Ok thank you for the advice. I'm not very familiar with the shader programming yet, but I'm suppose to get into it soon. The problem that I see is how to get access to the facet from the shader. If I'm into a fragment shader I'll probably have no idea from which facet come each fragment. Is it right? Maybe I have to use a geometry shader? Or maybe I can perform the blending by myself into a fragment shader? You can tell me if you have any clue about that.
I'll give you a little more of precision about my problem. The blending seems to be working when the alpha of the front facet is different from 1. For exemple if I define Rd = (2e-3, 0.0, 0.0, 1.0) // RGBA Rs = (6e-9, 0.0, 0.0, 0.4) //RGBA In theory: Rd = Rs + (1-As)Rd Rd = 6e-9 + (1-0.4)*2e-3 = 1.200006e-3 In practice I get: 0.0012000059 For now, the problem seems to occur only when As =1. Thanks, Jonathan 2009/5/26 J.P. Delport <[email protected]> > Hi, > > Jonathan Richard wrote: > > > > |// Tell to sort the mesh before displaying it > > |AFAIK OSG does not sort at the triangle level, there is an option to > > make the sorting happen at a primitive level, but I think the default is > > sorting on bounding sphere. > > > > I take this line (and the comment) from the osgblendequation example. > > You think that I should not do this call? > > No, the call is fine. What I'm saying is that blending and transparency > is (depending on the blend equation) dependent on the order in which > things are rendered, so one cannot assume (when making off-line > calculations) that all the geometry is perfectly sorted (think e.g. > intersecting objects). > > > > > |offscreenTexture->setSourceType( GL_UNSIGNED_BYTE); > > |Should this not also be GL_FLOAT? > > > > yes sorry it is a "copy paste" error. I call > > offscreenTexture->setSourceType(GL_FLOAT) and > > offscreenTexture->setInternalFormat(GL_FLOAT_RGBA32_NV). > > > > |I can also not see from the code if OpenGL lighting is enabled. Do you > > disable lighting in your app? > > > > No I wasn't but I disable it now and I see no change in the result > > OK. > > I'm running out of ideas to try help. I cannot from just reading the > code see any more problems. I'd suggest using the ARB modes and trying a > few other machines. I'll also try find some of our test code for float > blending. > > Another option is to use shaders to explicitly set the colours of two > facets (to eliminate any fixed function interference) and see how they > blend. > > jp > > > > > > > > Here a update of the code with the correction in yellow: > > > > > > The colors are attached by setting the ColorArray of the drawables of > > each Geode like this: > > > > > > > > int geodesNb = m_entityVectorOfGeodeVector[0].size(); > > > > > > > > osg::Geode* aGeode; > > > > int drawablesNb; > > > > osg::Drawable* aDrawable; > > > > osg::Geometry* aDrawableGeometry; > > > > osg::Vec4Array* aDrawableColor; > > > > for (int geodesLoop = 0; geodesLoop < geodesNb; geodesLoop++) > > > > { > > > > aGeode = m_entityVectorOfGeodeVector[0][geodesLoop]; > > > > drawablesNb = aGeode->getNumDrawables(); > > > > > > > > // Update color for each facet (drawable) of a geode > > > > for (int i = 0; i < drawablesNb; i++) > > > > { > > > > aDrawable = aGeode->getDrawable(i); > > > > aDrawable->dirtyDisplayList(); // > > Force color update on next draw > > > > > > > > aDrawableGeometry = > > dynamic_cast<osg::Geometry*>(aDrawable); > > > > > > > > aDrawableColor = > > dynamic_cast<osg::Vec4Array*>(aDrawableGeometry>getColorArray()); > > > > > > > > > > std::string geodeName=aGeode->getName(); > > > > > > > > if(!geodeName.compare("p1")) > > > > { > > > > // Set the facet color > > and transparency (0=invisible) > > > > (*aDrawableColor)[0] = > > m_facet1Color; > > > > > > > > … > > > > } > > > > } > > > > } > > > > > > > > Where the /entityVectorOfGeodeVector/ is the list of visible geodes that > > I maintain by using a cull callback. > > > > > > > > > > > > Here