Polygonflow: clockwise or counter-clockwise?
massung at gmail.com
Wed Feb 3 09:47:52 EST 2010
I assume you are talking about 2D polygons...
Just take a 3D cross product of the first two vector (P3 - P2) x (P2 - P1).
If the resultant vector is coming out of the screen (Z < 0) then the polygon
is counter-clockwise. If it is going into the screen (Z > 0) then the
polygon is clockwise.
That page may be of help if you don't know what the cross product is. Note:
to do the 3D cross product, just use Z=0 for all the points.
On Wed, Feb 3, 2010 at 3:03 AM, Michael Kristensen <
michael-kristensen at dsa-net.dk> wrote:
> HI THERE
> Can you figure a smart way to check if the flow of a polygon goes clockwise
> or counter-clockwise?
> use-revolution mailing list
> use-revolution at lists.runrev.com
> Please visit this url to subscribe, unsubscribe and manage your
> subscription preferences:
More information about the Use-livecode