Re: Algorithm to find the shortest rotation using degrees?

> I think you haven't taken a close look at the atan function.  I don't
> believe it's returning what you think it is.  Something like the
following
> is more useful:
>
> double CalcTheta( const JVEC2 Point1, const JVEC2 Point2 )
> {
>     double Theta = atan2( (Point2.x - Point1.x), (Point2.y - Point1.y) 
);
>     if ( Theta < 0 )
>         return 2 * PI + Theta;
>     else
>         return Theta;
> }
>
> First atan2 simplies it a little in that it takes two points so you
don't
> have to do the devisor.  It also handles the case if deltaX is 0 (in
your
> case would be devide by zero error).

Thanks Jim- based on your recommendation I came up with the following:

inline int shortestDirec(double start, double target)
{
	if(start < target)
	{
		if( (target - start) < (360 - target + start) )
			return 1;//turn left
		else
			return -1;//turn right
	}
	if(start > target)
	{
		if( (start - target) < (360 - start + target) )
			return -1;//turn right
		else
			return 1;//turn left
	}
	else
		return 0; // exactly aligned
}

am I overkilling with the two scenarios?

Thanks again
Scott