Manipulate 2D vectors
PhilipRBrenan@yahoo.com, 2004, Perl License
Example t/vector2.t
#_ Vector _____________________________________________________________ # Test 2d vectors # philiprbrenan@yahoo.com, 2004, Perl License #______________________________________________________________________ use Math::Zap::Vector2 vector2=>v, units=>u; use Test::Simple tests=>7; my ($x, $y) = u(); ok(!$x == 1); ok(2*$x+3*$y == v( 2, 3)); ok(-$x-$y == v(-1, -1)); ok((2*$x+3*$y) + (-$x-$y) == v( 1, 2)); ok((2*$x+3*$y) * (-$x-$y) == -5); ok($x*2 == v( 2, 0)); ok($y/2 == v( 0, 0.5));
Manipulate 2D vectors
package Math::Zap::Vector2; $VERSION=1.03; use Math::Trig; use Carp; use constant debug => 0; # Debugging level
Create a vector from numbers
sub new($$)
{return bless {x=>$_[0], y=>$_[1]} unless debug;
my ($x, $y) = @_;
round(bless({x=>$x, y=>$y}));
}
Create a vector from numbers - synonym for new
sub vector2($$) {new($_[0],$_[1])}
Unit vectors
$x = new(1,0);
$y = new(0,1);
sub units() {($x, $y)}
Check its a vector
sub check(@)
{if (debug)
{for my $v(@_)
{confess "$v is not a vector2" unless ref($v) eq __PACKAGE__;
}
}
return (@_)
}
Test its a vector
sub is(@)
{for my $v(@_)
{return 0 unless ref($v) eq __PACKAGE__;
}
1;
}
Get/Set accuracy for comparisons
my $accuracy = 1e-10;
sub accuracy
{return $accuracy unless scalar(@_);
$accuracy = shift();
}
Round: round to nearest integer if within accuracy of that integer
sub round($)
{unless (debug)
{return $_[0];
}
else
{my ($a) = @_;
for my $k(keys(%$a))
{my $n = $a->{$k};
my $N = int($n);
$a->{$k} = $N if abs($n-$N) < $accuracy;
}
return $a;
}
}
x,y components of vector
sub x($) {check(@_) if debug; $_[0]->{x}}
sub y($) {check(@_) if debug; $_[0]->{y}}
Create a vector from another vector
sub clone($)
{my ($v) = check(@_); # Vectors
round bless {x=>$v->x, y=>$v->y};
}
Length of a vector
sub length($)
{check(@_[0..0]) if debug; # Vectors
sqrt($_[0]->{x}**2+$_[0]->{y}**2);
}
Print vector
sub print($)
{my ($v) = check(@_); # Vectors
my ($x, $y) = ($v->x, $v->y);
"vector2($x, $y)";
}
Normalize vector
sub norm($)
{my ($v) = check(@_); # Vectors
my $l = $v->length;
$l > 0 or confess "Cannot normalize zero length vector $v";
new($v->x / $l, $v->y / $l);
}
At right angles
sub rightAngle($)
{my ($v) = check(@_); # Vectors
new(-$v->y, $v->x);
}
Dot product
sub dot($$)
{my ($a, $b) = check(@_); # Vectors
$a->x*$b->x+$a->y*$b->y;
}
Angle between two vectors
sub angle($$)
{my ($a, $b) = check(@_); # Vectors
acos($a->norm->dot($b->norm));
}
Add vectors
sub add($$)
{my ($a, $b) = check(@_); # Vectors
new($a->x+$b->x, $a->y+$b->y);
}
Subtract vectors
sub subtract($$)
{check(@_) if debug; # Vectors
new($_[0]->{x}-$_[1]->{x}, $_[0]->{y}-$_[1]->{y});
}
Vector times a scalar
sub multiply($$)
{my ($a) = check(@_[0..0]); # Vector
my ($b) = @_[1..1]; # Scalar
confess "$b is not a scalar" if ref($b);
new($a->x*$b, $a->y*$b);
}
Vector divided by a non zero scalar
sub divide($$)
{my ($a) = check(@_[0..0]); # Vector
my ($b) = @_[1..1]; # Scalar
confess "$b is not a scalar" if ref($b);
confess "$b is zero" if $b == 0;
new($a->x/$b, $a->y/$b);
}
Equals to within accuracy
sub equals($$)
{my ($a, $b) = check(@_); # Vectors
abs($a->x-$b->x) < $accuracy and
abs($a->y-$b->y) < $accuracy;
}
# Operator overloads
use overload '+' => \&add3, # Add two vectors '-' => \&subtract3, # Subtract one vector from another '*' => \&multiply3, # Times by a scalar, or vector dot product '/' => \÷3, # Divide by a scalar '<' => \&angle3, # Angle in radians between two vectors '>' => \&angle3, # Angle in radians between two vectors '==' => \&equals3, # Equals '""' => \&print3, # Print '!' => \&length, # Length 'fallback' => FALSE;
Add operator.
sub add3
{my ($a, $b) = @_;
$a->add($b);
}
Subtract operator.
sub subtract3
{#my ($a, $b, $c) = @_;
#return $a->subtract($b) if ref($b);
return new($_[0]->{x}-$_[1]->{x}, $_[0]->{y}-$_[1]->{y}) if ref($_[1]);
new(-$_[0]->{x}, -$_[0]->{y});
}
Multiply operator.
sub multiply3
{my ($a, $b) = @_;
return $a->dot ($b) if ref($b);
return $a->multiply($b);
}
Divide operator.
sub divide3
{my ($a, $b, $c) = @_;
return $a->divide($b);
}
Angle between two vectors.
sub angle3
{my ($a, $b, $c) = @_;
return $a->angle($b);
}
Equals operator.
sub equals3
{my ($a, $b, $c) = @_;
return $a->equals($b);
}
Print a vector.
sub print3
{my ($a) = @_;
return $a->print;
}
Export vector2, units, check, is
use Math::Zap::Exports qw( vector2 ($$) units () check (@) is (@) ); #_ Vector2 ____________________________________________________________ # Package loaded successfully #______________________________________________________________________ 1;
Perl License.