Sorry? I'm not sure where your going with that. I've left out the conversions for ease of explanation. My problem is not related to them, and there would have been no value adding them to the post.
I have managed to get to this equation:
Code:
Y2 = X * Cos(t) - Y * Sin(t)
X2 = X * Sin(t) + Y * Cos(t)
It assumes your working in radians (decimal to radians conversion:
t = t * Pi / 180. It only appears to work with theta of 0,90,180,270,360 (increments of 90°).
Anyone able to spot where I'm going wrong here?