[osg-users] RRT with HDR texture

Benoit bossavit bnuaster at gmail.com
Wed Sep 12 08:21:26 PDT 2007


Ok, seems work better..
what is the diferrence between FragData y FragColor?

thanks you very much Art

bnua

2007/9/12, Art Tevs <stud_info2 at yahoo.de>:
>
> No OpenGl do not clamp float textures, even on using
> luminance. No there do not exists any GL_R16F_ARb or
> GL_RED16F_ARB.
>
> Try to setup your texture with internal parameter
> GL_LUMINANCE16F_ARB and source type as GL_RED. And
> write to the red channel in your shader output.
>
> And yes, try to make something like this in your
> shader:
>
> gl_FragData[0].r = your_result;
>
> and not
>
> gl_FragColor.r = your_result;
>
>
> Art
>
>
> --- Benoit bossavit <bnuaster at gmail.com> schrieb:
>
> > I'm using shaders.
> >
> > I have overloaded the traverse function of a group
> > and I apply my shaders.
> >
> > void Myclass::traverse(osg::NodeVisitor& nv)
> > {
> >     if
> >
> (nv.getVisitorType()==osg::NodeVisitor::CULL_VISITOR)
> >     {
> >         // special actions must be taken if the node
> > visitor is actually a
> > CullVisitor
> >         osgUtil::CullVisitor *cv =
> > dynamic_cast<osgUtil::CullVisitor
> > *>(&nv);
> >
> >         cv->pushStateSet(myStateSet);
> >         osg::Group::traverse(nv); // draws the scene
> >         cv->popStateSet();
> >    }
> > }
> >
> > ss contains my shaders.
> >
> > this class (inherit of group) is the father of the
> > scene, and I attach this
> > class to my camera.
> >
> > But what I don't understand that's work with GL_RGBA
> > and don't work with
> > GL_LUMINANCE.
> > It is possible OpenGL uses a filter when computes
> > the luminance value and
> > clamp it automatically?
> > In this case their is a mean to retrieve only the
> > red component?
> > I don't find GL_R16F_ARG :s
> >
> > thanks for your attention.
> >
> > bnua
> >
> > 2007/9/12, Art Tevs <stud_info2 at yahoo.de>:
> > >
> > > How do you render data into your texture?
> > > If you do not use shaders (so using of fixed
> > function
> > > pipeline) for rendering output to your texture,
> > then
> > > the result will be clamped to [0,1].
> > >
> > > Art
> > >
> > >
> > > --- Benoit bossavit <bnuaster at gmail.com> schrieb:
> > >
> > > > thanks for your answer but I have tried and this
> > is
> > > > don't work :s
> > > > have you other suggestion? I'm surprise that
> > don't
> > > > work !!!
> > > >
> > > > thanks you
> > > >
> > > > bnua
> > > >
> > > > 2007/9/12, Art Tevs <stud_info2 at yahoo.de>:
> > > > >
> > > > > Try to use GL_LUMINANCE16F_ARB (and source
> > format
> > > > > GL_LUMINANCE) instead of GL_INTENSITY16F_ARB.
> > > > >
> > > > > Art
> > > > >
> > > > > --- Benoit bossavit <bnuaster at gmail.com>
> > schrieb:
> > > > >
> > > > > > Hi all,
> > > > > >
> > > > > > I want to do RTT with HDR saving only one
> > > > component
> > > > > > (GL_LUMINANCE or
> > > > > > GL_INTENSITY)
> > > > > > There is my code :
> > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> myHDRTexture->setFilter(osg::Texture::MIN_FILTER,osg::Texture::LINEAR);
> > > > > >
> > > > >
> > > >
> > >
> >
> myHDRTexture->setFilter(osg::Texture::MAG_FILTER,osg::Texture::LINEAR);
> > > > > >
> > > > >
> > > >
> > >
> >
> myHDRTexture->setInternalFormat(GL_INTENSITY16F_ARB);
> > > > > > myHDRTexture->setSourceFormat(GL_INTENSITY);
> > > > > > myHDRTexture->setSourceType(GL_FLOAT);
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > >
> > >
> > >
> >
>
> myCameraHDR->setRenderTargetImplementation(osg::CameraNode::FRAME_BUFFER_OBJECT);
> > > > > >
> > > > >
> > > >
> > >
> >
> myCameraHDR->setRenderOrder(osg::CameraNode::PRE_RENDER);
> > > > > >
> > > > >
> > > >
> > >
> >
> myCameraHDR->attach(osg::CameraNode::COLOR_BUFFER,myRenderHDRTexture);
> > > > > >
> > > > > > when I look values on my texture they are
> > > > clamped at
> > > > > > 1 and if I put :
> > > > > >
> > myHDRTexture->setInternalFormat(GL_RGBA16F_ARB);
> > > > > > myHDRTexture->setSourceFormat(GL_RBA);
> > > > > >
> > > > > > my texture contains values upper than 1
> > > > > >
> > > > > > Someone have an idea? (I don't need saving
> > three
> > > > > > component because they are
> > > > > > the same)
> > > > > >
> > > > > > thanks in advance
> > > > > >
> > > > > > bnua
> > > > > > >
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> >
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> > > > >
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