public void updateModelView(ref Matrix4 modelViewMatrix)
{
Quaternion quat = modelViewMatrix.ExtractRotation().Inverted();
Vector3 euler = OpenTKHelper.QuaternionToEuler(ref quat);
Vector3 baseVec = new Vector3(euler.X + 0.5f * (float)Math.PI, euler.Y, euler.Z);
orientationMin = baseVec + new Vector3((float)Math.PI / 8f, 0f, 0f);
orientationMax = baseVec + new Vector3((float)Math.PI * 3f / 8f, 2f * (float)Math.PI, 0f);
}
