2 JPanels, one partly see-through

I want to display a (complicated) background and to display things moving on that background. I thought I could do this by adding one JPanel displaying the background and then adding another JPanel on top of it with the moving bits. I tested this in the following way:

I added the JPanel with the background to a JFrame (center with the borderLayout) and then added another empty JPanel on top of it (by also adding it to the center). However the second JPanel turned out to be opaque, so it simplied showed the empty JPanel on top. My question is, is it possible to make sure that when there is no Color added in some places of the second JPanel that then the bottom JPanel is shown?

You could make the overlaying JPanel non-opaque by calling setOpaque(false) on it. Are you using a JLayeredPane for this as it seems tailor-made for your problem.

Also, when I have a background as you describe, I often draw it in a BufferedImage and simply display that buffered image as the background for my JPanel (the first call in my JPanel's paintComponent method, after super.paintComponent(g) is a call to g.drawImage(myBufferedImage....)), and then draw my dynamic stuff in the same paintComopent but just after the BufferedImage.

This is strange, even when I call setOpaque(false), the JPanel on top still remains opaque. Only when I add the background-pane first is it shown.

I tried adding a paint methode to the JPanel that is supposed to go on top, to see if drawing something on a part of the panel would make the other parts, but the whole JPanel is still opaque. The relevant part of the code:

Code:

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f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                huidigSpel= new spel(this, route, veldGrootte); //making the background
                huidigCreepDisplay = new creepDisplay(huidigSpel);//making the forground
                huidigCreepDisplay.setOpaque(false);//setting the forground opaque
                speelveld.setLayout(new BorderLayout());//adding both of them to a shared JPanel
                speelveld.add("Center", huidigSpel);//adding them to one JPanel together
                speelveld.add("Center", huidigCreepDisplay);
               
                f.add("Center", speelveld);//adding that to the JFrame
                f.pack();

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ps: adding the JPanel's directly to the JFrame instead of to a shared JPanel had ne effect.