Elysian Shadows

GyroVorbis wrote: The angle between the two is simply the inverse cosine of the X component of our normalized vector. That's one additional trig function.

Shouldn't you check if the y component is negative and add pi radians if it is?

I guess this method could also be described by just using the unit circle and not event talk about dot products, for this specific case (which i guess is not uncommon) where you want to find the angle between a vector and the x axis.