/// <summary>
/// Z軸(001)を引数のベクトルvに回転させる行列を生成する
/// </summary>
/// <param name="v"></param>
/// <returns></returns>
public static M3d CreateRotationFromZ(V3d v)
{
v.Normalize();
if (Math.Abs(v.Z - 1) < Th)
{
return(M3d.Identity);
}
else if (Math.Abs(v.Z + 1) < Th)
{
return(M3d.CreateRotationX(Math.PI));
}
else
{
return(M3d.CreateFromAxisAngle(V3d.Cross(v, Z), V3d.CalculateAngle(Z, v)));
}
}
/// <summary>
/// Z軸(001)を引数のベクトルvに回転させる行列を生成する
/// </summary>
/// <param name="v"></param>
/// <returns></returns>
public static M3d CreateRotationToZ(V3d v)
{
M3d rot;
v.Normalize();
if (Math.Abs(v.Z - 1) < Th)
{
rot = M3d.Identity;
}
else if (Math.Abs(v.Z + 1) < Th)
{
rot = M3d.CreateRotationX(Math.PI);
}
else
{
rot = M3d.CreateFromAxisAngle(V3d.Cross(Z, v), V3d.CalculateAngle(Z, v));
}
return(rot);
}