, I wonder if the GPU is used for any of these things - and if not, why not? Where's the bottleneck? X, Qt, other infrastructural stuff, or can't the GPU help at all?

So, who's involved in these things, and willing to write about them - what can we expect for KDE 4.0 and the future? Will these things be solved, is 3D hardware acceleration gonna help us anytime soon? When I see the animations in Vista - they're very smooth, and CPU usage keeps low, so it seems to me they've got the issue solved, haven't they?


  1. ...not to mention Leopard ;)

  2. Well, resizing is crappy in both Vista and OS X too, last I checked. Does compiz have the same problems for you as kwin+effects?

  3. I'd bet it's your gfx-card drivers. They probably don't support EXA, or you haven't turned on compositing, or something else wrong. The animations work pretty flawlessly here

  4. Leo s: Hmm, maybe I should check again, but I recall it as very smooth in windows...

    @anonymous: I do have compositing on, proprietary NVIDIA drivers. How flawlessly are they? When I resize dolphin horizontally, I see some darker-grey flashes on the right of the breadcrump bar (maybe it's just that one which is slow?)

    KRunner is pretty bad as long as it's resizing its window (eg first time you click more options) but the second time it's almost fully smooth.

  5. @jos: yeah, known issue with krunner. it's equal parts X and Qt to blame there. Qt 4.4 will help with moving the widgets around, but X will likely still get in the way.

    i don't plan on leaving krunner as is for 4.0, though.

  6. ah .. as for dolphin as well .. you ask for people to blog about this stuff, but you aren't keeping up with the blogs evidently.

    e.g. http://labs.trolltech.com/blogs/2007/08/30/say-goodbye-to-flicker-aliens-are-here-to-stay/

  7. let's try that again, but this time... with a link

  8. I think I'm the only who goes backward then (i.e. trying pure software renderer):

  9. @aaron: hey, that's several months old already ;-)
    Would the flicker I talk about be fixed by Qt 4.4, then? In that case - ignore what I've said ;-)

    1. why aren't you on planetkde.org?
    2. yeah, maybe. Well, providing it as a backup strategy would be cool, but using OpenGL (maybe possible through Qt) would be neat to have... The CPU has more to do. I often test KDE 4 apps while compiling (heavily) as my dualcore otherwise would be a bad example for the 'average' pc -> eg my little 500 mhz laptop. Where resizing sure isn't smooth ;-)

  10. jos:
    1. according to clee, planet doesn't like my blog/feed :-(
    2. sure 100% agree that opengl is the right way to go. just don't forget old machine, portable device etc etc.

  11. @ariya: I've added you to akregator for myself, I probably blog about your blogs when they appear :D


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