/// <summary>
/// Creates a 4 x 4 matrix where all the values represent an identity matrix except
/// that the bottom row has been set to be the translation values. The result is
/// that if a 3D vector is transformed by this matrix, the last row will
/// control the translation terms.
/// </summary>
/// <param name="x">The translation in the x direction</param>
/// <param name="y">The translation in the y direction</param>
/// <param name="z">The translation in the z direction</param>
/// <returns>The translation matrix</returns>
public static Matrix4 Translation(double x, double y, double z)
{
Matrix4 result = new Matrix4();
double[,] vals = result.Values;
vals[3, 0] = x;
vals[3, 1] = y;
vals[3, 2] = z;
return result;
}
/// <summary>
/// Creates a 4 x 4 matrix that can be used to rotate a 3D vector about the Z axis.
/// </summary>
/// <param name="degrees">The counter-clockwise angle of rotation when looking at the origin from the positive axis</param>
/// <returns>A 4x4 rotation matrix</returns>
public static Matrix4 RotationZ(double degrees)
{
Matrix4 result = new Matrix4();
double rad = degrees * Math.PI / 180;
double[,] vals = result.Values;
vals[0, 0] = Math.Cos(rad);
vals[0, 1] = -Math.Sin(rad);
vals[1, 0] = Math.Sin(rad);
vals[1, 1] = Math.Cos(rad);
return result;
}