求助:给矩形添加轮廓线的时候遇到了问题

zhhtj

我是个OSG初学者，仿照osgoutline的例子显示box轮廓线正常，代码如下：

1. int main(int argc, char **argv)
   
2. {
   
3.         osg::ref_ptr<osg::Geode> geode = new osg::Geode;  
   
4.         geode->addDrawable(new osg::ShapeDrawable(new osg::Box(osg::Vec3(), 2)));
   
5.        
   
6.         osg::ref_ptr<osg::Group> root = new osg::Group;
   
7.         osg::ref_ptr<osgFX::Outline> outline = new osgFX::Outline;
   
8.         root->addChild(outline.get());
   
9.         outline->setWidth(8);
   
10.         outline->setColor(osg::Vec4(1,1,0,1));
    
11.         outline->addChild(geode.get());
    
12. 
    
13.         // must have stencil buffer...
    
14.         osg::DisplaySettings::instance()->setMinimumNumStencilBits(1);
    
15. 
    
16.         // construct the viewer
    
17.         osgViewer::Viewer viewer;
    
18.         viewer.setSceneData(root.get());
    
19. 
    
20.         // must clear stencil buffer...
    
21.         unsigned int clearMask = viewer.getCamera()->getClearMask();
    
22.         viewer.getCamera()->setClearMask(clearMask | GL_STENCIL_BUFFER_BIT);
    
23.         viewer.getCamera()->setClearStencil(0);
    
24.         viewer.setUpViewInWindow(100, 100, 800, 600);
    
25.         return viewer.run();
    
26. }

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box

但是我想画一个矩形的轮廓线，main函数前两句改为

1. osg::ref_ptr<osg::Geometry> geom = new osg::Geometry;
   
2.         osg::ref_ptr<osg::Vec3Array> v = new osg::Vec3Array;
   
3.         v->push_back(osg::Vec3(1, 1, 1));
   
4.         v->push_back(osg::Vec3(2, 1, 1));
   
5.         v->push_back(osg::Vec3(2, 2, 1));
   
6.         v->push_back(osg::Vec3(1, 2, 1));
   
7.         geom->setVertexArray(v.get());
   
8.         osg::ref_ptr<osg::DrawElementsUInt> quad = new osg::DrawElementsUInt(osg::PrimitiveSet::QUADS, 0);
   
9.         quad->push_back(0);
   
10.         quad->push_back(1);
    
11.         quad->push_back(2);
    
12.         quad->push_back(3);
    
13.         geom->addPrimitiveSet(quad.get());
    
14.         osg::ref_ptr<osg::Vec4Array> c = new osg::Vec4Array;
    
15.         c->push_back(osg::Vec4(1, 0, 0, 1));
    
16.         geom->setColorArray(c.get());
    
17.         geom->setColorBinding(osg::Geometry::BIND_OVERALL);
    
18.         osg::ref_ptr<osg::Vec3Array> n = new osg::Vec3Array;
    
19.         n->push_back(osg::Vec3(0, 0, 1));
    
20.         geom->setNormalArray(n.get());
    
21.         geom->setNormalBinding(osg::Geometry::BIND_OVERALL);
    
22.         osg::ref_ptr<osg::Geode> geode = new osg::Geode;
    
23.         geode->addDrawable(geom.get());

复制代码

矩形下方可以正常显示轮廓线，但是矩形上方无法显示

下方

上方

请大家帮我看看问题出在哪里？谢谢