Re: Threaded animation with cairo_gl backend over a GtkWidget

Thanks Henry, I'll give it a try.


2013/1/11 Henry (Yu) Song - SISA <[email protected]>

> Hi,
>
> Please add XInitThreads() in your main.  For multithreaded application
> using gl_surface is not a good idea for the moment unless you have
> intel/radeon/nouveau drivers, otherwise, you will have very sloooooow
> performance.
>
> We will resolve that soon in cairo for gl backend, I hope.
>
> Henry
> ________________________________________
> From: [email protected][cairo-bounces+henry.song=
> [email protected]] on behalf of Carlos López González [
> [email protected]]
> Sent: Thursday, January 10, 2013 11:26 AM
> To: [email protected]
> Subject: [cairo] Threaded animation with cairo_gl backend over a GtkWidget
>
> Hi!
> I've made a modified version [1] of the example of threaded animation
> using Cairo [2].
>
> First I've used the method to create a cairo_gl_surface from the
> test/gl_source_surface.c file adapted to create the surface for a given
> widget instead for a defined size.
>
> Also, for simplicity, I removed all the handled signals except the destroy
> one.
>
> To handle the drawing for the window widget using the cairo_gl backend I
> use the create_gl_surface_for_window function passing it the proper widget
> information.
>
> So far, for a single drawing execution it works as expected:
> 1) In main() create the window_surface
> 2) The do_draw function creates a context based on window_surface
> 3) Once done the drawings with Cairo then the buffers are swapped and the
> content is shown on screen.
>
> Notice that the window_surface is never destroyed explicitly because it is
> owned by the window widget and so it will be destroyed when the window is
> destroyed by gtk.
>
> The problem comes when I enable the multithreading support by uncommenting
> the line:
>
>
> //(void)g_timeout_add(33, (GSourceFunc)timer_exe, window);
>
> It triggers the timer_exe function 33 times per second and then it creates
> threads that will call do_draw each time.
>
> Once enabled it crashes at the first painting function from Cairo.
>
> I believe that the problem is that the window_surface belongs to the
> window widget when I created it and then I can't modify it outside the main
> gtk thread.
>
> How can I solve this? If I enclose the Cairo painting operations inside a
> gdk_threads_enter and
> gdk_threads_leave I would add a lot of time consuming operations to the
> main gtk thread, which is precisely what I want to avoid using
> multithreading.
>
> Any help? I would like to know at last, if my assumptions of the
> window_surface ownership are true or not.
>
> Thanks!
>
> [1]
> https://github.com/genete/my-test-area/blob/direct_draw/src/cairo_sample.c
> [2] http://cairographics.org/threaded_animation_with_cairo/
>
> --
> Carlos
> http://synfig.org
>



-- 
Carlos
http://synfig.org

-- 
cairo mailing list
[email protected]
http://lists.cairographics.org/mailman/listinfo/cairo