奇怪的DrawArray,求教

acmiyou

1.         osg::Geode* geode = new osg::Geode;
   
2.         osg::Geometry* nowGeom = new osg::Geometry;
   
3.         nowGeom->addPrimitiveSet(new osg::DrawArrays(GL_POINTS,0,2));
   
4. 
   
5.         osg::Vec3Array* color2 = new osg::Vec3Array;
   
6.         color2->push_back(osg::Vec3(0.0,1.0,1.0));
   
7.         nowGeom->setColorBinding(osg::Geometry::BIND_OVERALL);
   
8.         nowGeom->setColorArray(color2);
   
9. 
   
10.         osg::Vec3Array* vertex = new osg::Vec3Array;
    
11.         nowGeom->setVertexArray(vertex);
    
12.         vertex->push_back(osg::Vec3(600,600,0));
    
13.         vertex->push_back(osg::Vec3(600,400,0));
    
14.         nowGeom->setDataVariance(osg::Object::DYNAMIC);
    
15. 
    
16.         osg::StateSet* state2 = nowGeom->getOrCreateStateSet();
    
17.         osg::Point* point = new osg::Point;
    
18.         point->setSize(5.0);
    
19.         state2->setAttributeAndModes(point);
    
20.         state2->setMode(GL_DEPTH_TEST,osg::StateAttribute::OFF);
    
21. 
    
22.         geode->addDrawable(nowGeom);

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我将它设置成2个顶点确实可以看到两个顶点.
而修改成一个顶点的时候的即:

1. nowGeom->addPrimitiveSet(new osg::DrawArrays(GL_POINTS,0,1));

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应当是会绘制一个顶点的啊?可是却没有绘制出来?
如下图: 附件
而我在OpenGL里 使用glDrawArray(GL_POINTS,0,1)绘制一个顶点确实可以绘制的出来

array

OSG有一个默认的“细节裁减”设定，就是单个顶点会被自动裁减掉，因为它们对于场景显示很可能是不必要的。可以关闭这个设定，例如：
viewer.getCamera()->setCullingMode( viewer.getCamera()->getCullingMode() & ~osg:: CullStack:: SMALL_FEATURE_CULLING);

billong

2# array


学习了。。。。呵呵