一些顶点坐标与法向量的知识
osg::ref_ptr<osg::Node> CreateSimple()
{
osg::ref_ptr<osg::Geode> geode=new osg::Geode;
osg::ref_ptr<osg::Geometry> geometry=new osg::Geometry;
//申请一些顶点
osg::ref_ptr<osg::Vec3Array> coords=new osg::Vec3Array;
//申请颜色
osg::ref_ptr<osg::Vec4Array> colors=new osg::Vec4Array;
//申请法向量
osg::ref_ptr<osg::Vec3Array> normals=new osg::Vec3Array;
geode->addDrawable(geometry);
geode->getOrCreateStateSet()->setMode(GL_BLEND,osg::StateAttribute::ON);
//设置顶点
geometry->setVertexArray(coords);
//设置顶点的关联方式
geometry->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::Mode::QUADS,0,4));
//设置顶点颜色
geometry->setColorArray(colors);
geometry->setColorBinding(osg::Geometry::AttributeBinding::BIND_PER_VERTEX);
//设置法向量
geometry->setNormalArray(normals);
geometry->setNormalBinding(osg::Geometry::AttributeBinding::BIND_OVERALL);
//设置顶点
coords->push_back(osg::Vec3(-10.0,5.0,-10.0));
coords->push_back(osg::Vec3(10.0,5.0,-10.0));
coords->push_back(osg::Vec3(10.0,5.0,10.0));
coords->push_back(osg::Vec3(-10.0,5.0,10.0));
//颜色
colors->push_back(osg::Vec4f(1.0,0.0,0.0,0.5));
colors->push_back(osg::Vec4f(0.0,1.0,0.0,0.5));
colors->push_back(osg::Vec4f(0.0,0.0,1.0,0.5));
colors->push_back(osg::Vec4f(1.0,1.0,0.0,0.5));
//压入一个法向量
normals->push_back(osg::Vec3(0.0,-1.0,0.0));
return geode;
}
int main()
{
osg::ref_ptr<osgViewer::Viewer> viewer=new osgViewer::Viewer;
osg::ref_ptr<osg::Group> group=new osg::Group;
group->addChild(osgDB::readNodeFile("glider.osg"));
group->addChild(CreateSimple());
viewer->setSceneData(group);
return viewer->run();
}