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). 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 :-) I'd appreciate if you clarify your problem. Thanks, Guy. ________________________________ 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 > > > > ------------------------------------------------------------------------ > > SkyDrive er her. 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