public void RotateY(double radians)
{
Matrix3 m = new Matrix3();
m.SetRotateY(radians);
Set(this * m);
}
public void SetEuler(float pitch, float yaw, float roll)
{
Matrix3 x = new Matrix3();
Matrix3 y = new Matrix3();
Matrix3 z = new Matrix3();
x.SetRotateX(pitch);
y.SetRotateY(yaw);
z.SetRotateZ(roll);
// combine rotations in a specific order
Set(z * y * x);
}