在球的基礎上進行操作。
效果爲與主窗口和子窗口添加一個邊框
osg::ref_ptr<osg::Vec3Array>vertice2 = new osg::Vec3Array(8);
//外邊界逆針
(*vertice2)[0].set(1,1,0);
(*vertice2)[1].set(w-1,1,0);
(*vertice2)[2].set(w-1,h-1,0);
(*vertice2)[3].set(1,h-1,0);
//內邊界順時針
(*vertice2)[4].set(100,100,0);
(*vertice2)[5].set(100,h-100,0);
(*vertice2)[6].set(w-100,h-100,0);
(*vertice2)[7].set(w-100,100,0);
osg::ref_ptr<osg::Geometry> geom =new osg::Geometry();
geom->setVertexArray(vertice2);
osg::Vec3Array* normals = newosg::Vec3Array;
normals->push_back(osg::Vec3(0.0f,0.0f, 1.0f));
geom->setNormalArray(normals);
geom->setNormalBinding(osg::Geometry::BIND_OVERALL);
osg::Vec4Array* colors = newosg::Vec4Array;
colors->push_back(osg::Vec4(0.0f,0.0f,0.0f,1.0f));
geom->setColorArray(colors);
geom->setColorBinding(osg::Geometry::BIND_OVERALL);
geom->addPrimitiveSet(newosg::DrawArrays(osg::PrimitiveSet::QUADS,0,vertice2->size()));
執行到此處顯然這兩個矩形會覆蓋整個屏幕，需要進行分格化操作。
分格化：
osg::ref_ptr<osgUtil::Tessellator>tscx = new osgUtil::Tessellator();
tscx->setTessellationType(osgUtil::Tessellator::TESS_TYPE_GEOMETRY);
tscx->setBoundaryOnly(false);//設置是否只顯示邊界
tscx->setWindingType(osgUtil::Tessellator::TESS_WINDING_NONZERO);
tscx->retessellatePolygons(*geom);
geode->addDrawable(geom);
//TESS_WINDING_POSITIVE渲染環繞數爲正的區域
//TESS_WINDING_NEGETIVE渲染環繞數爲負的區域
//TESS_WINDING_ODD渲染環繞數爲奇數的區域
//TESS_WINDING_NONZERO渲染環繞數不爲0的區域
//TESS_WINDING_ABS_GEQ_TWO渲染環繞數絕對值大於2的區域
//逆時針爲正，順時針爲負
效果如下：
