def initializeGL(self):
        '''
        Initialise the Zinc scene for drawing the axis glyph at a point.  
        '''
        # Following throws exception if you haven't called setContext() yet
        SceneviewerWidget.initializeGL(self)
        if self._sceneviewer and self._sceneviewer.isValid():
            scene = self._sceneviewer.getScene()
            graphics_filter = self._sceneviewer.getScenefilter()
            self._scenepicker = scene.createScenepicker()
            region = scene.getRegion()

            fieldmodule = region.getFieldmodule()

            self._selectionGroup = fieldmodule.createFieldGroup()
            scene.setSelectionField(self._selectionGroup)

            self._scenepicker = scene.createScenepicker()
            self._scenepicker.setScenefilter(graphics_filter)
            sceneFilterModule = self.getContext().getScenefiltermodule()
            self._sceneSurfacesFilter = sceneFilterModule.createScenefilterOperatorAnd(
            )
            surfacesFilter = sceneFilterModule.createScenefilterGraphicsType(
                Graphics.TYPE_SURFACES)
            self._sceneSurfacesFilter.appendOperand(graphics_filter)
            self._sceneSurfacesFilter.appendOperand(surfacesFilter)
            self.createSelectionBox(scene)
    def initializeGL(self):
        '''
        Initialise the Zinc scene for drawing the axis glyph at a point.  
        '''
        # Following throws exception if you haven't called setContext() yet
        SceneviewerWidget.initializeGL(self)
        if self._sceneviewer and self._sceneviewer.isValid():
            scene = self._sceneviewer.getScene()
            graphics_filter = self._sceneviewer.getScenefilter()
            self._scenepicker = scene.createScenepicker()
            region = scene.getRegion()

            fieldmodule = region.getFieldmodule()

            self._selectionGroup = fieldmodule.createFieldGroup()
            scene.setSelectionField(self._selectionGroup)

            self._scenepicker = scene.createScenepicker()
            self._scenepicker.setScenefilter(graphics_filter)
            sceneFilterModule = self.getContext().getScenefiltermodule()
            self._sceneSurfacesFilter = sceneFilterModule.createScenefilterOperatorAnd()
            surfacesFilter = sceneFilterModule.createScenefilterGraphicsType(Graphics.TYPE_SURFACES)
            self._sceneSurfacesFilter.appendOperand(graphics_filter)
            self._sceneSurfacesFilter.appendOperand(surfacesFilter)
            self.createSelectionBox(scene)