[osg-users] Saving and restoring GL state with OpenSceneGraph
Preet
I'm trying to find out a bit more about how to get OpenSceneGraph to
share an OpenGL context with another library... and to do that
properly i'd like to isolate both by saving and restoring state as
appropriate. I know this isn't the 'right' way to use OSG, and I know
that this kills performance, especially since OSG is designed to use
lazy state updating... but sometimes its a necessary evil. I'm
targeting OpenGL ES2.
Looking through some other posts, I've gathered:
You can get/save the current stateset by calling something like:
myViewer->getCamera()->getGraphicsContext()->getState()->captureCurrentState(myStateSet);
You can reset the current state by calling reset:
myViewer->getCamera()->getGraphicsContext()->getState()->reset();
You can apply a saved state by calling apply:
myViewer->getCamera()->getGraphicsContext()->getState()->apply(myStateSet);
But I'm not sure about a few things:
When should the osg::State be first saved? So basically, when is the
scene graph first traversed and the osg::State built up so that it's
appropriate for OSG to go ahead and render something? Does the initial
OpenGL state when OSG first builds up osg::State matter (I'm guessing
no)?
After saving this valid state, i'd do something like this to restore
it and render my scene...
// draw call
myViewer->getCamera()->getGraphicsContext()->getState()->reset(); //
is this line necessary?
myViewer->getCamera()->getGraphicsContext()->getState()->apply(myStateSet);
myViewer->frame();
// save state again if I modified the scene
Does that seem reasonable? Any advice/input would be appreciated.
Thanks
Preet
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Frank Kane
But, you could flip the problem on its head and capture the actual OpenGL state just prior to calling your library, and then restoring it when your library is done with its drawing. Here is some code to start from that catches most of the stuff that's likely to change; for completeness, you'd want to capture all of the state documented at http://www.khronos.org/opengles/sdk/1.1/docs/man/glGet.xml as well.
Code:
typedef struct glState_S {
GLboolean depthTest, blend, cullFace;
GLboolean dither, colorLogicOp, polygonOffsetLine, polygonOffsetFill;
GLboolean polygonOffsetPoint, polygonSmooth, scissorTest, stencilTest;
} glState;
static std::stack<glState> stateStack;
SILVERLININGDLL_API bool PushAllState(void)
{
glState state;
state.blend = glIsEnabled(GL_BLEND);
state.depthTest = glIsEnabled(GL_DEPTH_TEST);
state.cullFace = glIsEnabled(GL_CULL_FACE);
state.dither = glIsEnabled(GL_DITHER);
state.polygonOffsetFill = glIsEnabled(GL_POLYGON_OFFSET_FILL);
state.scissorTest = glIsEnabled(GL_SCISSOR_TEST);
state.stencilTest = glIsEnabled(GL_STENCIL_TEST);
stateStack.push(state);
CheckError(__LINE__);
return true;
}
SILVERLININGDLL_API bool PopAllState(void)
{
if (!stateStack.empty()) {
glState state = stateStack.top();
if (state.blend) glEnable(GL_BLEND); else glDisable(GL_BLEND);
if (state.depthTest) glEnable(GL_DEPTH_TEST); else glDisable(GL_DEPTH_TEST);
if (state.cullFace) glEnable(GL_CULL_FACE); else glDisable(GL_CULL_FACE);
if (state.dither) glEnable(GL_DITHER); else glDisable(GL_DITHER);
if (state.polygonOffsetFill) glEnable(GL_POLYGON_OFFSET_FILL); else glDisable(GL_POLYGON_OFFSET_FILL);
if (state.scissorTest) glEnable(GL_SCISSOR_TEST); else glDisable(GL_SCISSOR_TEST);
if (state.stencilTest) glEnable(GL_STENCIL_TEST); else glDisable(GL_STENCIL_TEST);
stateStack.pop();
}
CheckError(__LINE__);
return true;
}
Best regards,
Frank Kane
Founder, Sundog Software LLC
------------------
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John Richardson
The OpenScenegraph Siggraph 2012 BOF will be held in the Los Angeles
Convention Center on 8 August 2012 at 10AM.
This is the second Call for Presentations [32 days until the BOF]
Highlight your work.
Show off your institution.
Hawk your consulting skills.
As long as it is OSG related. Step up now and be virtual.
Notes: Robert will get a default 10-15 minute slot to give a state of OSG
report or whatever he wants to give and presented by whoever he designates.
That leaves 3 15 minutes slots [more if we get enough presenters but no slot <
10 minutes]. First come first allocated. More time if less presenters.
John F. Richardson
Preet
Thanks for the reply! I'll try setting up something similar in my application.
Alejandro Aguilar Sierra
I will present work about plate tectonics simulation.
See you there!
-- A.
