Le Tue, 22 Feb 2011 22:11:27 +0000,
Fons Adriaensen <fons@linuxaudio.org> a écrit :
> > 2) more and more apps able to take advantage of v-blank sync to
> > reduce computational load due to unnecessary redraws. instead, the
> > whole system will be a lot like a video-framebuffer version of
> > JACK: the vblank interrupt arrives. everything with a surface gets
> > a chance to redraw if it needs to, the surfaces are composited
> > together, and boom, its on the display.
>
> Two remarks on this:
>
> 1. Syncing updates to the video frame rate of course makes sense,
> and there is no reason why it couldn't be done in X. All it takes
> is some support from the driver to generate an event at the right
> time.
>
> 2. But at the same time this is sort of backwards. There is no reason
> today why a computer display should be driven by a 'video' signal that
> refreshes the complete screen at a fixed rate. *That* itself is very
> old technology and completely useless in this age.
Another problem is the hardware. All the PC video cards are video
driven. That imply than the card have to refresh the whole screen in
order to change one pixel. That is not old technology, that is PC
technology. At the same time than the first PC was computers like the
Amiga or the Atary.
In the Amiga, the video card was vectorial, to change one pixel, all
that was needed was the new pixel value and its x y coordinates. To
change a part of the screen, the Amiga was using vectorial
objects called sprites. So, even for complex visual objects, the
computational time was much lower than with the video approach, and the
2D on such old machines is still competitive against the 2D on the most
powerful PC of today.
At that time, 3D was almost non existent. To develop the 3D
capabilities, most efforts from the manufacturers was spend on
improving the video based cards. Now, the situation is than the 2D part
of a video card is so little than the manufacturers are considering to
remove it and use the 3D part to get the 2D from the card.
I don't get the advantage of this approach for a workstation. A
workstation is not about 3D gaming but about making some work. 3D
cards are very hungry for electricity, and they will be an overkill for
anyone that is not working on some kind of 3D development. The
electricity providers will certainly like them very much, but my wallet
and the environment don't like them.
So, I think than a complete discussion on that matter should include
the hardware part, that is how to make power and computational
efficient 2D video cards.
Dominique
>
> Ciao,
>
-- "We have the heroes we deserve." _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-devReceived on Thu Feb 24 04:15:03 2011
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