Re: [GtkGLExt] reparenting a GtkDrawingArea with OpenGL

[Braden McDaniel <braden endoframe com>]

On Fri, 2009-05-15 at 14:40 -0600, Jeff Eberl wrote:

> I have  a window with two GtkDrawingArea's.  One is a map and one is a
> picture, I'm trying to swap the two windows with the click of a
> button.  Surrounding each drawing is a bunch of buttons and things.  
> 
> This is how I reparent them:
> 
> gtk_widget_ref(map_widget);
> gtk_widget_ref(pic_widget);
> 
> gtk_container_remove(left_
> container, map_widget);
> gtk_container_remove(right_container, pic_widget);
> 
> gtk_container_add(left_container, pic_widget);
> gtk_container_add(right_container, map_widget);
> 
> gtk_widget_unref(map_widget);
> gtk_widget_unref(pic_widget);
> 
> The buttons, the boxes, and everything in the widgets swaps out, but
> the next time I try to draw in either of them, the
> gdk_gl_drawable_gl_begin fails:
> 
> GdkGKExt-CRITICAL **: gdk_gl_window_impl_x11_make_context_current:
> assertion 'GDK_IS_GL_CONTEXT_IMPL_X11 (glcontext)' failed
> 
> So, that's a bummer.  I didn't write the code I'm using to instantiate
> the widgets, or draw the pic/map.  I'm wondering if maybe the problem
> is that the "realize" event gets called twice, but all the gdk setup
> stuff is actually in a different method, one that doesn't get called
> twice.  The realize callback doesn't really have anything in it. 

Hm... Is it getting unrealized? If that happens, and it isn't getting
realized again, that may explain the behavior you're observing.

To debug this, you'd need to track the lifetime of the GdkGLDrawable
that's supposed to be handed off to gdk_gl_drawable_begin; obviously
it's invalid by the time it's getting there.  A stack trace should give
you some starting points for places to put breakpoints.

-- 
Braden McDaniel <braden endoframe com>