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Rendering to file

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Dmitry Shulga

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Apr 7, 2003, 4:57:46 PM4/7/03
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Hello!

Is there a way to render everything into a file instead of the frame buffer?
I know it is possible but with a strightforward approach it takes forever
whereas when it is rendered normally, it is just nothing. I more of less
understand why but it does not make me happy. I do want to exploint graphics
hardware instead of just software rendering.

In reality, the task is a remote rendering, which means just starting some
application somewhere on the remote computer and getting an image or a bunch
of them as a result. Any help will be appreciated. Any ideas are wellcome.
Even crazy ones.

Dmitry

Jason Allen

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Apr 7, 2003, 9:47:02 PM4/7/03
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You can render each frame onscreen then read it back using glReadPixels and
save it to disk.

Jason A.
"Dmitry Shulga" <sch...@erc.msstate.edu> wrote in message
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Dmitry Shulga

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Apr 8, 2003, 2:28:15 AM4/8/03
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"Jason Allen" <jra...@yahoo.com> wrote in message
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Well, I am sorry to say that but you are careless. Read my post again.

-d

Michael Vittrup

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Apr 8, 2003, 2:29:40 AM4/8/03
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On Mon, 7 Apr 2003, Dmitry Shulga wrote:

>Is there a way to render everything into a file instead of the frame buffer?
>I know it is possible but with a strightforward approach it takes forever
>whereas when it is rendered normally, it is just nothing. I more of less
>understand why but it does not make me happy. I do want to exploint graphics
>hardware instead of just software rendering.

Use glReadPixels to store your framebuffer in system memory, and write
from system memory to file. Easy and straight forward ,)

// Michael

fungus

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Apr 8, 2003, 3:57:23 AM4/8/03
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Dmitry Shulga wrote:
>
>
> Well, I am sorry to say that but you are careless. Read my post again.
>


If you want to render with the graphics card then you
have to render *on* the graphics card.

However, don't render to a backbuffer because that
causes many problems and forces you to open a window.
Render to a pbuffer instead (google for it).


--
<\___/>
/ O O \
\_____/ FTB.

Phil Frisbie, Jr.

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Apr 8, 2003, 11:41:32 AM4/8/03
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Dmitry Shulga wrote:
> Hello!
>
> Is there a way to render everything into a file instead of the frame buffer?

Maybe with software rendering, but it depends on the platform you are using.
Linux, Solaris, Windows, other?

> I know it is possible but with a strightforward approach it takes forever
> whereas when it is rendered normally, it is just nothing. I more of less
> understand why but it does not make me happy. I do want to exploint graphics
> hardware instead of just software rendering.

If you want to exploit hardware, then you must render to the back buffer or a
pbuffer, then use glReadPixels() to copy the pixels to memory so that you can
save it in whatever graphics format you need.

> In reality, the task is a remote rendering, which means just starting some
> application somewhere on the remote computer and getting an image or a bunch
> of them as a result. Any help will be appreciated. Any ideas are wellcome.
> Even crazy ones.

Does this remote application need to be silent/invisible? If so, then pbuffers
are probably your bet choice.

> Dmitry

--
Phil Frisbie, Jr.
Hawk Software
http://www.hawksoft.com

Dmitry Shulga

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Apr 8, 2003, 8:00:56 PM4/8/03
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"Dmitry Shulga" <sch...@erc.msstate.edu> wrote in message
news:3ulka.107492$R25....@fe10.atl2.webusenet.com...

Thanks everybody who mentioned p-buffer term. It is really what I need. For
those who is interested, here is a link:

http://developer.nvidia.com/docs/IO/1293/ATT/GDC01_PixelBuffers.pdf

Dmitry

Gib Bogle

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Apr 8, 2003, 9:30:57 PM4/8/03
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Dmitry Shulga wrote:


> http://developer.nvidia.com/docs/IO/1293/ATT/GDC01_PixelBuffers.pdf

I'm interested in this too, and I'd like to be able to do it on Linux.
That paper describes the procedure in W32, but regarding Linux just says
"Supported in GLX 1.3". I understand that the recent nVidia drivers for
Linux do support GLX 1.3, but I don't know how to implement the
procedure described, which uses WGL_ARB_pixel_format and
WGL_ARB_pbuffer. Can someone explain this?

Gib

Jason Allen

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Apr 8, 2003, 9:45:46 PM4/8/03
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If you want to see how to implement pbuffers in Linux, check out the pbuffer
class used by NVIDIA devtech demos:

http://cvs1.nvidia.com/DEMOS/OpenGL/inc/shared/pbuffer.h
http://cvs1.nvidia.com/DEMOS/OpenGL/src/shared/pbuffer.cpp

The Linux section starts near the middle, search for "if defined(UNIX)".

Jason A.

"Gib Bogle" <bo...@ihug.co.nz> wrote in message
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Gib Bogle

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Apr 9, 2003, 2:04:57 AM4/9/03
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Jason Allen wrote:

> If you want to see how to implement pbuffers in Linux, check out the pbuffer
> class used by NVIDIA devtech demos:
>
> http://cvs1.nvidia.com/DEMOS/OpenGL/inc/shared/pbuffer.h
> http://cvs1.nvidia.com/DEMOS/OpenGL/src/shared/pbuffer.cpp
>
> The Linux section starts near the middle, search for "if defined(UNIX)".

Thank you!

Gib

Michael Knapp

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Apr 9, 2003, 6:41:16 AM4/9/03
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Dmitry Shulga wrote:
> Hello!
>
> Is there a way to render everything into a file instead of the frame buffer?
> I know it is possible but with a strightforward approach it takes forever
> whereas when it is rendered normally, it is just nothing. I more of less
> understand why but it does not make me happy. I do want to exploint graphics
> hardware instead of just software rendering.

In Microsoft Windows it is possible to render to a HBITMAP

> In reality, the task is a remote rendering, which means just starting some
> application somewhere on the remote computer and getting an image or a bunch
> of them as a result. Any help will be appreciated. Any ideas are wellcome.
> Even crazy ones.

I think there are some opengl remote rendering libraries available

Michael

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