camera movement

Scripting Issues
1

:cry:

i have problem with camera movement and i can’t understand what is happening.

i have a task that move the camera each frame:

        def update(taks):
            self.state.update()
            self.updateCamera()
            self.update_gui()
            return Task.cont
        self.taskMgr.add(update , 'update_state')

in updateCamera i calculate the camera target position and update via getPos():

   def updateCamera(self):

        # define the camera target position
        camera_target_position.x += K.deltax 
        camera_target_position.y = # bla bla bla
        camera_target_position.z += K.deltaz
                
        base.camera.setPos(camera_target_position)

now i want to make movement more fluid using interpolation:

def updateCamera(self):

        # define the camera target position
        camera_target_position.x += K.deltax 
        camera_target_position.y = # bla bla bla
        camera_target_position.z += K.deltaz

        if getattr(self, '_has_interpolation', None):
            self.iPos.setEndPos(camera_target_position)            
        else:
            self._has_interpolation = "already got interpolation!"            
            self.iPos = LerpPosInterval(base.camera, 0.1, camera_target_position)
            self.iPos.start()
            self.iPos.loop()
            print 'first call, create new interpolation'            
        self.iPos.finish()
        self.iPos.start()

but with interpolations… i don’t see my scene and i can’t understand why.
if i try to print base.camera.setPos the coordinates are the same (previous a little time to get interpolated)… but i don’t see anything. someone can give me some advice??