public void setInvertVerticalAxis(boolean invertYaxis) {
        this.invertYaxis = invertYaxis;
        if (inputManager != null) {
            inputManager.deleteMapping(CameraInput.CHASECAM_DOWN);
            inputManager.deleteMapping(CameraInput.CHASECAM_UP);
            initVerticalAxisInputs();
            inputManager.addListener(this, CameraInput.CHASECAM_DOWN, CameraInput.CHASECAM_UP);
        }
    }
invert the vertical axis movement of the mouse

@param invertYaxis true&rarr;inverted, false&rarr;not inverted
jme3-core/src/main/java/com/jme3/app/ChaseCameraAppState.java