public int sign(Vector2D v2)
{
return prep.dotProd(v2) < 0 ? -1 : 1;
}
//两向量相减
public Vector2D subtract(Vector2D v2)
{
return new Vector2D(_x - v2.x, _y - v2.y);
}
//向量积
public double dotProd(Vector2D v2)
{
return _x * v2.x + _y * v2.y;
}
public Boolean equals(Vector2D v2)
{
return _x == v2.x && _y == v2.y;
}
//返回当前向量与V2的距离的平方
public double distanceSQ(Vector2D v2)
{
double dx = v2.x - _x;
double dy = v2.y - _y;
return dx * dx + dy * dy;
}
//返回当前向量与V2的距离
public double distance(Vector2D v2)
{
return Math.Sqrt(distanceSQ(v2));
}
//判断两向量是否垂直
public double crossProd(Vector2D v2)
{
return _x * v2.y - _y * v2.x;
}
//两向量相加
public Vector2D add(Vector2D v2)
{
return new Vector2D(_x + v2.x, _y + v2.y);
}
//返回两向量夹角的弧度值
public static double angleBetween(Vector2D v1, Vector2D v2)
{
if (!v1.isNormalized())
{
v1 = v1.clone().normalize();
}
if (!v2.isNormalized())
{
v2 = v2.clone().normalize();
}
return Math.Acos(v1.dotProd(v2));
}