halfmesh_find.hpp

// Description: Searches for certain half-edges.

#ifndef PASTELGEOMETRY_HALFMESH_FIND_HPP
#define PASTELGEOMETRY_HALFMESH_FIND_HPP

#include "pastel/geometry/halfmesh/halfmesh.h"

namespace Pastel
{

    template <
        typename Settings, 
        template <typename> class Customization>
    auto HalfMesh<Settings, Customization>::findHalf(
        const Vertex_ConstIterator& from, 
        const Vertex_ConstIterator& to) const
        -> Half_ConstIterator
    {
        PENSURE(!from.empty());
        PENSURE(!to.empty());

        if (from->isolated() || to->isolated())
        {
            return Half_ConstIterator();
        }

        Half_ConstIterator begin = from->half();
        Half_ConstIterator current = begin;

        do
        {
            if (current->destination() == to)
            {
                return current;
            }

            current = current->rotateNext();
        }
        while (current != begin);

        return Half_ConstIterator();
    }

    template <
        typename Settings, 
        template <typename> class Customization>
    auto HalfMesh<Settings, Customization>::findFreeIncident(
        const Vertex_ConstIterator& vertex) const
        -> Half_ConstIterator
    {
        ASSERT(!vertex.empty());
        ASSERT(!vertex->isolated());

        Half_ConstIterator begin = vertex->half()->pair();
        Half_ConstIterator current = begin;
        do
        {
            if (current->left().empty())
            {
                return current;
            }
            current = current->next()->pair();
        }
        while (current != begin);

        return Half_ConstIterator();
    }

    template <
        typename Settings, 
        template <typename> class Customization>
    auto HalfMesh<Settings, Customization>::findFreeIncident(
        const Vertex_ConstIterator& vertex, 
        const Half_ConstIterator& startingFrom,
        const Half_ConstIterator& andBefore) const
        -> Half_ConstIterator
    {
        ASSERT(!vertex.empty());
        ASSERT(!vertex->isolated());
        ASSERT(!startingFrom.empty());
        ASSERT(startingFrom->destination() == vertex);
        ASSERT(!andBefore.empty());
        ASSERT(andBefore->destination() == vertex);

        if (andBefore == startingFrom)
        {
            return Half_ConstIterator();
        }

        Half_ConstIterator current = startingFrom;
        do
        {
            if (current->left().empty())
            {
                return current;
            }
            current = current->next()->pair();
        }
        while (current != andBefore);

        return Half_ConstIterator();
    }

}

#endif