Re: building OpenGL under GTK+ using gtkgl

[Tristan Van Berkom <tvb gnome org>]

Dov Kruger wrote:
> Tristan,
>
> Thanks for your response.
> I'm sorry, but I need a bit more concrete help with the blizzard of
> possible API calls.
>
> The original code was simply:
>
> gtk_main();
>
> If I want to invalidate a rectangle, I saw a call, and thought I could
> do something like:
>
>   while (!gtk_main_iteration_do(FALSE)) {
>     cout << "foo\n";
>     gtk_propogate_event(..);
>   }
>
>
> The documentation said not to do this, and I found something, which I am
> not finding now, about invalidating a rectangle.

gdk_window_invalidate_rect/region() will let you do a finer grained
screen update than calling gtk_widget_queue_draw().

Always use `GTK_WIDGET (widget)->window' for your GdkWindow and
`GTK_WIDGET (widget)->allocation' to know what part of that GdkWindow
is allocated to `widget'.

> The call was in gdk though, and this is a gtk widget. In any case, it
> took a gdk rectangle, and while I found a call to construct one, I did
> not find the calls to set the, appropriately. Could you show me how to
> do this, or alternatively, since you have said it's better to use a
> timeout, I take it:
>
> g_idle_add(animate, NULL);
>
> Is this single threaded? Am I guaranteed that it won't be called while
> I'm drawing?

Yes it is single threaded, only one GSource may execute at a time
in one GMainContext (read the Main Event Loop section of the glib
docs).

Cheers,
                        -Tristan