Thread: [PyOpenGL-Users] offscreen rendering problem with glInitFramebufferObjectEXT
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From: Revaz Y. <yve...@ep...> - 2010-01-21 21:10:38
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Dear List,
I would like to use off-screen rendering with PyOpenGL.
According to the few informations I found on the web, one method is
to use a FrameBufferObject.
Unfortunately, when initializing a new FrameBuffer :
from OpenGL.GL.EXT.framebuffer_object import *
glInitFramebufferObjectEXT()
I get :
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
/home/revaz/<ipython console> in <module>()
/usr/lib/pymodules/python2.6/OpenGL/raw/GL/EXT/framebuffer_object.pyc in
glInitFramebufferObjectEXT()
301
302
303 def
glInitFramebufferObjectEXT():
304 '''Return boolean indicating whether this extension is
available'''
--> 305 return extensions.hasGLExtension( EXTENSION_NAME
)
/usr/lib/pymodules/python2.6/OpenGL/extensions.py in
hasGLExtension(specifier)
32 print
AVAILABLE_GL_EXTENSIONS
33 if not
AVAILABLE_GL_EXTENSIONS:
---> 34 AVAILABLE_GL_EXTENSIONS[:] =
glGetString( GL_EXTENSIONS ).split()
35 return specifier in
AVAILABLE_GL_EXTENSIONS
36
the problem here is that GL_EXTENSIONS is None !
I'm running linux/ubuntu 9.10, python2.6 and PyOpenGL 3.0.1b1
All other suggestions about using off-screen rendering with PyOpenGL
are welcome.
Cheers,
yves
--
(o o)
--------------------------------------------oOO--(_)--OOo-------
Yves Revaz
Laboratory of Astrophysics EPFL
Observatoire de Sauverny Tel : ++ 41 22 379 24 28
51. Ch. des Maillettes Fax : ++ 41 22 379 22 05
1290 Sauverny e-mail : Yve...@ep...
SWITZERLAND Web : http://www.lunix.ch/revaz/
----------------------------------------------------------------
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From: Dan H. <Dan...@no...> - 2010-01-21 21:28:48
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Revaz Yves wrote: > Dear List, > > I would like to use off-screen rendering with PyOpenGL. > According to the few informations I found on the web, one method is > to use a FrameBufferObject. > > Unfortunately, when initializing a new FrameBuffer : > > from OpenGL.GL.EXT.framebuffer_object import * > glInitFramebufferObjectEXT() > > I get : [error snipped] Have you tried initializing PyOpenGL first? When I try running those two lines of code on a machine that I know has the frame buffer object extension, without initial PyOpenGL first, I get the same error message. In general, I would recommend using the frame buffer object extension for off-screen rendering. There are older techniques like p-buffers, but they're more difficult to use. One downside of frame buffer objects is that some older/cheaper graphics chipset drivers do not support them. Dan |
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From: Revaz Y. <yve...@ep...> - 2010-01-21 21:41:18
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Dan Helfman wrote:
> Revaz Yves wrote:
>
>> Dear List,
>>
>> I would like to use off-screen rendering with PyOpenGL.
>> According to the few informations I found on the web, one method is
>> to use a FrameBufferObject.
>>
>> Unfortunately, when initializing a new FrameBuffer :
>>
>> from OpenGL.GL.EXT.framebuffer_object import *
>> glInitFramebufferObjectEXT()
>>
>> I get :
>>
>
> [error snipped]
>
> Have you tried initializing PyOpenGL first?
>
> When I try running those two lines of code on a machine that I know has
> the frame buffer object extension, without initial PyOpenGL first, I get
> the same error message.
>
ok, fine ! now it works, after a
glutInitDisplayMode
which initialize OpenGL.
But how can I initialize OpenGL without creating a window ?
> In general, I would recommend using the frame buffer object extension
> for off-screen rendering.
ok, so I'm on the right way.
Any example will be welcome...
Cheers,
yves
> There are older techniques like p-buffers, but
> they're more difficult to use. One downside of frame buffer objects is
> that some older/cheaper graphics chipset drivers do not support them.
