static void AddQuad( VertexBuffer self, Rect rect )

static void AddQuad( VertexBuffer self, Vertex a, Vertex b, Vertex c, Vertex d )

static void AddQuad( VertexBuffer self, Vector3 a, Vector3 b, Vector3 c, Vector3 d )

static void AddQuad( VertexBuffer self, Ray origin, Vector3 width, Vector3 height )