John Richardson
There is ONE 15 minute slot left. The DEADLINE is 27 July 2012 to claim the
slot. After that I will give the other presenters 5 more minutes or plan a
panel at the end. I need to plan the final agenda.
The OpenScenegraph Siggraph 2012 BOF will be held in the Los Angeles
Convention Center on 8 August 2012 at 10AM.
Show off your institution.
Hawk your consulting skills.
As long as it is OSG related. Step up now and be virtual.
David Glenn
Gee, I wish I could help you, but I haven't done any OSG stuff that I'm alowed to show off this year, but I will be there to see all the fun!
------------------------
David Glenn
---------------
D Glenn 3D Computer Graphics & Media Systems.
www.dglenn.com
------------------
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Alejandro Aguilar Sierra
I'd like to present a work I have been preparing with one of my
undergrads. It is about a simulation of the plate tectonics evolution
over the sphere during the geologic eras. Of course it is all over
OSG.
Is there still a spot in the agenda?
Thanks in advance.
--
Alejandro Sierra
National University of Mexico
Art Tevs
finally I am also coming to this year's Siggraph, yeah :)
Unfortunately I have nothing to present, since last years I didn't worked with OSG much and hence almost no development in osgPPU.
However, how about a small announcement that we are looking for forum moderators and admins at the BOF? At least I will certainly join the BOF.
Cheers,
Art
------------------
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John Richardson
Will add the announcement to the Into. If you have preferred text for the
announcement, please send to me.
John F. Richardson
John Richardson
You asked for a slot on 17 July and so you already had a slot reserved.
You, Robert's state of OSG slides and Tassilo Glander have the 3 currently
confirmed 15 minute slots.
Could you send me a title slide with any abstract or logos or intro type
text for my agenda slides.
One still up for grabs.....:)
John F. Richardson
-----Original Message-----
From: osg-user...@lists.openscenegraph.org
[mailto:osg-user...@lists.openscenegraph.org] On Behalf Of Alejandro
Aguilar Sierra
Sent: Monday, July 23, 2012 4:57 PM
To: OpenSceneGraph Users
Subject: Re: [osg-users] OpenScenegraph Siggraph 2012 BOF Final Call for
Presentations
David Glenn
>
> > Greetings and Salutations,
> >
> >
> >
> > There is ONE 15 minute slot left. The DEADLINE is 27 July 2012 to claim
> >
> the
>
> > slot. After that I will give the other presenters 5 more minutes or plan a
> > panel at the end. I need to plan the final agenda.
> >
> >
> >
> > The OpenScenegraph Siggraph 2012 BOF will be held in the Los Angeles
> > Convention Center on 8 August 2012 at 10AM.
> >
> > Highlight your work.
> > Show off your institution.
> > Hawk your consulting skills.
> >
> > As long as it is OSG related. Step up now and be virtual.
> >
> >
> > John F. Richardson
> >
> > _______________________________________________
> > osg-users mailing list
> >
> >
> >
> _______________________________________________
> osg-users mailing list
>
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>
> _______________________________________________
> osg-users mailing list
>
>
> ------------------
> Post generated by Mail2Forum
Just thinking up ideas to fill that time.
Did you docket enough time to introduce OSG to Newbes? What it is, what it can do, what it's not and what can fill that role?
What to do you need to install it: In windows, In Linux or In Mac?
Maybe you want to fill in people on add on products Delta 3D that uses OSG?
or Virtual Planet Builder or osgEarth or the progress OSG on embedded systems.
D Glenn
------------------------
David Glenn
---------------
D Glenn 3D Computer Graphics & Media Systems.
www.dglenn.com
Read this topic online here:
John Richardson
If nobody claims the last slot the panel will discuss all this.
Last year Jean-Sébastien Guay gave a complete how to compile and build OSG
tutorial. That did take some time. Well worth it but time consuming.
-----Original Message-----
[mailto:osg-user...@lists.openscenegraph.org] On Behalf Of David Glenn
Sent: Thursday, July 26, 2012 10:14 AM
To: osg-...@lists.openscenegraph.org
John Richardson
Did you send me a title slide or informational slide? I would appreciate it
for the list of presenters list. Can you also send a short abstract so I can
say nice comments about your talk to the audience.
John F. Richardson
-----Original Message-----
From: osg-user...@lists.openscenegraph.org
[mailto:osg-user...@lists.openscenegraph.org] On Behalf Of Alejandro
Aguilar Sierra
Sent: Monday, July 23, 2012 4:57 PM
To: OpenSceneGraph Users
Subject: Re: [osg-users] OpenScenegraph Siggraph 2012 BOF Final Call for
Presentations
Eric Sokolowsky
I am also interested in consulting opportunities for OSG particularly, but also graphics and computer programming in general. At one time I was quite active on the OSG mailing lists and have contributed many enhancements and fixes, and want to get back into this arena once more.