>
> Dan
>
--
(o o)
--------------------------------------------oOO--(_)--OOo-------
Yves Revaz
Laboratory of Astrophysics EPFL
Observatoire de Sauverny Tel : ++ 41 22 379 24 28
51. Ch. des Maillettes Fax : ++ 41 22 379 22 05
1290 Sauverny e-mail : Yve...@ep...
SWITZERLAND Web : http://www.lunix.ch/revaz/
----------------------------------------------------------------
|
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From: Dan H. <Dan...@no...> - 2010-01-21 21:50:38
|
Revaz Yves wrote: > ok, fine ! now it works, after a > > glutInitDisplayMode > > which initialize OpenGL. > But how can I initialize OpenGL without creating a window ? > >> In general, I would recommend using the frame buffer object extension >> for off-screen rendering. > ok, so I'm on the right way. > Any example will be welcome... The only time I've used the FBO extension is when I've got an OpenGL window open, e.g. for rendering a separate pick buffer so I can tell what the user clicks on. I don't know of a way to initialize GL without a window, although it's certainly possible to initialize GL without using GLUT. You can use wxPython's GLCanvas, for instance. But even GLCanvas expects a parent window. Dan |
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From: Revaz Y. <yve...@ep...> - 2010-01-21 21:55:07
|
>
> The only time I've used the FBO extension is when I've got an OpenGL
> window open, e.g. for rendering a separate pick buffer so I can tell
> what the user clicks on. I don't know of a way to initialize GL without
> a window,
ok, maybe it's not so important... however I expected to run backgound
scripts...
> although it's certainly possible to initialize GL without
> using GLUT. You can use wxPython's GLCanvas, for instance. But even
> GLCanvas expects a parent window.
>
sure,
well, anyway, thanks for your precious help.
yves
> Dan
>
--
(o o)
--------------------------------------------oOO--(_)--OOo-------
Yves Revaz
Laboratory of Astrophysics EPFL
Observatoire de Sauverny Tel : ++ 41 22 379 24 28
51. Ch. des Maillettes Fax : ++ 41 22 379 22 05
1290 Sauverny e-mail : Yve...@ep...
SWITZERLAND Web : http://www.lunix.ch/revaz/
----------------------------------------------------------------
|
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From: Dan H. <Dan...@no...> - 2010-01-21 22:21:55
|
Revaz Yves wrote: > >> >> The only time I've used the FBO extension is when I've got an OpenGL >> window open, e.g. for rendering a separate pick buffer so I can tell >> what the user clicks on. I don't know of a way to initialize GL >> without a window, > ok, maybe it's not so important... however I expected to run backgound > scripts... FYI: http://stackoverflow.com/questions/576896/can-you-create-opengl-context-without-opening-a-window Dan |
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From: Revaz Y. <yve...@ep...> - 2010-01-22 01:05:15
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Ok, I've found nice solutions to my problem:
- with glut, to avoid to display a window simply use glutHideWindow :-[ :
glutCreateWindow("my window")
glutHideWindow()
- simple and good examples about offscreen rendering using FrameBuffer
and Renderbuffer can be found here:
http://www.opengl.org/wiki/GL_EXT_framebuffer_object
Cheers,
yves
Dan Helfman wrote:
> Revaz Yves wrote:
>
>>> The only time I've used the FBO extension is when I've got an OpenGL
>>> window open, e.g. for rendering a separate pick buffer so I can tell
>>> what the user clicks on. I don't know of a way to initialize GL
>>> without a window,
>>>
>> ok, maybe it's not so important... however I expected to run backgound
>> scripts...
>>
>
> FYI:
>
> http://stackoverflow.com/questions/576896/can-you-create-opengl-context-without-opening-a-window
>
> Dan
>
--
(o o)
--------------------------------------------oOO--(_)--OOo-------
Yves Revaz
Laboratory of Astrophysics EPFL
Observatoire de Sauverny Tel : ++ 41 22 379 24 28
51. Ch. des Maillettes Fax : ++ 41 22 379 22 05
1290 Sauverny e-mail : Yve...@ep...
SWITZERLAND Web : http://www.lunix.ch/revaz/
----------------------------------------------------------------
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