Hi,
When one float mode did not work then I tried all modes I could see in the gl.h
file. The result on my end was the same every time: 10SPF (seconds per frame)
instead of 30 FPS which I had when testing with GL_RGBA. The first I tried was
GL_LUMINANCE16F_ARB. I figured that I'd start with a simple one (not 32 bit).
My blend function settings are source = ONE, destination = ONE.
The solution I have now where I use 18 bit with 14 overlapping bits in an
unsigned byte RGBA (GL_RGBA mode with additive blend), works, but it would work
much better if I had 32 bits to play with. So, I will have to research this
further in the future. I have to move on now though, the research code done so
far has proven that the technology I am researching works.
Viggo
> Date: Mon, 2 Jun 2008 16:53:24 +0200
> From: [EMAIL PROTECTED]
> To: [email protected]
> Subject: Re: [osg-users] I get errors when trying to render to a
> luminance buffer...
>
> Category: FBO, blending, H/W
>
> Well, I run a different setting from the previous one I mentioned.
> I use osg 1.2 (yeah yeah, I promise to upgrade soon). I haven't integrated
> particle system to my application but I use 1 big billboard with transparency.
> Until now my FBO cameras used GL_RGBA16F_ARB textures, and also the texture
> for the billboard was GL_RGBA16F_ARB.
> I just changed all of them to GL_RGBA32F_ARB and the scene renders correctly.
> (with transparency).
> I haven't tried to save the frames to files and check the precision so I've
> no way to know if the driver didn't fall back to half-float, but I don't
> believe it would do that anyhow. I'd excpect that if there were troubles they
> would be the same as yours. But I get solid frame rate of 80+ Hz.
> (just as before I added the billboard with the blending mode to the scene).
> Again, I work with nVIDIA 8800 GT, driver 6.14.11.6921, on windows XP.
>
> Do you want to send me .osg scenes, or code that I'll test on my machine?
> Maybe you ment GL_LUMINANCE_ALPHA32F_ARB format? If so tell me how to set it
> up instead of the RGBA format and I'll try it.
>
> Guy.
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of J.P. Delport
> Sent: Monday, June 02, 2008 2:22 PM
> To: OpenSceneGraph Users
> Subject: Re: [osg-users] I get errors when trying to render to a luminance
> buffer...
>
> Hi,
>
> (I'm not the guy with the original problem, just interested...)
>
> Guy wrote:
> > Hello,
> >
> >
> >
> > Category: FBO, blending, H/W
> >
> >
> >
> > I don't understand exactly what do you mean but H/W blending with float
> > is not supported.
> >
> > I know for sure that we render particle effect with transparency to
> > float (16bit) FBO, and get the correct results. We also get that with a
> > decent frame rate (100-200Hz depending on the number of particles).
>
> I'm interested in transparency with 32bit floats (alpha blending). Have
> you tested that? I would like to know if it is supported in hardware.
>
> >
> >
> >
> > So I've the feeling that I didn't understand what you mean be blend.
> >
> >
> >
> > Our H/W is nVIDIA 8800 driver 6.14.11.6921 osg2.0 I think J
> >
> >
> >
> > I'd appreciate if you clarify your problem.
> >
> > Thanks,
> >
> > Guy.
>
> jp
>
> >
> >
> >
> > ------------------------------------------------------------------------
> >
> > *From:* [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED] *On Behalf Of *Viggo
> > L?vli
> > *Sent:* Monday, June 02, 2008 11:29 AM
> > *To:* OpenSceneGraph Users
> > *Subject:* Re: [osg-users] I get errors when trying to render to a
> > luminance buffer...
> >
> >
> >
> > Hi again :-)
> >
> > I abandoned the idea of using a floating point buffer.
> > I went into the thinking box and came to the same conclusion as you
> > wrote about in the end of your comment.
> >
> > I needed a quite high resolution so I decided to use all 4 channels
> > (RGBA). The numbers I want to accumulate is seldom large, so I needed
> > most resolution in the lower scale.
> > I thus decided to use RGBA where R is most significant and A is least
> > significant.
> > Bit usage is:
> > R = 6 bits
> > G = 5 bits
> > B = 4 bits
> > A = 3 bits
> > All non used bits will overlap with next channel.
> >
> > I am using this to generate a pixel weight when rendering many
> > volumetric clouds on top of each other on screen. Naturally most
> > overlapping clouds will be further away from camera, so I needed as high
> > a number of overlap bits on the lest significant buffers that I could
> > get. My usage accepts in worst case 32 overlapping pixels with maximum
> > weight (in the distance). I think that is something I can live with :-)
> >
> > Anyhow, I got a range (18 bit) that was good enough for my usage and it
> > gives a decent cloud sorting for clouds seen up to 40 kilometers away.
> >
> > I must stress one point:
> > - If you ever try using the alpha channel for this then remember to turn
> > off alpha-clipping (set alpha-func to always).
> >
> > Viggo
> >
> >
> >> Date: Mon, 2 Jun 2008 10:05:24 +0200
> >> From: [EMAIL PROTECTED]
> >> To: [email protected]
> >> Subject: Re: [osg-users] I get errors when trying to render to a
> > luminance buffer...
> >>
> >> 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: [EMAIL PROTECTED]
> >> > > To: [email protected]
> >> > > 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 <[EMAIL PROTECTED]>
> > 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: [EMAIL PROTECTED]
> >> > > >> To: [email protected]
> >> > > >> 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 <[EMAIL PROTECTED]>
> >> > 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.
> >> > > >> > _______________________________________________
> >> > > >> > osg-users mailing list
> >> > > >> > [email protected]
> >> > > >> >
> >> > > >> >
> >> >
> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> >> > > >> >
> >> > > >> >
> >> > > >> _______________________________________________
> >> > > >> osg-users mailing list
> >> > > >> [email protected]
> >> > > >>
> >> >
> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> >> > > >
> >> > > >
> >> > > > ________________________________
> >> > > > SkyDrive er her. Glem minnepinnen!
> >> > > > _______________________________________________
> >> > > > osg-users mailing list
> >> > > > [email protected]
> >> > > >
> >> >
> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> >> > > >
> >> > > >
> >> > > _______________________________________________
> >> > > osg-users mailing list
> >> > > [email protected]
> >> > >
> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> >> >
> >> > ------------------------------------------------------------------------
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> >> >
> >> >
> >> > ------------------------------------------------------------------------
> >> >
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> >>
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