/// <summary>
///
/// </summary>
/// <param name="v"></param>
/// <returns></returns>
public bool IsParallel(Vector2D v)
{
return 0d == RobustDeterminant.SignOfDet2x2(_x, _y, v._x, v._y);
}
/// <summary>
/// Creates a new vector instance based on <paramref name="v"/>.
/// </summary>
/// <param name="v">The vector</param>
public Vector2D(Vector2D v)
{
_x = v._x;
_y = v._y;
}
/// <summary>
///
/// </summary>
/// <param name="v"></param>
/// <returns></returns>
public double AngleTo(Vector2D v)
{
var a1 = Angle();
var a2 = v.Angle();
var angDel = a2 - a1;
// normalize, maintaining orientation
if (angDel <= -System.Math.PI)
return angDel + AngleUtility.PiTimes2;
if (angDel > System.Math.PI)
return angDel - AngleUtility.PiTimes2;
return angDel;
}
/// <summary>
/// Creates a new vector from an existing one.
/// </summary>
/// <param name="v">The vector to copy</param>
/// <returns>A new vector</returns>
public static Vector2D Create(Vector2D v)
{
return new Vector2D(v);
}
/// <summary>
/// Computes the dot-product of two vectors
/// </summary>
/// <param name="v">A vector</param>
/// <returns>The dot product of the vectors</returns>
public double Dot(Vector2D v)
{
return _x * v._x + _y * v._y;
}
/// <summary>
///
/// </summary>
/// <param name="v"></param>
/// <returns></returns>
public double Angle(Vector2D v)
{
return AngleUtility.Diff(v.Angle(), Angle());
}
/// <summary>
/// Computes the distance between this vector and another one.
/// </summary>
/// <param name="v">A vector</param>
/// <returns>The distance between the vectors</returns>
public double Distance(Vector2D v)
{
double delx = v._x - _x;
double dely = v._y - _y;
return System.Math.Sqrt(delx * delx + dely * dely);
}
/// <summary>
/// Computes the weighted sum of this vector
/// with another vector,
/// with this vector contributing a fraction
/// of <tt>frac</tt> to the total.
/// <para/>
/// In other words,
/// <pre>
/// sum = frac * this + (1 - frac) * v
/// </pre>
/// </summary>
/// <param name="v">The vector to sum</param>
/// <param name="frac">The fraction of the total contributed by this vector</param>
/// <returns>The weighted sum of the two vectors</returns>
public Vector2D WeightedSum(Vector2D v, double frac)
{
return Create(
frac * _x + (1.0 - frac) * v._x,
frac * _y + (1.0 - frac) * v._y);
}
/// <summary>
///
/// </summary>
/// <param name="v"></param>
/// <returns></returns>
public Vector2D Average(Vector2D v)
{
return WeightedSum(v, 0.5);
}
/// <summary>
/// Subtracts <paramref name="v"/> from this vector instance
/// </summary>
/// <param name="v">The vector to subtract</param>
/// <returns>The result vector</returns>
public Vector2D Subtract(Vector2D v)
{
return Create(_x - v._x, _y - v._y);
}
/// <summary>
/// Adds <paramref name="v"/> to this vector instance.
/// </summary>
/// <param name="v">The vector to add</param>
/// <returns>The result vector</returns>
public Vector2D Add(Vector2D v)
{
return Create(_x + v._x, _y + v._y);
}
