Time for action—improving the "Hello World" example_OpenSceneGraph 3.0: Beginner's Guide-QQ阅读男生武侠网

上QQ阅读APP看书，第一时间看更新

Time for action—improving the "Hello World" example

The included headers, <osgDB/ReadFile> and <osgViewer/Viewer>, do not need to be modified. We only add a root variable that provides the runtime access to the Cessna model and assigns it to the setSceneData() method.

In the main entry, record the Cessna model with a variable named root:

osg::ref_ptr<osg::Node> root = osgDB::readNodeFile("cessna.osg");
osgViewer::Viewer viewer;
viewer.setSceneData( root.get() );
return viewer.run();

Build and run it at once:
You will see no difference between this example and the previous "Hello World". So what actually happened?

What just happened?

In this example, we introduced two new OSG classes: osg::ref_ptr<> and osg::Node. The osg::Node class represents the basic element of a scene graph. The variable root stands for the root node of a Cessna model, which is used as the scene data to be visualized.

Meanwhile, an instance of the osg::ref_ptr<> class template is created to manage the node object. It is a smart pointer, which provides additional features for the purpose of efficient memory management.