此示例演示如何使用vsTraversalUser写一个用户定义的场景图的遍历的VSG。它定义了类MyApp，这是从vsApp而得。样品装载镇数据库，并启动一个遍历计数所有在场景图中的不同节点类型。-Traversal VSG This example demonstrates how to use vsTraversalUser write a user-defined scene graph. It defines the class MyApp, which is derived from vsApp. Sample loading Town database and start a count of all the different node types traversing the scene graph.