ops me l'ero dimenticata:
codice:
# returns vector cross product of vectors p1p2 and p1p3
# using Cramer's rule
#
# args : reference to an array with 3 points p1,p2 and p3
#
sub CrossProduct {
my $pointsref = $_[0];
my @points = @$pointsref;
if (@points != 3) {
carp("Need 3 points for a cross product");
return;
}
my @p1 = @{$points[0]}; <-linea 367
my @p2 = @{$points[1]};
my @p3 = @{$points[2]};
my $det_p2p3 = &Determinant($p2[0], $p2[1], $p3[0], $p3[1]);
my $det_p1p3 = &Determinant($p1[0], $p1[1], $p3[0], $p3[1]);
my $det_p1p2 = &Determinant($p1[0], $p1[1], $p2[0], $p2[1]);
return ($det_p2p3-$det_p1p3+$det_p1p2);
}