Hello. 1x1 texture should be rendered and call the shaders. I did it once in multipass program that ran some algorithm on the GPU. Be sure that you use orthographic projection and the viewport to be 1x1:
camera->setProjectionMatrixAsOrtho2D(0,1,0,1); camera->setViewport(0, 0, 1, 1); Guy. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of J.P. Delport Sent: Tuesday, April 08, 2008 3:11 PM To: OpenSceneGraph Users Subject: Re: [osg-users] HDR with osg Hi, Roman Grigoriev wrote: > Hi guys! > > I try to implement HDR. And I got some problem when I compute average > luminance > > I have to render it to 1X1 texture and here is the main problem > > When I setup viewport with setVewport(0,0,1,1) - I've got clearcolor > i.e. (1,0,0,0) Is this for a 1x1 target, or for your 2x2 target? I guess your shader is not executed at all. What are you doing in the vertex shader? I have not tried 1x1 textures myself. > > When I setup viewport with setVewport(0,0,2,2) - I've got average > luminance - but here I've got 2X2 texture but I need 1X1 texture At some texture size (search gpgpu.org or experiment) it becomes faster to copy the texture to CPU and do final calculation there. > > What should I do? Debug more :) See if your shader is executed for 1x1 case at all. Turn on more OSG (see OSG_NOTIFY_LEVEL) messages to see if there are not other problems, e.g. non-power of two texture resampling. Try texture rectangles... jp > > Here is my source (luminance2 texture has size of 4X4) > > osg::ref_ptr<osg::Texture2D> finalluminance = new osg::Texture2D; > > finalluminance->setTextureSize( 2, 2); > > > > finalluminance->setInternalFormat(GL_RGBA16F_ARB); > > finalluminance->setSourceFormat(GL_RGBA); > > finalluminance->setSourceType(GL_FLOAT); > > > > > finalluminance->setFilter(osg::Texture2D::MIN_FILTER,osg::Texture2D::LIN EAR); > > > finalluminance->setFilter(osg::Texture2D::MAG_FILTER,osg::Texture2D::LIN EAR); > > finalluminance->setWrap(osg::Texture::WRAP_S, > osg::Texture::CLAMP); > > finalluminance->setWrap(osg::Texture::WRAP_T, > osg::Texture::CLAMP); > > > > osg::ref_ptr<osg::Camera> luminance3Camera = new osg::Camera; > > osg::ref_ptr<osg::Geode> geode = new osg::Geode; > > osg::ref_ptr<osg::Geometry> geom > =osg::createTexturedQuadGeometry(osg::Vec3(0,0,-1),osg::Vec3(1.0,0.0,-1. 0),osg::Vec3(0.0,1.0,-1.0)); > > > geom->getOrCreateStateSet()->setMode(GL_LIGHTING,osg::StateAttribute::OF F); > > geode->addDrawable(geom.get()); > > luminance3Camera->setName("luminance3"); > > > luminance3Camera->setClearColor(osg::Vec4f(1.0f,0.0f,0.0f,1.0f)); > > > luminance3Camera->setProjectionMatrix(osg::Matrix::ortho2D(0,1,0,1)); > > > luminance3Camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF); > > luminance3Camera->setViewMatrix(osg::Matrix::identity()); > > luminance3Camera->setViewport(0,0,2,2); > > > luminance3Camera->setRenderOrder(osg::Camera::POST_RENDER,13); > > > luminance3Camera->setRenderTargetImplementation(osg::Camera::FRAME_BUFFE R_OBJECT); > > > luminance3Camera->attach(osg::Camera::COLOR_BUFFER,finalluminance.get()) ; > > luminance3Camera->addChild(geode.get()); > > > > osg::ref_ptr<osg::StateSet> luminance3stateset > =luminance3Camera->getOrCreateStateSet(); > > > luminance3stateset->setTextureAttributeAndModes(0,luminance2.get(),osg:: StateAttribute::ON); > > luminance3stateset->setAttribute(clamp, > osg::StateAttribute::ON); > > > > root->addChild(luminance3Camera.get()); > > osg::Program* luminance3prg = new osg::Program; > > luminance3stateset->setAttribute(luminance3prg); > > > luminance3prg->addShader(osg::Shader::readShaderFile(osg::Shader::VERTEX , > osgDB::findDataFile("Shaders/downLumExp_vp.glsl"))); > > > luminance3prg->addShader(osg::Shader::readShaderFile(osg::Shader::FRAGME NT, > osgDB::findDataFile("Shaders/downLumExp.glsl"))); > > osg::Uniform* DownSampler = new > osg::Uniform("DownSampler",0); > > luminance3stateset->addUniform(DownSampler); > > > > here is downLumExp.glsl > > > > /*FRAGMENT_SHADER*/ > > uniform sampler2D DownSampler; > > const vec2 samples[16]={ > > -0.375, -0.375, -0.125, -0.375, 0.125, -0.375, 0.375, -0.375, -0.375, > -0.125, -0.125, -0.125, 0.125, -0.125, 0.375, -0.125, -0.375, 0.125, > -0.125, 0.125, 0.125, 0.125, 0.375, 0.125, -0.375, 0.375, -0.125, 0.375, > 0.125, 0.375, 0.375, 0.375 > > }; > > > > void main(void) > > { > > float lum = 0.0; > > float maximum = 0.0; > > vec4 color; > > vec2 sample; > > for(int i = 0; i < 16; i++) > > { > > sample = vec2(samples[i].x,samples[i].y); > > color = texture2D(DownSampler, gl_TexCoord[0].xy + > sample); > > maximum = max( maximum, color.g ); > > lum += color.r; > > } > > > > lum *= 0.0625; > > lum = exp(lum); > > gl_FragColor = vec4(lum, maximum, 0.0, 1.0); > > } > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.or g -- This message is subject to the CSIR's copyright terms and conditions, e-mail legal notice, and implemented Open Document Format (ODF) standard. 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