// if view is straight up or down, this will be a null vector (NaN after normalization)
// in that case maybe the model forward should be used?
// the current implementation implicitly falls back to TURN_NONE which is -Z
// if view is straight up or down, this will be a null vector (NaN after normalization)
// in that case maybe the model forward should be used?
// the current implementation implicitly falls back to TURN_NONE which is -Z