[vtkusers] How can i get the mouse position? GetMousePosition?

[BoShi]

 hi，

In the following source code ,

vtkRenderWindowInteractor* iren =
vtkRenderWindowInteractor::SafeDownCast(caller);
vtkRenderer* renderer = (vtkRenderer*)clientdata;

vtkWorldPointPicker* picker = vtkWorldPointPicker::New();
double pickCoords[3];

int mouseX,mouseY;
iren->GetMousePosition(&mouseX, &mouseY);
picker->Pick(mouseX, mouseY, 0.0, renderer);
picker->GetPickPosition(pickCoords);


picker->Delete();


I debug these code I found the mouseX and mouseY got from
GetMousePosition are constant and doesn't change while I' changing the
mouse double click. Why?

Who can tell me? Thanks a lot!