Re: [gl4java-usergroup] Small GLCanvas bug

[Kenneth B. R. <kbr...@al...>]

> The windowClosing method in GLCanvas calls cvsDispose for some reason. 
> In my application I only hide a JFrame instead of disposing it on close 
> (BTW this is default behavior), but this makes the GLCanvas has dispose 
> itself. Now when the JFrame in question is set visible again, the 
> GLCanvas is gone. I commented the entire windowClosing implementation in 
> GLCanvas out and it seems to work fine. Was there any reason this code 
> was put there? It seems to me the GLCanvas will get the windowClosed 
> event when a containing window is disposed, so doing dispose on 
> windowClosing seems unnecessary.

I can't answer this definitively but can probably offer some
insight. The OpenGL context needs to be associated with the
underlying widget/HWND/etc. and discarded at the appropriate
time. The problem (as I understand it) is that by the time the
underlying window has been disposed, it's "too late" to dispose
of the OpenGL context since the associated HWND is gone. This is
probably why the OpenGL context is being disposed of eagerly, in
anticipation that the window might get destroyed. There probably
needs to be some sort of re-initialization code put into place
rather than removal of the context cleanup code, or applications
which really do create and destroy GLCanvas objects will have a
memory leak.