OpenEuphoria

Re: mathmatical question.. - Reply

• Posted by Lucius L Hilley III <luciuslhilleyiii at JUNO.COM> May 30, 1997
• 772 views

On Fri, 30 May 1997 11:23:34 +1200 "BABOR, JIRI" <J.Babor at GNS.CRI.NZ>
writes:
>---------------------- Information from the mail header
>
>Lee woo seob posed a mathematical problem (his words, not mine), he
>can do
>palette shuffling and/or pixel color detection well enough on his own
>- see his
>snow poem program on The Official Euphoria Page. He also emphasized
>"INSIDE the
>polygon" (his capitals, not mine!), and that is why my routine would
>not even
>detect your boundary (vertex) point. (Btw, *odd* count indicates the
>point *is* inside)
>And how is triangulation going to help anything? Pure magic? Jiri

not triangulaion.
Triangulation is finding a point by using three reference points.

I propose cutting the image into triangles because a triangle
is the fewest sided polygon. It can't a concave shape.
       ____
 /\   \    /
/__\  /____\

As this image shows even a 4 sided figure can have a concave
shape giving the possibility of an inaccurate COUNT.
and BTW My thought of going in opposite directions doesn't
work either for the same reason your count won't.

 ____
|    |  the dot is where the click was made.
|    |
| /\.|
|/  \|
  ____
 |    |  this line gives a count of 4.
 |    |
_|_/\_|_
 |/  \|


 ____
|    |  the dot is where the click was made.
|   .|
| /\ |
|/  \|
  ____
 |    |
_|____|_  this line gives a count of 3.
 | /\ |   BOTH clicks are inside.
 |/  \|