[osg-users] I get errors when trying to render to a luminance buffer...
J.P. Delport
jpdelport at csir.co.za
Mon Jun 2 01:05:24 PDT 2008
Hi,
Viggo Løvli wrote:
> Ok, that make sense.
> It happens every time I render with a floating point texture.
>
> The fall in framerate does not happen when I run the OSG multi render
> target example using HDR. My code does however use additive blending
> toward the floating point texture so I bet that is what cause it to fall
> into a software rendering mode.
We have also experienced this slowdown when blending was enabled with
float textures. Testing on newer cards is pending as we cannot figure
out from docs on the internet if this is actually supported in current
hardware at all. Seems like DX10.1 mandates float blending, but we will
test to make sure. Please let me know if you know if it is supported in
hardware.
>
> Do you know about any texture surface bit format that is more than 8
> bits (unsigned integer) ?
I don't know of any. I've only seen a paper once where people were using
three channels to simulate one large channel. The RGB channels were
partially overlapped to create a higher dynamic range channel.
jp
>
> Viggo
>
>
> > Date: Fri, 30 May 2008 16:29:05 +0100
> > From: robert.osfield at gmail.com
> > To: osg-users at lists.openscenegraph.org
> > Subject: Re: [osg-users] I get errors when trying to render to a
> luminance buffer...
> >
> > Hi Viggo,
> >
> > When performance drops like this it's because you've dropped onto a
> > software fallback path in the OpenGL driver. Exactly what formats are
> > software vs hardware depends upon the hardware and OpenGL drivers.
> > You'll need to check with your hardware vendors specs to see what will
> > be hardware accelerated.
> >
> > Robert.
> >
> > On Fri, May 30, 2008 at 2:16 PM, Viggo Løvli <vigigio at hotmail.com> wrote:
> > > Hi Robert,
> > >
> > > I modified my code as you suggested.
> > > The warning is gone :-)
> > >
> > > The framerate is now 10 seconds per frame instead of 30 frames per
> second.
> > > It does something.
> > > The texture I render to remains black (cleared to black).
> > >
> > > If I change the setInternalFormat to GL_RGBA then the framerate is
> up again,
> > > and the texture gets colors. This works, but then I only have 8 bit
> in the
> > > red channel. What I need is as many bits as possible in the red
> channel,
> > > preferably 32. And I do not need GBA channels.
> > > Do you have a suggestion for me on this one?
> > >
> > > Viggo
> > >
> > >> Date: Fri, 30 May 2008 13:25:24 +0100
> > >> From: robert.osfield at gmail.com
> > >> To: osg-users at lists.openscenegraph.org
> > >> Subject: Re: [osg-users] I get errors when trying to render to a
> luminance
> > >> buffer...
> > >>
> > >> Hi Viggo,
> > >>
> > >> The warning is exactly right, pbuffers don't suport multiple render
> > >> targets, only FrameBufferObjects do.
> > >>
> > >> Perhaps what you intend it not to use multiple render targets, in
> > >> which case you should set the Camera attachment to COLOR_BUFFER rather
> > >> than COLOR_BUFFER0, that later tells the OSG that you want MRT and
> > >> will be using glFragColor[] in your shaders.
> > >>
> > >> Also the Camera::setDrawBuffer(GL_COLOR_ATTACHMENT0_EXT) is
> > >> inappropriate for pbuffers.
> > >>
> > >> Robert.
> > >>
> > >> On Fri, May 30, 2008 at 1:18 PM, Viggo Løvli <vigigio at hotmail.com>
> wrote:
> > >> > Hi,
> > >> >
> > >> > I want to render to a floating point buffer, and I set things up
> like
> > >> > this:
> > >> >
> > >> > tex->setInternalFormat( GL_LUMINANCE16F_ARB );
> > >> > tex->setSourceFormat( GL_RED );
> > >> > tex->setSourceType( GL_FLOAT );
> > >> >
> > >> > camera->setRenderTargetImplementation(
> osg::Camera::FRAME_BUFFER_OBJECT
> > >> > );
> > >> > camera->attach( osg::Camera::BufferComponent(
> osg::Camera::COLOR_BUFFER0
> > >> > ),
> > >> > tex );
> > >> > camera->setDrawBuffer( GL_COLOR_ATTACHMENT0_EXT );
> > >> >
> > >> > My fragment-shader that write to the surface output the value
> this way:
> > >> > gl_FragData[0].r = 1.0;
> > >> >
> > >> > Another fragment-shader reads the surface this way:
> > >> > value = texture2DRect( id, gl_FragCoord.xy ).r;
> > >> >
> > >> > I get the following output when I try to run my app:
> > >> > "Warning: RenderStage::runCameraSetUp(state&) Pbuffer does not
> support
> > >> > multiple color outputs."
> > >> >
> > >> > My app runs, but nothing is written to the texture.
> > >> >
> > >> > Is it possible to set up a surface that holds one channel
> (GL_RED) which
> > >> > is
> > >> > an unsigned int of 32 bit resolution? I'd rather use that than a
> float
> > >> > :-)
> > >> >
> > >> > Viggo
> > >> >
> > >> > ________________________________
> > >> > Få Hotmail du også. Windows Live Hotmail nå med 5000 MB gratis
> > >> > lagringsplass.
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> > >> >
> > >> >
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