百度地图api如何绘制曲线？

我刚学百度地图，我看了下，绘制工具里只有点 折线 圆 矩形 几何图形这几种覆盖物，曲线如何实现画出来

  var path=[ new BMapGL.Point(X, Y),new BMapGL.Point(X, Y),new BMapGL.Point(X, Y),new BMapGL.Point(X, Y)];
  var controlPoints=[[new BMapGL.Point(X, Y),new BMapGL.Point(X, Y)],[new BMapGL.Point(X, Y),new BMapGL.Point(X, Y)],[new BMapGL.Point(X, Y),new BMapGL.Point(X, Y)]];
  var bc = new BMapGL.BezierCurve(path, controlPoints, {
    strokeColor: '#008000'     
  });

map.addOverlay(bc);

我找了下，有个BezierCurve贝塞尔曲线，有点看不懂，我要画一条弯弯曲曲的曲线，他只是提供了一个二阶的贝塞尔曲线，画一条弯弯曲曲的曲线