[osg-users] Searcing for raytracer implementation based on OSG

Adrian Egli 3dhelp at gmail.com
Tue Oct 9 08:34:44 PDT 2007


Hi

just for your informations

i am working on a KD-Tree based line intersection test. First result are
quite better, event for the cow object with 5804 and passed 1000.0 lines
trought the object with 2 real intersection we have just to check against 33
triangles instead of all (5804).



B-Radius=6.35558
B-Center=0.776125,-0.43866,0
KD-Tree...[5804:1001]
5804:5804
TrianglesChecks=5804
Total Bench Time: 0.209096s

C:\Dokumente und Einstellungen\adegli>"C:\Dokumente und
Einstellungen\adegli\Desktop\test\Release\Test.exe"
B-Radius=6.35558
B-Center=0.776125,-0.43866,0
KD-Tree...[5804:1001]
5804:5804
TrianglesChecks=33
Total Bench Time: 0.0879453s

C:\Dokumente und Einstellungen\adegli>

2007/10/3, Adrian Egli <3dhelp at gmail.com>:
>
> Hi
>
> there are many nice project and on going project for real time ray
> tracing. i would say in the future there will be many more, because
> the ray tracing becomes faster and faster. The future will be a hybrid
> visualisation systems: GPU / CPU and also OpenGL / RayTracing.
>
> Even for OSG it will become a challenge to follow such latest development
> and such latest ideas, but the core concept of all such systems are quite
> similar.
> All systems needs a spatial data structure. In OSG the objects are
> organised in bounding sphere hierarchy. And unfortunately the
> primitives are just in arrays, what is may fast for rendering but for
> intersection testing, tracing it's a known poor data organisation.
>
> (Robert) What are you thinking about this topic, just as a short general
> idea. What danger do you see if we would implement a spatial hierarchic data
> structure (kd-tree) to replace the array based vertex, triangles storing.
> what can be a challenge or what would be quite hard to change, and where are
> unknown dangers w.r.t performance for face rendering (OpenGL) ?
>
> /adegli
>
> 2007/10/2, Abe Stephens <abe at sci.utah.edu>:
> >
> >
> > I'm not aware of any open source interactive ray tracers that
> > vivaciously support third-party scene graphs like OSG.
> >
> > OpenRT (not open source) has been demoed at the Mercury booth @
> > siggraph running off a scene graph (possibly OpenInventor (?)). Razor
> > (not open source) is an IRT system from UT Austin which is tightly
> > integrated with its own scene graph (supports collada). We've had
> > some traffic on the Manta (open source) mailing list about scene
> > graph integration. The projects were all outside of Utah so I'm not
> > sure if they targeted a standard tool like OSG.
> >
> > Abe
> >
> >
> > On Oct 2, 2007, at 4:26 AM, osg-users-
> > request at lists.openscenegraph.org wrote:
> >
> > > Message: 24
> > > Date: Tue, 2 Oct 2007 12:25:58 +0200
> > > From: " Tobias M?nch " <muench.tobias at googlemail.com>
> > > Subject: Re: [osg-users] Searcing for raytracer implementation based
> > >       on OSG
> > > To: "OpenSceneGraph Users" <osg-users at lists.openscenegraph.org>
> > > Message-ID:
> > >       < f90040970710020325s44d43a11m799458b0db13458f at mail.gmail.com>
> > > Content-Type: text/plain; charset="iso-8859-1"
> > >
> > > Hello Adrian
> > >
> > > If I get you right, you think that the OSG data representation is not
> > > optimized for use within a raytracer application. So it will be
> > > possible to
> > > code a raytracer with OSG but results won't be very efficient and
> > > powerful?
> > >
> > > regards, Tobias
> > >
> > > On 10/2/07, Adrian Egli <3dhelp at gmail.com> wrote:
> > >>
> > >> Hi Tobias,
> > >>
> > >> Greate would be to get a RayTracer attached to the OSG scene. With
> > >> option
> > >> to trace or not. Normally OSG won't trace, but if we like to get high
> > >> quality screens, we can just turn on the tracing. But i was
> > >> thinking about
> > >> this still more then once. What we should get or what i like to
> > >> integrate as
> > >> soon as i have some hours to analyse the osg core, we should store
> > >> the
> > >> triangles, trianglesfan, ... (GL geometries) in a accelerated
> > >> spatial data
> > >> structure, best kd-Tree like data organisation. Even the
> > >> intersection test
> > >> could be boosted, also futures animations, collision checks and so
> > >> on,
> > >> boosting of depth sorting for transparency pre triangles should
> > >> become
> > >> possible.  Also haptic-rendering could be an option for future
> > >> application.
> > >> This integration would be an essential topic.
> > >>
> > >> I am not yet sure how we should change the osg internal data
> > >> structure, at
> > >> the moment we store vertices in simple arrays. I feel like to
> > >> remap them
> > >> into an kd-tree. then the whole scenegraph is organised in a
> > >> spatial data
> > >> structure.
> > >>
> > >> and the once we have a fast internal data representation, we may are
> > >> really close to render the scene no longer as face rendering also ray
> > >> casted, ray traced parts would be an futur options. what would be
> > >> really
> > >> greate. May we will get small parts raytraced, others not.
> > >>
> > >> what are others thinking about this topic.
> > >>
> > >> /Adegli
> > >>
> > >> 2007/10/2, Tobias M?nch < muench.tobias at googlemail.com>:
> > >>>
> > >>> Hello to all OSG developers.
> > >>>
> > >>> Does anybody has developed a raytracer based on OSG or OpenGL
> > >>> which is
> > >>> free to use on other applications? It is important for me that no
> > >>> changes
> > >>> are necessary to the OSG-framework like the raytracer of Amit Ben-
> > >>> David, who
> > >>> modified the osg:Vec3f class. I need it for my thesis and
> > >>> unfortunately I
> > >>> have not enough time to code one by my own.
> > >>>
> > >>> best regards, Tobias
> > >>>
> > >>> p.s.: The source of Ben-Davids raytracer: http://
> > >>> www.cs.technion.ac.il/~cs234326/projects/GLSLRayTracer/main.htm
> > <http://www.cs.technion.ac.il/%7Ecs234326/projects/GLSLRayTracer/main.htm>
> > >>>
> > >>> <http://www.cs.technion.ac.il/%7Ecs234326/projects/GLSLRayTracer/
> > >>> main.htm>
> > >>>
> > >>> _______________________________________________
> > >>> osg-users mailing list
> > >>> osg-users at lists.openscenegraph.org
> > >>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-
> > >>> openscenegraph.org
> > >>>
> > >>>
> > >>>
> > >>
> > >>
> > >> --
> > >> ********************************************
> > >> Adrian Egli
> > >> _______________________________________________
> > >> osg-users mailing list
> > >> osg-users at lists.openscenegraph.org
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> --
> ********************************************
> Adrian Egli




-- 
********************************************
Adrian Egli
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