Unity 平面点到直线的距离

public static float disPoint2Line(Vector2 point1, Vector2 point2, Vector2 position)//point1和point2为线的两个端点
{
float accuracy = 0.01f;
float distance = 0;
float a = Vector2.Distance(point1,point2);// 线段的长度
float b = Vector2.Distance(position, point1);// position到点point1的距离
float c = Vector2.Distance(position, point2);// position到point2点的距离
if (c <= accuracy || b <= accuracy)
{
distance = 0;
return distance;
}
if (a <= accuracy)
{
distance = b;
return distance;
}
if (c * c >= a * a + b * b)
{
distance = b;
return distance;
}
if (b * b >= a * a + c * c)
{
distance = c;
return distance;
}
float p = (a + b + c) / 2;// 半周长
float s = Mathf.Sqrt(p * (p - a) * (p - b) * (p - c));// 海伦公式求面积
distance = 2 * s / a;// 返回点到线的距离（利用三角形面积公式求高）
return distance;
}