Re: [osg-users] Parallel-Split Shadow Map with osg [PSSM]

Wed, 20 Sep 2006 10:48:10 -0700

hi,

may we can share the code and continue developing a such a "general" shadowing node.

i am happy to get help from you. :-) let's start doing things nice.

adegli

2006/9/20, Radu Mihai <[EMAIL PROTECTED]>:
Hi Adrian,

Thanks for the info, I have a whole afternoon worth of reading with PSSM.

One thing to mention, in your code, you render into the color buffer for the shadowMaps
camera->attach(osg::CameraNode::COLOR_BUFFER, texture);
versus
// attach the texture and use it as the depth buffer.
    shadowCamera->attach(osg::CameraNode::DEPTH_BUFFER, tex);
and use this internal format for the textures
tex->setInternalFormat(GL_DEPTH_COMPONENT);

On the application stage, there is a fragment shader that does shadow comparisons when sampling the SM.
You'll find the code in the osgdepthshadow.cpp example.

I just spent some time refactoring that to create a class for depth shadowing, and I'm quite interested in creating a NodeKit out of it, I'm just not sure how to go about it and what are the requirements of a NodeKit.

Here's how I think this could be handled:
- SSM NodeKit - standard shadow map, using FBO and GL_DEPTH textures 
there's an point of interest being discussed  in the list about doing a depth-only FBO render
after the FBO version is running well, there can be some fall-back methods added
- derive a PSSM NodeKit based on the previous one
I think the approach here would be to have MultiTexturing used in the SSM kit and use that capability in the PSSM kit to do the texture management
additionally there will be code to manage the creation of the splits

This kind of approach would allow me to combine job-related work with OSG contributions :)

If you're interested, and if you think this is a good way to proceed, I'll post the code I have and we can go forward from there.

--------------------------
Radu Mihai

On 20-Sep-06, at 2:47 AM, Adrian Egli wrote:

hi

i like to implement a PSSM nodekit, it has to be as general and robust as possible and should be easy to use. And it should support GLSL shader's (if the system support them) and should work on all platform as well under older system configurations.

the first piece of code i posted is just in an early starting stage. you can compare the result with the gamedev's demo implementation using directX. ( http://www.openscenegraph.org/osgwiki/pmwiki.php/NodeKits/NodeKits
// Parallel-Split Shadow Maps : I started with the openscenegraph integration, i would be very pleased if the community would support me. more information about PSSM, have a look at GameDev, to get involed please contact Adrian Egli [3dhelp (@) gmail.com])

the shadow maps aren't yet right, i guess there is still a bug inside the calculation, i need help in debugging, architectural discusion and so on.

/regards
adegli

2006/9/19, Mihai Radu <[EMAIL PROTECTED]>:
Hi Adrian,

I'm currently working on depthShadow code, but not (yet :) partitioned, so I'm
dealing with similar issues.
I took a quick look @ the code you posted, and seems to be working ok.

What kind of help did you have in mind ?

--
Mihai Radu
cm-labs.com

On Monday 18 September 2006 10:48, Robert Osfield wrote:
> Hi Adrian,
>
> I don't have time to dabble right now, but pehaps others do.  Could you
> provide a link to further information on the algorithm you are using, also
> set up a page for this work on the community section of the wiki under the
> NodeKit seftion, this way you can update the source and screenshots etc
> without needing to send everything into the list.
>
> Cheers,
> Robert.
>
> On 9/18/06, Adrian Egli < [EMAIL PROTECTED]> wrote:
> > hi i am currently implementing PSSM shadowing technic for osg. who likes
> > to help me.
> >
> > try out the latest state of the implementation.
> >
> > /adegli
> > _______________________________________________
> > osg-users mailing list
> > [email protected]
> > http://openscenegraph.net/mailman/listinfo/osg-users
> > http://www.openscenegraph.org/
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