backBuffers = new VolatileImage[num];
GraphicsConfiguration c = GraphicsEnvironment.getLocalGraphicsEnvironment() .getDefaultScreenDevice().getDefaultConfiguration();  backBuffers = new VolatileImage[numBuffers];  for (int i = 0; i < numBuffers; i++) backBuffers[i] = c.createCompatibleVolatileImage(width, height);
    protected void createBackBuffers(int num)    {			backBuffers = new VolatileImage[num];		}