public void setInvertVerticalAxis(boolean invertYaxis) {
        this.invertYaxis = invertYaxis;
        inputManager.deleteMapping(CameraInput.CHASECAM_DOWN);
        inputManager.deleteMapping(CameraInput.CHASECAM_UP);
        if (!invertYaxis) {
            inputManager.addMapping(CameraInput.CHASECAM_DOWN, new MouseAxisTrigger(MouseInput.AXIS_Y, true));
            inputManager.addMapping(CameraInput.CHASECAM_UP, new MouseAxisTrigger(MouseInput.AXIS_Y, false));
        } else {
            inputManager.addMapping(CameraInput.CHASECAM_DOWN, new MouseAxisTrigger(MouseInput.AXIS_Y, false));
            inputManager.addMapping(CameraInput.CHASECAM_UP, new MouseAxisTrigger(MouseInput.AXIS_Y, true));
        }
        inputManager.addListener(this, CameraInput.CHASECAM_DOWN, CameraInput.CHASECAM_UP);
    }
invert the vertical axis movement of the mouse

@param invertYaxis true&rarr;invert, false&rarr;don't invert
jme3-core/src/main/java/com/jme3/input/ChaseCamera.java