Eric
Torben Dannhauer
I would have some intersting topics to talk about, unfortunately I cannot join the siggraph this year (again..).
Nevertheless, for next year I plan to visit SIGGRAPH the first time.
I hope the new OSG geometrical distortion framework will be finished and submitted, also the CiGi interface should be in a presentable form..
Enjoy the SIGGRAPH!
Cheers,
Torben
------------------
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David Glenn
It was very informative and well done!
D Glenn
John Richardson wrote:
> Hello David,
>
> If nobody claims the last slot the panel will discuss all this.
>
> Last year Jean-Sébastien Guay gave a complete how to compile and build OSG
> tutorial. That did take some time. Well worth it but time consuming.
> John F. Richardson
>
> -----Original Message-----
> From:
> [mailto:] On Behalf Of David Glenn
> Sent: Thursday, July 26, 2012 10:14 AM
> To:
> Subject: Re: OpenScenegraph Siggraph 2012 BOF Final Call for
> Presentations
>
>
> John Richardson wrote:
>
> > Hello Alejandro,
> >
> > You asked for a slot on 17 July and so you already had a slot reserved.
> >
> > You, Robert's state of OSG slides and Tassilo Glander have the 3 currently
> > confirmed 15 minute slots.
> >
> > Could you send me a title slide with any abstract or logos or intro type
> > text for my agenda slides.
> >
> > One still up for grabs.....:)
> >
> > John F. Richardson
> >
> > -----Original Message-----
> > From:
> > [mailto:] On Behalf Of Alejandro
> > Aguilar Sierra
> > Sent: Monday, July 23, 2012 4:57 PM
> > To: OpenSceneGraph Users
> > Subject: Re: OpenScenegraph Siggraph 2012 BOF Final Call for
> > Presentations
> >
> > Hello John,
> >
> > I'd like to present a work I have been preparing with one of my
> > undergrads. It is about a simulation of the plate tectonics evolution
> > over the sphere during the geologic eras. Of course it is all over
> > OSG.
> >
> > Is there still a spot in the agenda?
> >
> > Thanks in advance.
> >
> > --
> > Alejandro Sierra
> > National University of Mexico
> >
> >
> > On Mon, Jul 23, 2012 at 1:22 PM, John Richardson
> > <> wrote:
> >
> >
> > > Greetings and Salutations,
> > >
> > >
> > >
> > > There is ONE 15 minute slot left. The DEADLINE is 27 July 2012 to claim
> > >
> > >
> > the
> >
> >
> > > slot. After that I will give the other presenters 5 more minutes or plan
> > >
> >
> a
>
> >
> > > panel at the end. I need to plan the final agenda.
> > >
> > >
> > >
> > > The OpenScenegraph Siggraph 2012 BOF will be held in the Los Angeles
> > > Convention Center on 8 August 2012 at 10AM.
> > >
> > > Highlight your work.
> > > Show off your institution.
> > > Hawk your consulting skills.
> > >
> > > As long as it is OSG related. Step up now and be virtual.
> > >
> > >
> > > John F. Richardson
> > >
> > > _______________________________________________
> > > osg-users mailing list
> > >
> > >
> > >
> >
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>
> > _______________________________________________
> > osg-users mailing list
> >
> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> >
> > _______________________________________________
> > osg-users mailing list
> >
> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> >
> > ------------------
> > Post generated by Mail2Forum
> >
>
>
> Just thinking up ideas to fill that time.
>
> Did you docket enough time to introduce OSG to Newbes? What it is, what it
> can do, what it's not and what can fill that role?
> What to do you need to install it: In windows, In Linux or In Mac?
>
> Maybe you want to fill in people on add on products Delta 3D that uses OSG?
> or Virtual Planet Builder or osgEarth or the progress OSG on embedded
> systems.
>
> D Glenn
>
> ------------------------
> David Glenn
> ---------------
> D Glenn 3D Computer Graphics & Media Systems.
> www.dglenn.com
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=49079#49079
>
>
>
>
>
> _______________________________________________
> osg-users mailing list
>
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>
> _______________________________________________
> osg-users mailing list
>
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>
> ------------------
> Post generated by Mail2Forum
------------------------
David Glenn
---------------
D Glenn 3D Computer Graphics & Media Systems.
www.dglenn.com
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=49095#49095
Art Tevs
John Richardson wrote:
> Hello Art,
>
> Will add the announcement to the Into. If you have preferred text for the
> announcement, please send to me.
>
> John F. Richardson
>
cheers,
art
------------------
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David Glenn
Had a good time at the BOF, look forward to next year.
Thank you!
------------------------
David Glenn
---------------
D Glenn 3D Computer Graphics & Media Systems.
www.dglenn.com
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