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Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window
From: |
Stefano Stabellini |
Subject: |
Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window |
Date: |
Mon, 08 Sep 2008 14:51:21 +0100 |
User-agent: |
Thunderbird 2.0.0.14 (X11/20080505) |
Jamie Lokier wrote:
> Anthony Liguori wrote:
>> I'd like to see if it really makes a difference performance wise to
>> render with OpenGL. I've had good results in the past using software
>> bilinear interpolation to do scaling. If OpenGL doesn't provide a
>> measurable performance advantage, doing it in software may be the right
>> thing to do.
>
> Software interpolation, especially bilinear or other filter, is
> relatively slow if you're expanding a lot of pixels e.g. 640x384 to
> 1920x1200. OpenGL will surely beat it.
>
> On the other hand, OpenGL can to be relatively slow (in my experience)
> if there is no colour conversion and scaling to do and X11-SHM would
> be a straight 2d blit on the server side.
>
> In principle OpenGL should as fast as the 2d blit or faster on
> implementations where the image in client app's memory is a
> memory-mapped texture, but that seems to be still a work in progress
> on BSD and Linux. DRI2 was dropped this summer because the TTM
> texture memory manager was ousted in favour of the GEM texture memory
> manager... and they haven't caught up with each other yet. You need
> some kind of good shared texture memory to get great speed out of
> OpenGL displaying a texture which is being constantly updated by the
> client app.
>
> Imho, if there is an OpenGL backend (overlaid on SDL, Xlib, or
> whatever), it should be a switch, for the next few years probably
> defaulting to X11-SHM (or plain X11 when remote), and changing the
> default to OpenGL in a few years when that's working really well
> everywhere.
>
I agree with you on everything.
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, (continued)
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Stefano Stabellini, 2008/09/05
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Daniel P. Berrange, 2008/09/05
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Stefano Stabellini, 2008/09/05
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Anthony Liguori, 2008/09/06
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Stefano Stabellini, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Jamie Lokier, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window,
Stefano Stabellini <=
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Jamie Lokier, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Daniel P. Berrange, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Gerd Hoffmann, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Jamie Lokier, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Gerd Hoffmann, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Jamie Lokier, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Gerd Hoffmann, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Anthony Liguori, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Gerd Hoffmann, 2008/09/08
- Re: [Qemu-devel] [PATCH] opengl rendering in the sdl window, Jamie Lokier, 2008/09/08