[maemo-developers] Fremantle OpenGL wrapper?

[From: Qole]

That's quite disappointing.

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."
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