# Filename : Math/Geometry.pm
# Description : General Geometry maths functions
# Author : Greg McCarroll (greg@mccarroll.demon.co.uk)
# Date Created : 22/10/99
Math::Geometry - Geometry related functions
@N =triangle_normal(@P1,@P2,@P3);
@ZP=zplane_project(@P1,$d);
This is about to get a massive overhaul, but first im adding tests,
lots of lovely lovely tests.
Currently for zplane_project onto a plane with normal of the z axis and z=0,
the function returns the orthographic projections as opposed to a perspective
projection. I'm currently looking into how to properly handle z=0 and will
This package implements classic geometry methods. It should be considered alpha
software and any feedback at all is greatly appreciated. The following methods
Also known as the cross product, given two vectors in Geometry space, the
vector_product of the two vectors, is a vector which is perpendicular
to the plane of AB with length equal to the length of A multiplied
by the length of B, multiplied by the sin of @, where @ is the angle
Given a triangle ABC that defines a plane P. This function will return
a vector N, which is a normal to the plane P.
triangle_normal(($Ax,$Ay,$Az),($Bx,$By,$Bz),($Cx,$Cy,$Cz));
Project a point in Geometry space onto a plane with the z-axis as the normal,
at a distance d from z=0.
($x2,$y2,$z2) = zplane_project ($x1,$y1,$z1,$d);
Rotate about the x axis r radians.
($x2,$y2,$z2) = rotx ($x1,$y1,$z1,$r);
Rotate about the y axis r radians.
($x2,$y2,$z2) = roty ($x1,$y1,$z1,$r);
Rotate about the z axis r radians.
($x2,$y2,$z2) = rotz ($x1,$y1,$z1,$r);
Convert degree's to radians.
Convert radians to degree's.
Returns an approximate value of Pi, the code has been cribed from Pg146, Programming Perl
Greg McCarroll <greg@mccarroll.demon.co.uk>
@EXPORT = qw
/zplane_project triangle_normal rotx roty rotz rad2deg deg2rad pi/;
return "Math::Geometry $VERSION";
my($a,$b,$c,$d,$e,$f)=@_;
return($b*$f-$c*$e,$c*$d-$a*$f,$a*$e-$b*$d);
my(($ax,$ay,$az),($bx,$by,$bz),($cx,$cy,$cz))=@_;
my(@AB)=($bx-$ax,$by-$ay,$bz-$az);
my(@AC)=($cx-$ax,$cy-$ay,$cz-$az);
return(vector_product
(@AB,@AC));
my($trans)=new Math
::Matrix
([ 1, 0, 0, 0],
my($orig) =new Math
::Matrix
([ $x],
my($prod) =$trans->multiply($orig);
my($trans)=new Math
::Matrix
([ 1, 0, 0, 0],
my($orig) =new Math
::Matrix
([ $x],
my($prod) =$trans->multiply($orig);
my($trans)=new Math
::Matrix
([ 1, 0, 0, 0],
my($orig) =new Math
::Matrix
([ $x],
my($prod) =$trans->multiply($orig);
my($trans)=new Math
::Matrix
([ $cosr, 0, $sinr, 0],
my($orig) =new Math
::Matrix
([ $x],
my($prod) =$trans->multiply($orig);
my($trans)=new Math
::Matrix
([ $cosr,-1*$sinr, 0, 0],
my($orig) =new Math
::Matrix
([ $x],
my($prod) =$trans->multiply($orig);