On Fri, Apr 30, 2010 at 3:43 PM, Scott Rossi <[email protected]> wrote:
> > Dot products... normalized vectors... head starting to spin... vision > getting blurry... > Hehe. ;-) > > OK, Jeff, so does (B-A).x mean the x coordinate of point B minus the x > coordinate of point A? > > Yes. This might help: freespace.virgin.net/hugo.elias/routines/r_dot.htm 2D dot product: dot(p1,p2) = (p1.x * p2.x) + (p1.y * p2.y) In this case, since you are dealing with line segments, the segment AB would mean that: p1.x = B.x - A.x p1.y = B.y - A.y Expanding this out... dot(AB, AD) = [(B.x-A.x) * (D.x-A.x)] + [(B.y-A.y) * (D.y-A.y)] Hope that helps! Jeff M. _______________________________________________ use-revolution mailing list [email protected] Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
