In the 3D scene, when we click a 3D object by mouse, we can get the
exact mouse position on the object's surface by (MouseEvent3D.sceneX,
MouseEvent3D.sceneY, MouseEvent3D.sceneZ). I guess some functions in
MouseEvent3D.as or Event.as explore all triangles of the mesh clicked,
and use ray-plane interception method to calculate the mouse position
in 3D space. However, I can not find these functions. I also read the
Mesh.as and Object3D.as files, but failed to find anything. Does
anyone know how it works? I want to find a way to get the triangle
clicked. Thanks!
