@Override
    public Matrix4f getHMDMatrixProjectionLeftEye(Camera cam){
        if( hmdProjectionLeftEye != null ) {
            return hmdProjectionLeftEye;
        } else if(vrSystemFunctions == null){
            return cam.getProjectionMatrix();
        } else {
            HmdMatrix44_t mat = vrSystemFunctions.GetProjectionMatrix.apply(JOpenVRLibrary.EVREye.EVREye_Eye_Left, cam.getFrustumNear(), cam.getFrustumFar());
            hmdProjectionLeftEye = new Matrix4f();
            convertSteamVRMatrix4ToMatrix4f(mat, hmdProjectionLeftEye);
            return hmdProjectionLeftEye;
        }
    }
Initialize the headset camera.
@param allowed <code>true</code> is the use of the headset camera is allowed and <code>false</code> otherwise.
jme3-vr/src/main/java/com/jme3/input/vr/openvr/OpenVR.java