1. 用鼠标拖动输入的点做为控制顶点，生成一条B-样条曲线，显示控制顶点和多边形。用鼠标Pick曲线上任意一点，移动鼠标到新位置改变曲线形状。 2. 用鼠标输入一组数据点，插值生成一条B-样条曲线-1 with the mouse to drag the input points as control vertices to generate a B-spline curves, showing the control points and polygons. Pick the curve