how do i find out if a parametric function is turning left or right?
test your algorithm on these functions:

t goes from 0->360 degrees or 0->2pi radians
x=sin(t)
y=cos(t)
should always turn right.


t goes from 0->360 degrees or 0->2pi radians
x=sin(t)
y=cos(2t)
turns right from t=0 to t=pi
turns left from t=pi to t=2pi

thanks.

-marvin