# File gtkglext/sample/simple-mixed.rb, line 39
def realize(w)
    glcontext = w.gl_context
    gldrawable = w.gl_drawable

    gldrawable.gl_begin(glcontext) do
        qobj = GLU.NewQuadric
        GLU.QuadricDrawStyle(qobj, GLU::FILL)
        GL.NewList(1, GL::COMPILE)
        GLU.Sphere(qobj, 1.0, 20, 20)
        GL.EndList

        GL.Light(GL::LIGHT0, GL::DIFFUSE, LIGHT_DIFFUSE)
        GL.Light(GL::LIGHT0, GL::POSITION, LIGHT_POSITION)
        GL.Enable(GL::LIGHTING)
        GL.Enable(GL::LIGHT0)
        GL.Enable(GL::DEPTH_TEST)

        GL.ClearColor(1.0, 1.0, 1.0, 1.0)
        GL.ClearDepth(1.0)

        GL.Viewport(0, 0, w.allocation.width, w.allocation.height)

        GL.MatrixMode(GL::PROJECTION)
        GL.LoadIdentity
        GLU.Perspective(40.0, 1.0, 1.0, 10.0)

        GL.MatrixMode(GL::MODELVIEW)
        GL.LoadIdentity
        GLU.LookAt(0.0, 0.0, 3.0,
                   0.0, 0.0, 0.0,
                   0.0, 1.0, 0.0)
        GL.Translate(0.0, 0.0, -3.0)
    end
end