Hello,

GLScene flickers in GTK2 and the following patch fixes this

Index: lcl/interfaces/gtk/gtkwinapiwindow.pp
=================================================================== --- lcl/interfaces/gtk/gtkwinapiwindow.pp (revision 17040) +++ lcl/interfaces/gtk/gtkwinapiwindow.pp (working copy) @@ -484,7 +484,7 @@

  //@  gtk_widget_set_flags(AWidget, GTK_REALIZED);

    {$IFNDEF GTK1}
-  gtk_widget_set_double_buffered(AWidget, True); // True bites caret => ToDo
+  gtk_widget_set_double_buffered(AWidget, False); // True bites caret => ToDo
    gtk_widget_set_redraw_on_allocate(AWidget, False);
    {$ENDIF}

In Lazarus svn 15362 Mattias changed "gtk_widget_set_double_buffered" from False to True (with decription "gtk2 intf: moved doublebuffering from synedit to gtk2 as this is faster since gtk2.12"), is this really needed?

If Lazarus cannot be changed, does anyone have any idea on how to fix this in GLScene?

Regards,
Paulo

In Lazarus svn 15362 Mattias changed "gtk_widget_set_double_buffered" from False to True (with decription "gtk2 intf: moved doublebuffering from synedit to gtk2 as this is faster since gtk2.12"), is this really needed?

IMHO yes. Speeding up synedit is always a good idea. I think the problem is that OpenGL contexts should not be double buffered by gtk. OpenGL does the buffering (single, double, triple, quad) itself depending on user choice and hardware support. Therefor any OpenGL widgets should only be single buffered by the widget set. I don't know anything about gtk so I cannot help, but it would be nice if you could just disable doublebuffering for single widgets. Does any gtk expert know if this is possible?

gtk_widget_set_double_buffered(YourGtkWidgetHandle, False);

Luiz

Tank you Luiz!

I put that in GLLinGTKContext.pas at procedure
TGLGTKContext.DoCreateContext and no more flickering.

Patrick

Can you submit a patch?