=head1 NAME

Box2D::b2DistanceJoint - Constrains two bodies at a fixed distance.

=head1 SYNOPSIS

  my $joint = $world->CreateJoint( $joint_def );
  my $anchor_a = $joint->GetAnchorA();
  my $anchor_b = $joint->GetAnchorB();

=head1 DESCRIPTION

A distance joint constrains two points on two bodies to remain at a
fixed distance from each other. You can view this as a massless, rigid
rod.

=head1 METHODS

=head2 GetAnchorA()

Get the anchor point on bodyA in world coordinates. Implements
C<Box2D::b2Joint>.

Returns a C<Box2D::b2Vec2>

=head2 GetAnchorB()

Get the anchor point on bodyB in world coordinates. Implements
C<Box2D::b2Joint>.

Returns a C<Box2D::b2Vec2>

=head2 GetDampingRatio()

Returns a C<float32>

=head2 GetFrequency()

Returns a C<float32>

=head2 GetLength()

Returns a C<float32>

=head2 GetReactionForce( $inv_dt )

Get the reaction force on body2 at the joint anchor in Newtons.
Implements C<Box2D::b2Joint>.

Parameters:

=over 4

=item * C<float32> C<$inv_dt>

=back

Returns a C<Box2D::b2Vec2>

=head2 GetReactionTorque( $inv_dt )

Get the reaction torque on body2 in N*m. Implements C<Box2D::b2Joint>.

Parameters:

=over 4

=item * C<float32> C<$inv_dt>

=back

Returns a C<float32>

=head2 SetDampingRatio( $ratio )

Parameters:

=over 4

=item * C<float32> C<$ratio>

=back

=head2 SetFrequency( $hz )

Parameters:

=over 4

=item * C<float32> C<$hz>

=back

=head2 SetLength( $length )

Set/get the natural length. Manipulating the length can lead to
non-physical behavior when the frequency is zero.

Parameters:

=over 4

=item * C<float32> C<$length>

=back

=head1 SEE ALSO

=over 4

=item * L<Box2D>

=item * L<Box2D::b2DistanceJointDef>

=item * L<Box2D::b2Joint>

=item * L<Box2D::b2World>

=back

=head1 BUGS

See L<Box2D/BUGS>

=head1 AUTHORS

See L<Box2D/AUTHORS>

=head1 COPYRIGHT & LICENSE

See L<Box2D/"COPYRIGHT & LICENSE">

=cut