GtkGLExt is an OpenGL extension to GTK+. It provides additional GDK objects which support OpenGL rendering in GTK+ and GtkWidget API add-ons to make GTK+ widgets OpenGL-capable. In contrast to Janne Löf's GtkGLArea, GtkGLExt provides a GtkWidget API that enables OpenGL drawing for standard and custom GTK+ widgets. Like GTK+ itself, GtkGLExt is licensed under the GNU LGPL 2.1.