/// <summary>
/// Make a random unit vector.
/// </summary>
/// <remarks>
/// Samples points in [-1, -1, -1] - [1, 1, 1] until one that's neither at
/// the origin or outside the unit sphere is found. Returns this vector
/// normalized to unit length.
/// </remarks>
public Vec3 UnitVec()
{
double len;
Vec3 result;
do
{
result = new Vec3(
RandDouble(-1.0, 1.0),
RandDouble(-1.0, 1.0),
RandDouble(-1.0, 1.0));
len = result.Abs();
} while (len < Num.Epsilon || len > 1.0);
return result.Unit();
}
/// <summary>
/// The smallest angle in radians between two vectors.
/// </summary>
public static double Angle(Vec3 lhs, Vec3 rhs)
{
return Math.Acos(Dot(lhs.Unit(), rhs.Unit()));
}
