[gtkada] More newbie stuff

[Michael Andersson]

Hi (again) ! :-)
I've included the code this time to make it more clear to what I'm
after.
Update is the Idle-callback function and I want it to call Display after

it is done with the update.
As I see it I have two choises:
Either I redraw the widget or I can pass an expose_event to the
Gtk_Glarea -widget.
Can somebody please show me how to do this?

Thanks!
/Michael Andersson

with Ada.Text_IO;      use Ada.Text_IO;
with GL_H;             use GL_H;
with Gdk.Event;        use Gdk.Event;
with Gdk.GL;           use Gdk.GL;
with Gdk.Types;        use Gdk.Types;
with Gdk.Window;       use Gdk.Window;
with Glib;             use Glib;
with Glu_H;            use Glu_H;
with Gtk.Glarea;       use Gtk.Glarea;
with Gtk.Handlers;     use Gtk.Handlers;
with Gtk.Main;          use Gtk.Main;
with Gtk.Widget;        use Gtk.Widget;
package body Setup_GL is

   --type MyGLArea is access all Gtk_Glarea_Record;

   package EventRCB is new Gtk.Handlers.Return_Callback
(Gtk_Glarea_Record, Boolean);
   package EventCB is new Gtk.Handlers.Callback (Gtk_Glarea_Record);

   package MyIdle is new Gtk.Main.Idle(Gtk_glarea);

   function Init(Area : access Gtk_Glarea_Record'Class)
                 return Boolean is
   begin
      if Make_Current(Area) then
         Glclearcolor(0.0,0.0,0.0,0.0);
         Glenable(GL_DEPTH_TEST);
         Glshademodel(GL_SMOOTH);
      end if;
      return True;
   end Init;

   function Display (Area  : access Gtk_Glarea_Record'Class;
                     Event : Gdk_Event)
                     return Boolean is
   begin
      if Get_Count(Event) > 0 then
         return True;
      end if;

      if Make_Current(Area) then
         Put_Line("Display");
         Glclear(GL_COLOR_BUFFER_BIT);
         Glclear(GL_DEPTH_BUFFER_BIT);
         Glloadidentity;
         Gltranslatef(0.0,0.0,-15.0);
         Glbegin(GL_QUADS);
         Glvertex3f(-2.0,0.0,0.0);
         Glvertex3f(-2.0,2.0,0.0);
         Glvertex3f(2.0,2.0,0.0);
         Glvertex3f(2.0,0.0,0.0);
         Glend;
         Swap_Buffers(Area);
      end if;
      return True;
   end Display;

   function Reshape (Area : access Gtk_Glarea_Record'Class;
                       Event : Gdk_Event)
                      return Boolean is
      Window : Gdk.Window.Gdk_Window;
      Width : Gint;
      Height : Gint;
     begin
        if Make_Current(Area) then
           Window := Get_Window(Event);
           Get_Size(Window,Width,Height);
           Glviewport(0,0,Integer(Width),Integer(Height));
           Glmatrixmode(GL_PROJECTION);
           Glloadidentity;
           Gluperspective(Long_Float (45.0),Long_Float(Width/Height),
1.0,100.0);
           Glmatrixmode(GL_MODELVIEW);
           Glloadidentity;
        end if;
      return True;
   end Reshape;

   procedure GlArea_Destroy (Area : access Gtk_Glarea_Record'Class)
   is
   begin
      Put_Line("Destroy called");
   end GlArea_Destroy;

   function Update(Area : Gtk_GLArea) return Boolean is
   begin
      return True;
   end Update;

   procedure Setup (Window : access Gtk_Window_Record'Class) is
      Area : Gtk_Glarea;
      Id : Idle_Handler_Id;
   begin
      if not Gdk.GL.Query then
         Put_Line ("OpenGL not supported");
         return;
      end if;

      Gtk_New(Area, (GDK_GL_RGBA,
                   GDK_GL_RED_SIZE, Gl_Configs (1),
                   GDK_GL_GREEN_SIZE, Gl_Configs (1),
                   GDK_GL_BLUE_SIZE, Gl_Configs (1),
                   GDK_GL_DOUBLEBUFFER,
                   GDK_GL_DEPTH_SIZE, Gl_Configs (1)));
      if Area = null then
         Put_Line ("Can't create Gtk_GLArea widget");
         return;
      end if;

      Set_Events (Area, Exposure_Mask);

      EventRCB.Connect (Area, "realize",
                        EventRCB.To_Marshaller (Init'Access));
      EventRCB.Connect (Area, "expose_event",
                        EventRCB.To_Marshaller (Display'Access));
      EventRCB.Connect(Area, "configure_event",
                       EventRCB.To_Marshaller (Reshape'Access));
      EventCB.Connect (Area, "destroy",
                       EventCB.To_Marshaller (Glarea_Destroy'Access));

      Id :=  MyIdle.Add(Update'Access, Area);
      Add (Window, Area);
      Show_All (Window);
   end Setup;

  end Setup_GL;