Hello everyone, I'm trying to use stencils and I'm not sure what I'm missing. Basically I have two quads in my scene. I want the quad two to set the stencil buffer to 1, and I want the quad one to be visible only where the stencil buffer is not 1.
So far I am getting the result which I want if I don't clear the stencil buffer. Of course in that case when I rotate the scene using the viewer, the stencil buffer gets painted to 1's(because of the quad two) and I don't see the quad one even on places where quad two is not positioned anymore. However when I clean the stencil buffer(see below), I don't get the result that I want. > viewer->getCamera()->setClearMask(GL_COLOR_BUFFER_BIT | > GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); In this case both of the quads are visible. I'm suspecting that the stencil buffer gets cleared before the stencil check is done. Here is a part of my code where I set the stencils. > osg::ref_ptr<osg::PositionAttitudeTransform> transform_one = new > osg::PositionAttitudeTransform(); > osg::ref_ptr<osg::PositionAttitudeTransform> transform_two = new > osg::PositionAttitudeTransform(); > transform_one->addChild(createQuad()); > transform_two->addChild(createQuad()); > transform_two->setScale(osg::Vec3(0.5, 0.5, 0.5)); > transform_two->setPosition(osg::Vec3(0.25, 0.2, 0.25)); > > // --- Begin stencil related stuff > osg::ref_ptr<osg::StateSet> ss_one = transform_one->getOrCreateStateSet(); > osg::ref_ptr<osg::StateSet> ss_two = transform_two->getOrCreateStateSet(); > osg::ref_ptr<osg::Stencil> stencil_one = new osg::Stencil(); > osg::ref_ptr<osg::Stencil> stencil_two = new osg::Stencil(); > stencil_two->setFunction(osg::Stencil::ALWAYS, 1, ~0u); > stencil_two->setOperation(osg::Stencil::KEEP, osg::Stencil::KEEP, > osg::Stencil::REPLACE); > stencil_one->setFunction(osg::Stencil::NOTEQUAL, 1, ~0u); > stencil_one->setOperation(osg::Stencil::KEEP, osg::Stencil::KEEP, > osg::Stencil::KEEP); > ss_one->setMode(GL_LIGHTING, osg::StateAttribute::OFF); > ss_two->setMode(GL_LIGHTING, osg::StateAttribute::OFF); > osg::ref_ptr<osg::ColorMask> cm_one = new osg::ColorMask(); > // I play with the parameters below to see the position of the quad two cm_one->setMask(false, false, false, false); > ss_two->setAttribute(cm_one); > ss_two->setAttributeAndModes(stencil_two, osg::StateAttribute::ON | > osg::StateAttribute::OVERRIDE); > ss_one->setAttributeAndModes(stencil_one, osg::StateAttribute::ON | > osg::StateAttribute::OVERRIDE); Any help would be appreciated, I am sure I'm missing something really basic :) Thanks
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