Hi Frédéric, Thanks for your advice. The invisible objects are in the scenegraph before the visible ones so at least I have that going for me. I think we won't be moving the camera view too much so I think it will be OK. I just thought it was weird that I would get the expected behavior until I rotated the camera to some angles and then portions that should be occluded would become visible.
Judie On Apr 16, 7:48 am, Frédéric SPEISSER <[EMAIL PROTECTED]> wrote: > Hi Judie, > > What I noticed using colormask is, if you want some "invisible" objects > (with a colormask to false) to occlude some other objects you must add > the "invisible " ones before the others in the scenegraph. When I say > before it is from the scenegraph traversal point of view. > > I don't know if it can help you... > > Frédéric. > > Judie a écrit : > > > > > > > Hi Robert, > > > I am sorry for not providing an adequate description. > > > High level explanation of what I am trying to do: > > > Replace some of the geometry in the scene with live camera feed. But > > in order to do this, I still need the actual geometry in the scene to > > modify the depth buffer as if it were there even though it is not > > visible. > > > The initial set up for the render states of the scene is: > > > osgUtil::CullVisitor *pCullVisitor = m_sceneView->getCullVisitor(); > > > osgUtil::RenderBin *pRenderBin = pCullVisitor->getCurrentRenderBin(); > > > pRenderBin->setSortMode(osgUtil::RenderBin::SORT_BACK_TO_FRONT); > > > osg::StateSet *pStateSet = m_sceneView->getGlobalStateSet(); > > > pStateSet->setMode(GL_ALPHA_TEST,osg::StateAttribute::OFF); > > > osg::CullFace *pCullFace = new osg::CullFace; > > > pCullFace->setMode(osg::CullFace::BACK); > > > pStateSet->setMode(GL_CULL_FACE, osg::StateAttribute::ON); > > > pStateSet->setAttribute(pCullFace, osg::StateAttribute::ON); > > > osg::ShadeModel *pShadeMdl = new osg::ShadeModel; > > > pShadeMdl->setMode(osg::ShadeModel::FLAT); > > > pStateSet->setAttribute(pShadeMdl, osg::StateAttribute::ON); > > > osg::Depth *pDepth = new osg::Depth; > > > pDepth->setFunction(osg::Depth::LEQUAL); > > > pStateSet->setMode(GL_DEPTH_TEST, osg::StateAttribute::ON); > > > pStateSet->setAttribute(pDepth, osg::StateAttribute::ON); > > > All I do to make some of the geometry not visible and yet still drawn > > to the depth buffer, is disable writes to the color buffer: > > > osg::ColorMask *colormaskOff = new osg::ColorMask(false, false, false, > > false); > > > osg::StateSet* state = node->getOrCreateStateSet(); > > > state->setAttribute(colormaskOff); > > > At another point in the scene graph, I enable writes to the color > > buffer using the same method except the ColorMask values are all true. > > I never disable depth testing. > > > When the scene is rendered, I see my video background and I see my > > objects that should be visible. However, the depth buffer testing does > > not seem to work correctly because some parts of the visible geometry > > that should be occluded by the invisible geometry are showing. But > > this is not uniform. There are times when the visible geometry is > > occluded by the invisible geometry as it should be. > > > If I change the sorting to this: > > > pRenderBin->setSortMode(osgUtil::RenderBin::SORT_FRONT_TO_BACK); > > > then it appears to work until I rotate the camera and then there are > > angles which seem to break the depth testing. > > > What doesn't make sense to me is why the behavior should change at all > > just by disabling writes to the color buffer? I have done the same > > with OpenGL code in a different application, where I was not sorting > > (because there was no transparency) and just relying on the graphics > > drivers\hardware to do the Z buffering, and the occlusion of the > > inivisible objects worked fine. So it seems there must be some > > "optimization" taking place inside the scene graph that is culling > > objects or something. I don't know. It just