//static Standard_Real MyXwindowCenter ;
//static Standard_Real MyYwindowCenter ;
//static Standard_Real MyWindowWidth ;
//static Standard_Real MyWindowHeight ;
static Graphic3d_Vector MyXscreenAxis ;
static Graphic3d_Vector MyYscreenAxis ;
static Graphic3d_Vector MyZscreenAxis ;
static Graphic3d_Vector MyViewReferencePlane ;
static Graphic3d_Vector MyViewReferenceUp ;
static Graphic3d_Vector MyViewAxis ;
static Graphic3d_Vertex MyViewReferencePoint ;
static Graphic3d_Vertex MyGravityReferencePoint ;
static Graphic3d_Vertex MyProjReferencePoint ;