On Thu, 18 Dec 2008 17:58:19 -0200, Nicolas Alvarez wrote:

> Jim Henderson wrote:
>> The thing that I like about it is that everything is a texture - it's
>> an interesting way of looking at a standard display, because you can do
>> things like enhanced zoom or the rotating cube with very little CPU
>> overhead, so it seems.
> 
> The idea is that zooming in doesn't use any more CPU/GPU than not doing
> it. When looking at the normal screen, it's already applying the
> identity transformation matrix to everything anyway :) Changing the
> matrix to do some scaling costs nothing.
> 
> (of course, interpolation during scaling does cost some GPU)

Yes, and I think that's an outstanding way to do it.  It' s nice to see 
my CPU not being used for things like that. :-)

The interesting thing is that if I start playing a video in mplayer and 
switch to fullscreen, then increase the playback speed (all this with 
audio turned off), the playback speed maxes out sooner than if I leave it 
in a window and zoom in on it.  It's probably the mplayer scaling that 
causes that, but it's interesting that I get better performance letting 
xgl handle the zooming to full screen.

Of course it makes sense, mplayer uses its own scaling and not xgl's.

Jim

Post a reply to this message