Math Help?

Scott Rossi scott at
Fri Apr 30 17:28:22 EDT 2010

Many thanks Malte and Jeff.  I now have a couple of good options to work
with.  I knew there must be some way to test this.

(I could not rely on Rev's built-in within()/intersection functions in this
case because I need to translate this behavior to another environment.)

Thanks & Regards,

Scott Rossi
Creative Director
Tactile Media, UX Design

Recently, Malte Pfaff-Brill wrote:

> function withinTriangle x1,y1,x2,y2,x3,y3,px,py
>    -- x1 / y1 to x3 / y3 define the triangle, pX and pY are the point to check
>    local area1,area2
>    put area(x1,y1,x2,y2,px,py) + area(x2,y2,x3,y3,px,py) +
> area(x3,y3,x1,y1,px,py) into area1
>    put area(x1,y1,x2,y2,x3,y3) into area2
>    return abs(area1-area2)<0.000000000001
> end withinTriangle
> function area x1,y1,x2,y2,x3,y3
>    return abs(x1*y2+x2*y3+x3*y1-x1*y3-x3*y2-x2*y1)/2
> end area

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