Draw polygon from array of points

How to draw a filled polygon, non convex polygon if I have array of points ? I am drawing Rectangle as ( in OnRenderObject function ):

             GL.PushMatrix ();
             // Set transformation matrix for drawing to
             // match our transform
             GL.MultMatrix (transform.localToWorldMatrix);


             GL.Begin (GL.QUADS);
             GL.Color (new Color (0.0f, 0.2f, 0.0f, 0.4F));
             GL.Vertex3 (0, 0, 0);
             GL.Vertex3 (0, 0, 1);
             GL.Vertex3 (1, 0, 1);
             GL.Vertex3 (1, 0, 0);
     
             GL.Color (new Color (0.7f, 0.2f, 0, 0.8F));
             GL.Vertex3 (1, 0, 1);
             GL.Vertex3 (1, 0, 2);
             GL.Vertex3 (2, 0, 2);
             GL.Vertex3 (2, 0, 1);

             GL.End ();
             GL.PopMatrix ();

But how to draw a filled polygon with some color ? ( I managed to draw by doing triangulation of polygon and then draw GL.TRIANGLES but I wonder is there better and quicker solution).