protected void destroyPbuffer() {
        if (pbuffer != null) {
            if (!pbuffer.isBufferLost()) {
                pbuffer.destroy();
            }
            pbuffer = null;
        }
    }
Makes sure the pbuffer is available and ready for use

@throws LWJGLException if the buffer can't be made current
jme3-lwjgl/src/main/java/com/jme3/system/lwjgl/LwjglCanvas.java