a snapshot of my code to setup the viewer and the camera. > > > > > > > > m_viewer = new osgViewer::Viewer; > > > > m_viewer->setUpViewOnSingleScreen(); > > > > osg::Camera *camera = m_viewer->getCamera(); > > > > > > > > osgViewer::Renderer * renderer = > > static_cast<osgViewer::Renderer*>(camera->getRenderer()); > > > > // Reading back the FBO does not work when it is disabled after render > > --> set this property of the > > > > // renderStage to false. > > > > > renderer->getSceneView(0)->getRenderStage()->setDisableFboAfterRender(false); > > > > > renderer->getSceneView(1)->getRenderStage()->setDisableFboAfterRender(false); > > > > > > > > m_scene=new osg::Group(); > > > > > > > > std::string modelName="C:\\_JO\\LTI\\SIS\\Models\\test_IR\\carre.flt"; > > > > > > > > LoadModel(modelName); // call m_viewer->SetSceneData > > > > > > > > osg::StateSet* state = m_scene->getOrCreateStateSet(); > > > > > > > > // Disable Lighting effects > > > > state->setMode(GL_LIGHTING, osg::StateAttribute::OVERRIDE | > > osg::StateAttribute::OFF); > > > > > > > > // Enable transparency > > > > state->setMode(GL_BLEND, osg::StateAttribute::OVERRIDE | > > osg::StateAttribute::ON); > > > > // Tell to sort the mesh before displaying it > > > > state->setRenderingHint(osg::StateSet::TRANSPARENT_BIN); > > > > > > > > // Set the blend function (related to the transparency) > > > > osg::BlendFunc* selectedBlendFunction = new osg::BlendFunc(); > > > > selectedBlendFunction->setDestination(GL_ONE_MINUS_SRC_ALPHA); > > > > selectedBlendFunction->setSource(GL_ONE); > > > > > > > > state->setAttribute(selectedBlendFunction, osg::StateAttribute::OVERRIDE > > | osg::StateAttribute::ON); > > > > > > > > osg::Image* offscreenImage = new osg::Image; > > > > osg::ref_ptr<osg::TextureRectangle> offscreenTexture = new > > osg::TextureRectangle; > > > > > > > > // Allocate the image > > > > offscreenImage->allocateImage(WIDTH, HEIGHT, 1, GL_RGBA, GL_FLOAT); > > > > > > > > // Set the 32 bits texture > > > > offscreenTexture->setImage(offscreenImage); > > > > offscreenTexture->setSourceFormat(GL_RGBA); > > > > offscreenTexture->setSourceType( GL_FLOAT); > > > > offscreenTexture->setTextureSize(WIDTH, HEIGHT); > > > > offscreenTexture->setInternalFormat(GL_FLOAT_RGBA32_NV); > > > > > > > > // Initialize the background > > > > camera->setClearColor(osg::Vec4f(0.0f,0.0f,0.0f,1.0f)); > > > > > > > > camera->setRenderTargetImplementation(osg::Camera::FRAME_BUFFER_OBJECT); > > > > camera->attach(osg::Camera::COLOR_BUFFER0,offscreenTexture.get()); > > > > camera->setFinalDrawCallback(new MyCameraDrawCallback(precision)); > > > > > > > > m_viewer->realize(); > > > > > > > > // Set the colors R G > > B A > > > > m_facet1Color = osg::Vec4( 0.2, 0.0, 0.0, > > 1.0 ); > > > > m_facet2Color = osg::Vec4( 0, 0.1, 0.0, > > 1.0 ); > > > > m_facet3Color = osg::Vec4( 4e-6, 0.0, 0.1, > > 1.0 ); > > > > m_facet4Color = osg::Vec4( 5e-5, 0.5, 0.5, > > 1.0 ); > > > > m_facet5Color = osg::Vec4( 6e-9, 0.1, 0.0, 1); > > > > > > > > … > > > > > > > > // Code of my camera Drawcallback > > > > void MyCameraDrawCallback::operator() (osg::RenderInfo& renderInfo) const > > > > { > > > > glReadBuffer(GL_COLOR_ATTACHMENT0_EXT); > > > > m_image->readPixels(0,0,WIDTH,HEIGHT, GL_RGBA,GL_FLOAT); > > > > } > > > > > > > > > > > > > > ------------------------------------------------------------------------ > > > > _______________________________________________ > > osg-users mailing list > > [email protected] > > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > -- > This message is subject to the CSIR's copyright terms and conditions, > e-mail legal notice, and implemented Open Document Format (ODF) standard. > The full disclaimer details can be found at > http://www.csir.co.za/disclaimer.html. > > This message has been scanned for viruses and dangerous content by > MailScanner, > and is believed to be clean. 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