由网友(海阔山遥)分享简介：予有2点的坐标（x，y）的。我想建立的第三点，使这3点做出一个等边三角形。 I have the coordinates (x,y) of 2 points. I want to build the third point so that these 3 points make an equilateral tria...

予有2点的坐标（x，y）的。我想建立的第三点，使这3点做出一个等边三角形。

I have the coordinates (x,y) of 2 points. I want to build the third point so that these 3 points make an equilateral triangle.

我如何计算第三点？

感谢您

推荐答案

看完帖子后（特别是vkit的），我公司生产的这一段简单的code这会做的伎俩一个方向（记住，有两个点）。该修改的其他情况shold是微不足道的。

After reading the posts (specially vkit's) I produced this simple piece of code which will do the trick for one direction (remember that there are two points). The modification for the other case shold be trivial.

#include<stdio.h>
#include<math.h>

typedef struct{
  double x;
  double y;
} Point;

Point vertex(Point p1, Point p2){
  double s60 = sin(60 * M_PI / 180.0);    
  double c60 = cos(60 * M_PI / 180.0);

  Point v = {
    c60 * (p1.x - p2.x) - s60 * (p1.y - p2.y) + p2.x,
    s60 * (p1.x - p2.x) + c60 * (p1.y - p2.y) + p2.y
  };

  return v;
}