Primitives
----------

Primal includes the following primitives:

- Point
- Segment, Ray, Vector
- Plane, Triangle, Polygon
- Quadrilateral
- Sphere
- Tetrahedron
- Hexahedron
- BoundingBox, OrientedBoundingBox
- Polyhedron

.. note:: Primitives in Axom use a right-handed coordinate system.

Primal also provides the NumericArray class, which implements arithmetic
operations on numerical tuples and supports Primal's Point and Vector classes.
Classes in Primal are templated on coordinate type (double, float, etc.) and
dimension.  The primitives do not inherit from a common base class.  This was a
design choice in favor of simplicity and performance.  Geometric primitives can
be tested for equality and can be printed to strings.

Primal also includes functions to merge a pair of BoundingBox or a pair of 
OrientedBoundingBox objects and to create new OrientedBoundingBox objects 
from a list of points.

The following includes header files for primal's primitives
as well as some ``using`` directives and ``typedef`` statements that will be used in
the examples. Header files for operations will be shown next to code examples.
Although the examples ``#include`` separate class header files, it is easier and
less error-prone to write ``#include axom/primal.hpp``.

.. literalinclude:: ../../examples/primal_introduction.cpp
   :start-after: _prims_header_start
   :end-before: _prims_header_end
   :language: C++

.. literalinclude:: ../../examples/primal_introduction.cpp
   :start-after: _using_start
   :end-before: _using_end
   :language: C++