contains_alignedbox_alignedbox.hpp

#ifndef PASTELGEOMETRY_CONTAINS_ALIGNEDBOX_ALIGNEDBOX_HPP
#define PASTELGEOMETRY_CONTAINS_ALIGNEDBOX_ALIGNEDBOX_HPP

#include "pastel/geometry/containment/contains_alignedbox_alignedbox.h"

#include "pastel/sys/vector/vector_tools.h"

namespace Pastel
{

    template <typename Real, integer N>
    bool contains(
        const AlignedBox<Real, N>& outer,
        const AlignedBox<Real, N>& inner)
    {
        PENSURE_OP(outer.n(), ==, inner.n());

        integer n = outer.n();
        for (integer i = 0;i < n;++i)
        {
            // forall i in [0, i[:

            // !inner.empty(i) && !outer.empty(i)

            if (inner.empty(i))
            {
                // The empty box is contained in every box.
                return true;
            }

            if (outer.empty(i))
            {
                // The outer box is empty.

                for (integer j = i + 1;j < n;++j)
                {
                    if (inner.empty(j))
                    {
                        // The empty box is contained in
                        // an empty box.
                        return true;
                    }
                }

                // Since the inner box is not empty
                // but the outer box is, there can't 
                // be containment.
                return false;
            }

            if (!containsPositiveHalfspace(
                outer.min()[i], outer.minTopology()[i],
                inner.min()[i], inner.minTopology()[i]))
            {
                // The inner box extends outside the 
                // minimum of the outer box.
                return false;
            }

            if (!containsNegativeHalfspace(
                outer.max()[i], outer.maxTopology()[i],
                inner.max()[i], inner.maxTopology()[i]))
            {
                // The inner box extends outside the 
                // maximum of the outer box.
                return false;
            }
        }

        // The inner box is contained in the outer box.
        return true;
    }

}

#endif