/// <summary>
/// Returns the normal for the triangle. (Costly method!)
/// </summary>
/// <remarks>
/// <para>
/// The normal of a triangle is the vector perpendicular to the triangle's plane
/// with the direction determined by the
/// <a href="http://en.wikipedia.org/wiki/Right-hand_rule" target="_blank">
/// right-handed rule</a>.
/// </para>
/// </remarks>
/// <param name="a">Vertex A of triangle ABC.</param>
/// <param name="b">Vertex B of triangle ABC.</param>
/// <param name="c">Vertex C of triangle ABC.</param>
/// <returns>The normal of the triangle.</returns>
public static Vector3 GetNormal(Vector3 a, Vector3 b, Vector3 c)
{
// Reference:
// http://en.wikipedia.org/wiki/Surface_normal#Calculating_a_surface_normal
// N = (B - A) x (C - A) with the final result normalized.
return(Vector3Util.Normalize(Vector3Util.Cross(b - a, c - a)));
}