Path: chuka.playstation.co.uk!news
From: "Jon Prestidge (Moose)" <jon@surfed.to>
Newsgroups: scee.yaroze.programming.3d_graphics
Subject: Re: Line normal
Date: Sat, 4 Mar 2000 12:23:57 -0000
Organization: PlayStation Net Yaroze (SCEE)
Lines: 26
Message-ID: <89qvbs$9g42@chuka.playstation.co.uk>
References: <38ac28a2.9170426@news.playstation.co.uk>
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A simple way is to just find dx and dy and swap them and use them to draw
the perpendicular line. Change the sign of dx or dy depending on which way
you want the perpendicular line to point.

dx is simply found by subtracting the x ordinate at the start of the line
from the x ordinate at the end of the line ... and find dy by doing the same
for the y ordinates.
Decide the co-ordinate where you want the new line to start then just add
the swapped dx and dy to x and y respectively to find the end point of the
new line.

Jon Prestidge


Rad <kr705@gre.ac.uk> wrote in message
news:38ac28a2.9170426@news.playstation.co.uk...
> Hi,
>
> If I have a line, how do I calculate another line perpendicular to
> this line?
> Or should that be how do I calculate the normal to a line?
>
> Thanks,
> Rad.