Re: [GtkGLExt] first call of gdk_gl_drawable_gl_begin fails

[jlm <jsado_sc4 earthlink net>]

I think the first thing you need to do is get simple.c working. Does it 
work if you disable hardware rendering?
Set this before running our program:

export GDK_GL_FORCE_INDIRECT=1

Also you can set other variables and command-line switches to get 
additional debug info. See

http://gtkglext.sourceforge.net/reference/gtkglext/gtkglext-running.html

Alexander Nagel wrote:
> Hi all,
> i have a little program with a gtkgl capable drawing area just like in
> various example programs.
>
> But i have a problem:
>
> The first call of 
> GdkGLContext *glcontext = gtk_widget_get_gl_context (object);
> GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable (object);
> gdk_gl_drawable_gl_begin (gldrawable, glcontext)
> in the configure_event callback always fails with this message:
>
> GdkGLExt-CRITICAL **: file gdkgldrawable.c: line 141
> (gdk_gl_drawable_gl_begin): assertion `GDK_IS_GL_DRAWABLE (gldrawable)'
> failed
>
> Further calls of this function work normal.
> I can avoid this by adding
> if ( ! GDK_IS_GL_DRAWABLE( object ) ) return FALSE;
>
> So far i didn't manage to anything opengl specific in the drawing area.
> Even the simpliest thing like in simple.c in the gtkgl examples don't
> work.
> Is it normal that the first call fails?
> Is this the reason that i can't render opengl things in the area?
>
> Thanks for any hints
> Alex
>
>
> Here is the callback function
>
> gboolean on_drawingarea1_configure_event (GtkWidget *object,
> GdkEventConfigure *event, gpointer user_data)
> {
> 	GdkGLContext *glcontext;
> 	GdkGLDrawable *gldrawable;
> 	baf_log ("configure");
> 	if (!GTK_WIDGET_REALIZED (object)) 
> 		return FALSE;
> 	if (!GDK_IS_GL_DRAWABLE(object))
> 		return FALSE;
> 	glcontext = gtk_widget_get_gl_context (object);
> 	gldrawable = gtk_widget_get_gl_drawable (object);
> 	if (!gdk_gl_drawable_gl_begin (gldrawable, glcontext))
> 	{
> 		g_print ("no draw in configure\n");
> 		return FALSE;
> 	}
> 	baf_ogl->change_viewport (object->allocation.width,
> object->allocation.height);	
> 	gdk_gl_drawable_gl_end (gldrawable);
> 	return TRUE;
> 	
>
> }
>
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