[maemo-developers] Fremantle OpenGL wrapper?

[From: Kimmo Hämäläinen]

On Wed, 2009-06-03 at 09:17 +0200, ext Qole wrote:
> That's quite disappointing. 

Don't worry, hildon-desktop will be open-source, so you can fix it
yourself ;)

-Kimmo

> 
> I'm looking forward to seeing further news about "game mode," I guess.
> 
> 2009/6/2 Kimmo Hämäläinen <kimmo.hamalainen at nokia.com>
>         Hi,
>         
>         On Wed, 2009-06-03 at 00:53 +0200, ext Qole wrote:
>         >
>         >
>         > On Tue, Jun 2, 2009 at 3:04 PM, David Greaves
>         <david at dgreaves.com>
>         > wrote:
>         >
>         >
>         >         I understood that GL wasn't going to be available to
>         the apps
>         >         on the device...
>         >         something about the window manager permanently
>         taking the only
>         >         viewport?
>         >
>         >         I am not sure if this is a beta-phase bug or a
>         hardware or
>         >         GLES issue.
>         >
>         >         David
>         >         --
>         >         "Don't worry, you'll be fine; I saw it work in a
>         cartoon
>         >         once..."
>         >
>         >
>         > I think you are referring to the following two posts, both
>         by Kimmo
>         > Hämäläinen. I don't believe they say that GL won't be
>         available, but
>         > that there will be a performance hit
>         
>         
>         OpenGL is not available in the device but OpenGL ES2 is.
>         Notice that
>         this is a big problem when porting OpenGL applications from
>         the desktop
>         PC world.  Some kind of OpenGL to OpenGLES conversion layers
>         are
>         possible but with some FPS cost, I assume.
>         
>         >  because the apps will have to go through Hildon-Desktop to
>         render,
>         > rather than rendering directly.
>         
>         
>         Yes, about 30% penalty with the compositor, but I'm working on
>         "non-
>         composited" or "game mode" for hildon-desktop that allows
>         shutting down
>         the compositor and rendering directly to the screen (without
>         killing
>         hildon-desktop).  I still need to get it working with dialogs
>         and menus
>         popping on top of the non-composited application, but I guess
>         it'll work
>         in the end somehow.
>         
>         BR; Kimmo
>         
>         
>         >
>         > http://lists.maemo.org/pipermail/maemo-developers/2009-
>         > March/018639.html
>         >
>         >         As Kate has already proven, multi-context works.
>         >         But as long as you have hildon-desktop running in
>         the
>         >         background, you
>         >         will not render directly to the screen even if you
>         use
>         >         Clutter/QtGraphicsView/EGL+OpenGLES2.0/whatnot in
>         your
>         >         application. When
>         >         hildon-desktop is running, it is the only one
>         drawing on the
>         >         screen
>         >         (with the exception of XVideo). So, killing hildon-
>         desktop is
>         >         the only
>         >         way to get direct rendering to the screen at the
>         moment. (We
>         >         might have
>         >         something more elegant for this in the future...)
>         >
>         > http://lists.maemo.org/pipermail/maemo-developers/2009-
>         > March/018645.html
>         >
>         >         Keeping the compositor around has some performance
>         impact,
>         >         because after
>         >         the application draws to an offscreen pixmap (the
>         window), the
>         >         X server
>         >         sends Damage events (saying "this part of the pixmap
>         changed")
>         >         to
>         >         hildon-desktop, and hildon-desktop asks the 3D HW to
>         use this
>         >         pixmap in
>         >         a OpenGL texture and draw it to the screen. So,
>         there is some
>         >         extra
>         >         delay (maybe 10-25ms) after the application's
>         drawing is
>         >         visible.
>         >
>         >         Second implication is that you cannot use HW
>         accelerated
>         >         zooming and
>         >         moving of textures for the whole graphical pipeline.
>         You can
>         >         use it for
>         >         drawing into your window, but when hildon-desktop
>         draws to the
>         >         screen,
>         >         it cannot use it (e.g. it cannot say "move this
>         content to
>         >         there"). It
>         >         will just get a big damage area that is updated by
>         updating
>         >         the OpenGL
>         >         texture content.
>         >
>         >         Third implication: to save memory, we are using the
>         texture-
>         >         from-pixmap
>         >         GL extension to allow the X server and 3D HW share
>         the pixmap
>         >         data. This
>         >         means that while 3D HW is accessing the pixmap data
>         (while
>         >         transferring
>         >         it to the 3D chip), X server cannot access it. Thus,
>         while the
>         >         compositor is updating the screen, it is slowing
>         down X
>         >         drawing.
>         >         However, it's not mandatory to use texture-from-
>         pixmap, but
>         >         then you are
>         >         paying the price in increased RAM usage.
>         >
>         >
>         >
>         >
>         > --
>         > enthusiast, n. "One whose mind is wholly possessed and
>         heated by what
>         > engages it; one who is influenced by a peculiar fervor of
>         mind; an
>         > ardent and imaginative person."
>         
>         
> 
> 
> 
> -- 
> enthusiast, n. "One whose mind is wholly possessed and heated by what
> engages it; one who is influenced by a peculiar fervor of mind; an
> ardent and imaginative person."