doesn't make sense to me > > why I can do something in OpenGL and not with OSG. > > > What do you think? > > > Thanks, > > > Judie > > > On Apr 16, 1:57 am, "Robert Osfield" <[EMAIL PROTECTED]> wrote: > > >> Hi Judie, > > >> I'm afraid I've just found it too difficult to work out what you are > >> doing to be able to provide any suggestions. Could you provide a high > >> level explanation of what you are trying to do and why to give a bit > >> of context. Then why you provide code snippets could you space them > >> better as word wrap has made it extremely difficult to read the code. > > >> Robert. > > >> On Tue, Apr 15, 2008 at 11:09 PM, Judie <[EMAIL PROTECTED]> wrote: > > >>> In my code I have an OSG tree with the following global state > >>> attributes defined: > > >>> osgUtil::CullVisitor *pCullVisitor = m_sceneView- > >>> >getCullVisitor(); > >>> osgUtil::RenderBin *pRenderBin = > >>> pCullVisitor->getCurrentRenderBin(); > >>> pRenderBin->setSortMode(osgUtil::RenderBin::SORT_BACK_TO_FRONT); > >>> osg::StateSet *pStateSet = m_sceneView- > >>> >getGlobalStateSet(); > >>> pStateSet->setMode(GL_ALPHA_TEST, > >>> osg::StateAttribute::OFF); > >>> osg::CullFace *pCullFace = new osg::CullFace; > >>> pCullFace->setMode(osg::CullFace::BACK); > >>> pStateSet->setMode(GL_CULL_FACE, osg::StateAttribute::ON); > >>> pStateSet->setAttribute(pCullFace, osg::StateAttribute::ON); > >>> osg::ShadeModel *pShadeMdl = new osg::ShadeModel; > >>> pShadeMdl->setMode(osg::ShadeModel::FLAT); > >>> pStateSet->setAttribute(pShadeMdl, osg::StateAttribute::ON); > >>> osg::Depth *pDepth = new osg::Depth; > >>> pDepth->setFunction(osg::Depth::LEQUAL); > >>> pStateSet->setMode(GL_DEPTH_TEST, osg::StateAttribute::ON); > >>> pStateSet->setAttribute(pDepth, osg::StateAttribute::ON); > > >>> The only other time I change the state is when I enable and disable > >>> the color buffer writes. > > >>> Here is what I am seeing: > >>> If I render the scene with the color buffer always on, then objects > >>> that should be occluded by other objects behave correctly and are > >>> occluded. > > >>> When I render the scene with the color buffer off for some of the > >>> nodes in the beginning of the tree, with it enabled again for ones > >>> later on, I expect that because I DID NOT disable writes to the depth > >>> buffer, that the objects which are occluded by other objects (even > >>> though they were not drawn to the color buffer) should behave > >>> correctly. However, they do not. Some do and some don't and if I > >>> rotate then even ones that behave correctly, begin to misbehave. > > >>> Now I have made the following change because I don't need to worry > >>> about transparency anymore: > >>> pRenderBin->setSortMode(osgUtil::RenderBin::SORT_FRONT_TO_BACK); > > >>> And this almost fixes the issue except if I rotate to some degree, I > >>> still get parts of objects drawn that should be occluded. I know > >>> because I can toggle the objects visible and invisible. > > >>> Is there something internally that can be culling parts of objects > >>> because I have the color buffer masked for them? > > >>> Thanks, > > >>> Judie > >>> _______________________________________________ > >>> osg-users mailing list > >>> [EMAIL PROTECTED] > >>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph... > > >> _______________________________________________ > >> osg-users mailing list > >> [EMAIL > >> PROTECTED]://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph...Hide > >> quoted text - > > >> - Show quoted text - > > > _______________________________________________ > > osg-users mailing list > > [EMAIL PROTECTED] > >http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph... > > _______________________________________________ > osg-users mailing list > [EMAIL > PROTECTED]://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph...- > Hide quoted text - > > - Show quoted text - _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
