Yes, the openGL code enabled the back face culling. I think I didn't do this in osg, my bad. Where should I look for back face culling in osg? Something in example? Thanks!
Ruqin 2009/3/18 Robert Osfield <[email protected]> > Hi Ruqin, > > I'm not going to review your code as it's pointless, it's not seeing the > wood from the trees. Answer the question I asked, is it back face culling > that you are talking about?? In your OpenGL app did you enable/disable back > face culling? > > Robert. > > > 2009/3/18 Ruqin Zhang <[email protected]> > >> Sorry about the confusion. Here is the openGL code that works: >> >> *triangle t;* >> * const float* pFltArrayN = t.getNormal();* >> * const float* pFltArray1 = t.getVert1();* >> * const float* pFltArray2 = t.getVert2();* >> * const float* pFltArray3 = t.getVert3();* >> >> * glNormal3fv(pFltArrayN);* >> * glVertex3fv(pFltArray1);* >> * glVertex3fv(pFltArray2);* >> * glVertex3fv(pFltArray3);* >> * * >> * a[0] = -pFltArrayN[0];* >> * a[1] = -pFltArrayN[1];* >> * a[2] = -pFltArrayN[2];* >> * glNormal3fv(a);* >> * glVertex3fv(pFltArray3);* >> * glVertex3fv(pFltArray2);* >> * glVertex3fv(pFltArray1);* >> >> I tried to do the same thing in osg, here is my code: >> >> *osg::ref_ptr<osg::Material> material = new osg::Material(); >> >> material->setEmission(osg::Material::FRONT_AND_BACK,osg::Vec4f(0.00f,0.00f,0.00f,0.00f)); >> osg::ref_ptr<osg::PolygonMode> polymode = new osg::PolygonMode(); >> >> polymode->setMode(osg::PolygonMode::FRONT_AND_BACK,osg::PolygonMode::FILL); >> osg::ref_ptr<osg::StateSet> stateset = new osg::StateSet(); >> >> stateset->setAttributeAndModes(material.get(),osg::StateAttribute::OVERRIDE|osg::StateAttribute::ON); >> >> stateset->setAttributeAndModes(polymode.get(),osg::StateAttribute::OVERRIDE|osg::StateAttribute::ON); >> >> stateset->setMode(GL_LIGHTING,osg::StateAttribute::OVERRIDE|osg::StateAttribute::ON); >> >> stateset->setTextureMode(0,GL_TEXTURE_2D,osg::StateAttribute::OVERRIDE|osg::StateAttribute::OFF); >> * >> >> *for(int j = 0; j < mesh->getNumTriangles(); j ++)* >> *{* >> * osg::DrawElementsUInt* frontTriElement = new >> osg::DrawElementsUInt(osg::PrimitiveSet::TRIANGLES,0);* >> * frontTriElement->push_back(mesh->getTri(j).getVert1Index());* >> * frontTriElement->push_back(mesh->getTri(j).getVert2Index());* >> * frontTriElement->push_back(mesh->getTri(j).getVert3Index());* >> * meshGeometry->addPrimitiveSet(frontTriElement);* >> * osg::Vec3f normalVec(mesh->getTri(j).getNormalVec3().x, >> mesh->getTri(j).getNormalVec3().y,* >> * >> mesh->getTri(j).getNormalVec3().z);* >> * normalArray->push_back(normalVec);* >> >> * osg::DrawElementsUInt* backTriElement = new >> osg::DrawElementsUInt(osg::PrimitiveSet::TRIANGLES,0);* >> * backTriElement->push_back(mesh->getTri(j).getVert3Index());* >> * backTriElement->push_back(mesh->getTri(j).getVert2Index());* >> * backTriElement->push_back(mesh->getTri(j).getVert1Index());* >> * meshGeometry->addPrimitiveSet(backTriElement);* >> * normalArray->push_back(-normalVec);* >> *}* >> *meshGeometry->setStateSet(stateset.get());* >> *meshGeometry->setVertexArray(vertexArray.get());* >> *meshGeometry->setNormalArray(normalArray.get());* >> *meshGeometry->setNormalBinding(osg::Geometry::BIND_PER_PRIMITIVE);* >> >> While seems this doesn't work. Any problem or mistake? Thanks a lot! >> >> Ruqin >> >> >> 2009/3/18 Robert Osfield <[email protected]> >> >>> Hi Ruqin, >>> >>> >>> 2009/3/18 Ruqin Zhang <[email protected]> >>> >>>> Thanks Robert. Alright, here is the deal. I'm trying to draw a 3D >>>> triangular mesh with osg. For some mesh, the calculated normal points >>>> to the inside. So, I want to draw both the front and back faces, which >>>> have opposite normals. Then you can render the mesh visible. >>>> Is there an example of this? Thanks! >>>> >>> >>> Are you talking about two face lighting of back face culling here?? >>> Originally your email sounded like you were talking about lighting at back >>> face culling has nothing to do with normals, but this new emails sounds like >>> you might be refering to back face culling... >>> >>> Robert. >>> >>> _______________________________________________ >>> 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 >> >> > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > >
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