public static MathPoint Project(this IMathPoint point, IMathPoint origin, IMathVector axis)
{
var a = (IMathVector) point.Subtract(origin);
var t = a.Project(axis);
var v = (MathVector) axis.Scale(t);
return (MathPoint) origin.AddVector(v);
}
/// <summary>
/// 计算在某轴上的投影
/// </summary>
/// <param name="point"></param>
/// <param name="origin"></param>
/// <param name="axis"></param>
/// <returns></returns>
public static MathPoint Project(this IMathPoint point, IMathPoint origin, IMathVector axis)
{
var a = (IMathVector)point.Subtract(origin);
var t = a.Project(axis);
var v = (MathVector)axis.Scale(t);
return((MathPoint)origin.AddVector(v));
}
public static IMathPoint MoveAlongVector(this IMathPoint pt, IMathVector dir, double dist)
{
dir = dir.Normalise().Scale(dist) as IMathVector;
var centerPt = pt.AddVector(dir) as IMathPoint;
return(centerPt);
}
public static MathPoint AddTs(this IMathPoint a, IMathVector b)
{
return((MathPoint)a.AddVector(b));
}
