the gdk.GLContext with which to share display lists and texture objects. NULL indicates that no sharing is to take place.
whether rendering is to be done with a direct connection to the graphics system.
GDK_GL_RGBA_TYPE.
Return: the new gdk.GLContext
Creates a new gdk.GLContext with the appropriate GdkGLDrawable for this widget. The GL context must be freed when you're finished with it. See also Widget.getGlContext.