c - Gtk+ and OpenGL bindings

Question

Simple and short: What is the most advanced OpenGL binding for GTK+? I would prefer a widget which allows me to use it similar to QGLWidget.

Note: I stumbled upon gtkglext, gtkglarea and clutter. I read the first two have shortcomings/ serious issues.

Answer 1

Update:

Since Gtk+-3.16 any beyond do not use any of the below!

If you want to use the current state of the art, vertex/pixel shaders you should use the latest gnome and rely on its caps:

Extensively covered in https://www.bassi.io/articles/2015/02/17/using-opengl-with-gtk/

---

Ok, I read pretty much through the last 2 hours and my results are:

• gtkglext will completly replace the backend by OpenGL, this was not my intention
• clutter has all native gl calls boxed into objects and does not support native gl calls at all, though it provides many predifened filters and funny stuff

• gtkglarea seems fine, its design is lovely. It has the same usage style as QGLWidget in Qt (as far as I can say) simple demo of gtkglarea:

  #include <math.h>
  #include <gtk/gtk.h>
  #include <GL/gl.h>
  #include <gtkgl/gtkglarea.h>
  
  int init (GtkWidget *widget)
  {
  if (gtk_gl_area_make_current (GTK_GL_AREA(widget)))
    {
    glViewport(0,0, widget->allocation.width, widget->allocation.height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0,100, 100,0, -1,1);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    }
  
  return TRUE;
  }
  
  int draw (GtkWidget *widget, GdkEventExpose *event)
  {
  if (event->count > 0) return TRUE;
  
  if (gtk_gl_area_make_current (GTK_GL_AREA(widget)))
    {
    glClearColor(0,0,0,1);
    glClear(GL_COLOR_BUFFER_BIT);
    glColor3f(1,1,1);
    glBegin(GL_TRIANGLES);
    glVertex2f(10,10);
    glVertex2f(10,90);
    glVertex2f(90,90);
    glEnd();
    gtk_gl_area_swap_buffers (GTK_GL_AREA(widget));
    }
  
  return TRUE;
  }
  
  int reshape (GtkWidget *widget, GdkEventConfigure *event)
  {
  if (gtk_gl_area_make_current (GTK_GL_AREA(widget)))
    glViewport(0,0, widget->allocation.width, widget->allocation.height);
  
  return TRUE;
  }
  
  int main (int argc, char **argv)
  {
  GtkWidget *window, *glarea;
  
  int attrlist[] = {
  GDK_GL_RGBA,
  GDK_GL_RED_SIZE,1,
  GDK_GL_GREEN_SIZE,1,
  GDK_GL_BLUE_SIZE,1,
  GDK_GL_DOUBLEBUFFER,
  GDK_GL_NONE };
  
  gtk_init (&argc, &argv);
  if (gdk_gl_query () == FALSE) return 0;
  
  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_window_set_title (GTK_WINDOW(window), "Simple");
  gtk_container_set_border_width (GTK_CONTAINER(window), 10);
  g_signal_connect (window, "delete_event",
  G_CALLBACK (gtk_main_quit), NULL);
  
  /* You should always delete gtk_gl_area widgets before exit or else
     GLX contexts are left undeleted, this may cause problems (=core dump)
     in some systems.
     Destroy method of objects is not automatically called on exit.
     You need to manually enable this feature. Do gtk_quit_add_destroy()
     for all your top level windows unless you are certain that they get
     destroy signal by other means. */
  
  gtk_quit_add_destroy (1, GTK_OBJECT(window));
  
  glarea = GTK_WIDGET(gtk_gl_area_new (attrlist));
  gtk_widget_set_size_request (GTK_WIDGET(glarea), 100, 100);
  
  gtk_widget_set_events (GTK_WIDGET(glarea), GDK_EXPOSURE_MASK | GDK_BUTTON_PRESS_MASK);
  
  g_signal_connect (glarea, "expose_event", G_CALLBACK(draw), NULL);
  g_signal_connect (glarea, "configure_event", G_CALLBACK(reshape), NULL);
  g_signal_connect (glarea, "realize", G_CALLBACK(init), NULL);
  
  gtk_container_add (GTK_CONTAINER(window), GTK_WIDGET(glarea));
  gtk_widget_show (GTK_WIDGET(glarea));
  gtk_widget_show (GTK_WIDGET(window));
  
  gtk_main ();
  return 0;
  }
  

Note: gtkglarea has still some problems like core dump on exit (at least 1.99)

Note2: Version 2.0.1 fixes this issue

Edit: For those seeking for 2D only cairo seems to be most suitable.