BezierCurve

代码说明：

说明：  Bezier曲线的绘制，多项式系数的值由函数GetCnk计算，沿曲线路径的坐标位置由函数GetPointPr计算，最后由BezierCurve函数通过OpenGL画点功能实现曲线绘制。这里绘制的是一个包含4个控制点的三次Bezier曲线。(In Bezier curve drawing, the value of polynomial coefficients is calculated by function GetCnk, the coordinate position along the curve path is calculated by function GetPointPr, and finally the curve is drawn by Bezier Curve function through OpenGL point drawing function. Here we draw a cubic Bezier curve with four control points.)