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lib/Math/Zap/Rectangle.pm  view on Meta::CPAN

=head2 Constructors


=head3 new

Create a rectangle from 3 vectors:

 a position of any corner
 b first side
 c second side.

Note that vectors b,c must be at right angles to each other.

=cut


sub new($$$)
 {my ($a, $b, $c) = vectorCheck(@_);
  $b->dot($c) == 0 or confess 'non rectangular rectangle specified';
  bless {a=>$a, b=>$b, c=>$c}; 
 }


=head3 rectangle

Create a rectangle from 3 vectors - synonym for L</new>.

=cut


sub rectangle($$$) {new($_[0],$_[1],$_[2])};


=head2 Methods


=head3 check

Check its a rectangle

=cut


sub check(@)
 {for my $r(@_)
   {confess "$r is not a rectangle" unless ref($r) eq __PACKAGE__;
   }
  return (@_)
 }


=head3 is

Test its a rectangle

=cut


sub is(@)
 {for my $r(@_)
   {return 0 unless ref($r) eq __PACKAGE__;
   }
  'rectangle';
 }


=head3 a,b,c

Components of rectangle

=cut


sub a($) {my ($r) = check(@_); $r->{a}}
sub b($) {my ($r) = check(@_); $r->{b}}
sub c($) {my ($r) = check(@_); $r->{c}}


=head3 clone

Create a rectangle from another rectangle

=cut


sub clone($)
 {my ($r) = check(@_); # Rectangles
  bless {a=>$r->a, b=>$r->b, c=>$r->c};
 }


=head3 accuracy

Get/Set accuracy for comparisons

=cut


my $accuracy = 1e-10;

sub accuracy
 {return $accuracy unless scalar(@_);
  $accuracy = shift();
 }


=head3 intersection

Intersect line between two vectors with plane defined by a rectangle

 r rectangle
 a start vector
 b end vector

Solve the simultaneous equations of the plane defined by the
rectangle and the line between the vectors:

   ra+l*rb+m*rc         = a+(b-a)*n 
 =>ra+l*rb+m*rc+n*(a-b) = a-ra