Beefy Boxes and Bandwidth Generously Provided by pair Networks
Syntactic Confectionery Delight

Re: Check if line is straight

by pajout (Curate)
on May 16, 2011 at 06:36 UTC ( #905021=note: print w/ replies, xml ) Need Help??

in reply to Check if line is straight

If you really want to check colinearity of three points, you can just multiply vectors:

sub isCorrectPath () { my ($x1, $y1, $x2, $y2, $x, $y) = @_; return !(($x2-$x1)*($y-$y1)-($x-$x1)*($y2-$y1)); }

Comment on Re: Check if line is straight
Download Code
Replies are listed 'Best First'.
Re^2: Check if line is straight
by Anonymous Monk on May 16, 2011 at 20:14 UTC
    This is pretty neat, saves a lot of code. What is the best way to add tolerance to this? any suggestions ? Thanks
      return abs(($x2-$x1)*($y-$y1)-($x-$x1)*($y2-$y1)) < $tolerance;

      Update added abs()

      It depends if you mean tolerance necessary for dealing floats - lidden suggested it already. But if you mean real tolerance, for instance "path is correct if the angle between two vectors is less than 1 degree", you should really compute that value.

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://905021]
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others chanting in the Monastery: (10)
As of 2015-10-13 07:16 GMT
Find Nodes?
    Voting Booth?

    Does Humor Belong in Programming?

    Results (296 votes), past polls