Well, with Java, you have to place the applet in your webpage in order for your jogl program to even have something to run in. Which means that even if you set your GL context clear color to be completely transparent, all you’d see is the background for your applet, so you still don’t get anything from that. However I don’t know how you got your c++ stuff to work directly with the browser as the drawable, but if it was the way I think it was, jogl also allows you to grab external OpenGL contexts and use them in java, so you could try that and see if that gives you any results. Mind you, I’ve never used this functionality, so I could be mistaken, it could be faulty/broken, or it might work beautifully.