[GtkGLExt] Force Rendering

[Matthew A Tobiasz <matobias ucalgary ca>]

Hello,

I have a bunch of GtkDrawingArea's where I'm doing my openGL rendering, and I 
want to have things such that when a GtkButton is pressed  a specific window 
is render. What I'm doing is having this "zoom button" modify the projection 
matrix used for rendering the scene.

Here's what I've got:

void zoom_button_callback(GtkWidget *widget, gpointer ptr){
	da = GTK_WIDGET(ptr); // ptr points to a opengl capable drawing area 

	... modify the projection matrix ...
	
	gdk_window_invalidate_rect (da->window, &da->allocation, FALSE);
	gdk_window_process_updates (da->window, FALSE);
}

Now this works for the first drawing area, but the not the other ones.  Any 
ideas.....

-Matthew