=head1 NAME

Box2D::b2Transform - Contains translation and rotation.

=head1 SYNOPSIS

  my $transform = Box2D::b2Transform->new( $postiion, $rotation );

=head1 DESCRIPTION

A transform contains translation and rotation. It is used to represent
the position and orientation of rigid frames.

=head1 METHODS

=head2 new( $position, $R )

Initialize using a position vector and a rotation matrix.

Parameters:

=over 4

=item * C<Box2D::b2Vec2> C<$position>

=item * C<Box2D::b2Mat22> C<$R>

=back

Returns a C<Box2D::b2Transform>

=head2 GetAngle()

Calculate the angle that the rotation matrix represents.

Returns a C<float32>

=head2 Set( $p, $angle )

Set this based on the position and angle.

Parameters:

=over 4

=item * C<Box2D::b2Vec2> C<$p>

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

=back

=head2 SetIdentity()

Set this to the identity transform.

=head2 position()

=head2 position( $position )

Parameters:

=over 4

=item * C<Box2D::b2Vec2> C<$position> (optional)

=back

Returns a C<Box2D::b2Vec2>

=head2 R()

=head2 R( $rotation )

Parameters:

=over 4

=item * C<Box2D::b2Mat22> C<$rotation> (optional) - rotation matrix

=back

Returns a C<Box2D::b2Mat22>

=head1 SEE ALSO

=over 4

=item * L<Box2D>

=item * L<Box2D::b2Mat22>

=back

=head1 BUGS

See L<Box2D/BUGS>

=head1 AUTHORS

See L<Box2D/AUTHORS>

=head1 COPYRIGHT & LICENSE

See L<Box2D/"COPYRIGHT & LICENSE">

=cut