求两圆交点算法代码实现(Golang/Go语言)

package main

import (
"math"
)

//代表一个点，包含横纵坐标
type Point struct {
X, Y float64
}

//代表一个圆，包含横纵坐标及半径
type Circle struct {
Point
R float64
}

//创建圆对象
func NewCircle(x, y, r float64) *Circle {
return &Circle{Point{x, y}, r}
}

//求两圆相交的交点，交点个数可能有0,1,2
func Intersect(a *Circle, b *Circle) (p []Point) {
dx, dy := b.X - a.X, b.Y - a.Y
lr := a.R + b.R //半径和
dr := math.Abs(a.R - b.R) //半径差
ab := math.Sqrt(dx * dx + dy * dy) //圆心距
if ab <= lr && ab > dr {
theta1 := math.Atan(dy / dx)
ef := lr - ab
ao := a.R - ef / 2
theta2 := math.Acos(ao / a.R)
theta := theta1 + theta2
xc := a.X + a.R * math.Cos(theta)
yc := a.Y + a.R * math.Sin(theta)
p = append(p, Point{xc, yc})
if ab < lr { //两个交点
theta3 := math.Acos(ao / a.R)
theta = theta3 - theta1
xd := a.X + a.R * math.Cos(theta)
yd := a.Y - a.R * math.Sin(theta)
p = append(p, Point{xd, yd})
}
}
return
}